asd

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_expm_multiply.py

@@ -0,0 +1,349 @@
+"""Test functions for the sparse.linalg._expm_multiply module."""
+from functools import partial
+from itertools import product
+
+import numpy as np
+import pytest
+from numpy.testing import (assert_allclose, assert_, assert_equal,
+                           suppress_warnings)
+from scipy.sparse import SparseEfficiencyWarning
+from scipy.sparse.linalg import aslinearoperator
+import scipy.linalg
+from scipy.sparse.linalg import expm as sp_expm
+from scipy.sparse.linalg._expm_multiply import (_theta, _compute_p_max,
+        _onenormest_matrix_power, expm_multiply, _expm_multiply_simple,
+        _expm_multiply_interval)
+from scipy._lib._util import np_long
+
+
+IMPRECISE = {np.single, np.csingle}
+REAL_DTYPES = {np.intc, np_long, np.longlong,
+               np.float32, np.float64, np.longdouble}
+COMPLEX_DTYPES = {np.complex64, np.complex128, np.clongdouble}
+# use sorted list to ensure fixed order of tests
+DTYPES = sorted(REAL_DTYPES ^ COMPLEX_DTYPES, key=str)
+
+
+def estimated(func):
+    """If trace is estimated, it should warn.
+
+    We warn that estimation of trace might impact performance.
+    All result have to be correct nevertheless!
+
+    """
+    def wrapped(*args, **kwds):
+        with pytest.warns(UserWarning,
+                          match="Trace of LinearOperator not available"):
+            return func(*args, **kwds)
+    return wrapped
+
+
+def less_than_or_close(a, b):
+    return np.allclose(a, b) or (a < b)
+
+
+class TestExpmActionSimple:
+    """
+    These tests do not consider the case of multiple time steps in one call.
+    """
+
+    def test_theta_monotonicity(self):
+        pairs = sorted(_theta.items())
+        for (m_a, theta_a), (m_b, theta_b) in zip(pairs[:-1], pairs[1:]):
+            assert_(theta_a < theta_b)
+
+    def test_p_max_default(self):
+        m_max = 55
+        expected_p_max = 8
+        observed_p_max = _compute_p_max(m_max)
+        assert_equal(observed_p_max, expected_p_max)
+
+    def test_p_max_range(self):
+        for m_max in range(1, 55+1):
+            p_max = _compute_p_max(m_max)
+            assert_(p_max*(p_max - 1) <= m_max + 1)
+            p_too_big = p_max + 1
+            assert_(p_too_big*(p_too_big - 1) > m_max + 1)
+
+    def test_onenormest_matrix_power(self):
+        np.random.seed(1234)
+        n = 40
+        nsamples = 10
+        for i in range(nsamples):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            for p in range(4):
+                if not p:
+                    M = np.identity(n)
+                else:
+                    M = np.dot(M, A)
+                estimated = _onenormest_matrix_power(A, p)
+                exact = np.linalg.norm(M, 1)
+                assert_(less_than_or_close(estimated, exact))
+                assert_(less_than_or_close(exact, 3*estimated))
+
+    def test_expm_multiply(self):
+        np.random.seed(1234)
+        n = 40
+        k = 3
+        nsamples = 10
+        for i in range(nsamples):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            B = np.random.randn(n, k)
+            observed = expm_multiply(A, B)
+            expected = np.dot(sp_expm(A), B)
+            assert_allclose(observed, expected)
+            observed = estimated(expm_multiply)(aslinearoperator(A), B)
+            assert_allclose(observed, expected)
+            traceA = np.trace(A)
+            observed = expm_multiply(aslinearoperator(A), B, traceA=traceA)
+            assert_allclose(observed, expected)
+
+    def test_matrix_vector_multiply(self):
+        np.random.seed(1234)
+        n = 40
+        nsamples = 10
+        for i in range(nsamples):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            v = np.random.randn(n)
+            observed = expm_multiply(A, v)
+            expected = np.dot(sp_expm(A), v)
+            assert_allclose(observed, expected)
+            observed = estimated(expm_multiply)(aslinearoperator(A), v)
+            assert_allclose(observed, expected)
+
+    def test_scaled_expm_multiply(self):
+        np.random.seed(1234)
+        n = 40
+        k = 3
+        nsamples = 10
+        for i, t in product(range(nsamples), [0.2, 1.0, 1.5]):
+            with np.errstate(invalid='ignore'):
+                A = scipy.linalg.inv(np.random.randn(n, n))
+                B = np.random.randn(n, k)
+                observed = _expm_multiply_simple(A, B, t=t)
+                expected = np.dot(sp_expm(t*A), B)
+                assert_allclose(observed, expected)
+                observed = estimated(_expm_multiply_simple)(
+                    aslinearoperator(A), B, t=t
+                )
+                assert_allclose(observed, expected)
+
+    def test_scaled_expm_multiply_single_timepoint(self):
+        np.random.seed(1234)
+        t = 0.1
+        n = 5
+        k = 2
+        A = np.random.randn(n, n)
+        B = np.random.randn(n, k)
+        observed = _expm_multiply_simple(A, B, t=t)
+        expected = sp_expm(t*A).dot(B)
+        assert_allclose(observed, expected)
+        observed = estimated(_expm_multiply_simple)(
+            aslinearoperator(A), B, t=t
+        )
+        assert_allclose(observed, expected)
+
+    def test_sparse_expm_multiply(self):
+        np.random.seed(1234)
+        n = 40
+        k = 3
+        nsamples = 10
+        for i in range(nsamples):
+            A = scipy.sparse.rand(n, n, density=0.05)
+            B = np.random.randn(n, k)
+            observed = expm_multiply(A, B)
+            with suppress_warnings() as sup:
+                sup.filter(SparseEfficiencyWarning,
+                           "splu converted its input to CSC format")
+                sup.filter(SparseEfficiencyWarning,
+                           "spsolve is more efficient when sparse b is in the"
+                           " CSC matrix format")
+                expected = sp_expm(A).dot(B)
+            assert_allclose(observed, expected)
+            observed = estimated(expm_multiply)(aslinearoperator(A), B)
+            assert_allclose(observed, expected)
+
+    def test_complex(self):
+        A = np.array([
+            [1j, 1j],
+            [0, 1j]], dtype=complex)
+        B = np.array([1j, 1j])
+        observed = expm_multiply(A, B)
+        expected = np.array([
+            1j * np.exp(1j) + 1j * (1j*np.cos(1) - np.sin(1)),
+            1j * np.exp(1j)], dtype=complex)
+        assert_allclose(observed, expected)
+        observed = estimated(expm_multiply)(aslinearoperator(A), B)
+        assert_allclose(observed, expected)
+
+
+class TestExpmActionInterval:
+
+    @pytest.mark.fail_slow(5)
+    def test_sparse_expm_multiply_interval(self):
+        np.random.seed(1234)
+        start = 0.1
+        stop = 3.2
+        n = 40
+        k = 3
+        endpoint = True
+        for num in (14, 13, 2):
+            A = scipy.sparse.rand(n, n, density=0.05)
+            B = np.random.randn(n, k)
+            v = np.random.randn(n)
+            for target in (B, v):
+                X = expm_multiply(A, target, start=start, stop=stop,
+                                  num=num, endpoint=endpoint)
+                samples = np.linspace(start=start, stop=stop,
+                                      num=num, endpoint=endpoint)
+                with suppress_warnings() as sup:
+                    sup.filter(SparseEfficiencyWarning,
+                               "splu converted its input to CSC format")
+                    sup.filter(SparseEfficiencyWarning,
+                               "spsolve is more efficient when sparse b is in"
+                               " the CSC matrix format")
+                    for solution, t in zip(X, samples):
+                        assert_allclose(solution, sp_expm(t*A).dot(target))
+
+    @pytest.mark.fail_slow(5)
+    def test_expm_multiply_interval_vector(self):
+        np.random.seed(1234)
+        interval = {'start': 0.1, 'stop': 3.2, 'endpoint': True}
+        for num, n in product([14, 13, 2], [1, 2, 5, 20, 40]):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            v = np.random.randn(n)
+            samples = np.linspace(num=num, **interval)
+            X = expm_multiply(A, v, num=num, **interval)
+            for solution, t in zip(X, samples):
+                assert_allclose(solution, sp_expm(t*A).dot(v))
+            # test for linear operator with unknown trace -> estimate trace
+            Xguess = estimated(expm_multiply)(aslinearoperator(A), v,
+                                              num=num, **interval)
+            # test for linear operator with given trace
+            Xgiven = expm_multiply(aslinearoperator(A), v, num=num, **interval,
+                                   traceA=np.trace(A))
+            # test robustness for linear operator with wrong trace
+            Xwrong = expm_multiply(aslinearoperator(A), v, num=num, **interval,
+                                   traceA=np.trace(A)*5)
+            for sol_guess, sol_given, sol_wrong, t in zip(Xguess, Xgiven,
+                                                          Xwrong, samples):
+                correct = sp_expm(t*A).dot(v)
+                assert_allclose(sol_guess, correct)
+                assert_allclose(sol_given, correct)
+                assert_allclose(sol_wrong, correct)
+
+    @pytest.mark.fail_slow(5)
+    def test_expm_multiply_interval_matrix(self):
+        np.random.seed(1234)
+        interval = {'start': 0.1, 'stop': 3.2, 'endpoint': True}
+        for num, n, k in product([14, 13, 2], [1, 2, 5, 20, 40], [1, 2]):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            B = np.random.randn(n, k)
+            samples = np.linspace(num=num, **interval)
+            X = expm_multiply(A, B, num=num, **interval)
+            for solution, t in zip(X, samples):
+                assert_allclose(solution, sp_expm(t*A).dot(B))
+            X = estimated(expm_multiply)(aslinearoperator(A), B, num=num,
+                                         **interval)
+            for solution, t in zip(X, samples):
+                assert_allclose(solution, sp_expm(t*A).dot(B))
+
+    def test_sparse_expm_multiply_interval_dtypes(self):
+        # Test A & B int
+        A = scipy.sparse.diags(np.arange(5),format='csr', dtype=int)
+        B = np.ones(5, dtype=int)
+        Aexpm = scipy.sparse.diags(np.exp(np.arange(5)),format='csr')
+        assert_allclose(expm_multiply(A,B,0,1)[-1], Aexpm.dot(B))
+
+        # Test A complex, B int
+        A = scipy.sparse.diags(-1j*np.arange(5),format='csr', dtype=complex)
+        B = np.ones(5, dtype=int)
+        Aexpm = scipy.sparse.diags(np.exp(-1j*np.arange(5)),format='csr')
+        assert_allclose(expm_multiply(A,B,0,1)[-1], Aexpm.dot(B))
+
+        # Test A int, B complex
+        A = scipy.sparse.diags(np.arange(5),format='csr', dtype=int)
+        B = np.full(5, 1j, dtype=complex)
+        Aexpm = scipy.sparse.diags(np.exp(np.arange(5)),format='csr')
+        assert_allclose(expm_multiply(A,B,0,1)[-1], Aexpm.dot(B))
+
+    def test_expm_multiply_interval_status_0(self):
+        self._help_test_specific_expm_interval_status(0)
+
+    def test_expm_multiply_interval_status_1(self):
+        self._help_test_specific_expm_interval_status(1)
+
+    def test_expm_multiply_interval_status_2(self):
+        self._help_test_specific_expm_interval_status(2)
+
+    def _help_test_specific_expm_interval_status(self, target_status):
+        np.random.seed(1234)
+        start = 0.1
+        stop = 3.2
+        num = 13
+        endpoint = True
+        n = 5
+        k = 2
+        nrepeats = 10
+        nsuccesses = 0
+        for num in [14, 13, 2] * nrepeats:
+            A = np.random.randn(n, n)
+            B = np.random.randn(n, k)
+            status = _expm_multiply_interval(A, B,
+                    start=start, stop=stop, num=num, endpoint=endpoint,
+                    status_only=True)
+            if status == target_status:
+                X, status = _expm_multiply_interval(A, B,
+                        start=start, stop=stop, num=num, endpoint=endpoint,
+                        status_only=False)
+                assert_equal(X.shape, (num, n, k))
+                samples = np.linspace(start=start, stop=stop,
+                        num=num, endpoint=endpoint)
+                for solution, t in zip(X, samples):
+                    assert_allclose(solution, sp_expm(t*A).dot(B))
+                nsuccesses += 1
+        if not nsuccesses:
+            msg = 'failed to find a status-' + str(target_status) + ' interval'
+            raise Exception(msg)
+
+
+@pytest.mark.parametrize("dtype_a", DTYPES)
+@pytest.mark.parametrize("dtype_b", DTYPES)
+@pytest.mark.parametrize("b_is_matrix", [False, True])
+def test_expm_multiply_dtype(dtype_a, dtype_b, b_is_matrix):
+    """Make sure `expm_multiply` handles all numerical dtypes correctly."""
+    assert_allclose_ = (partial(assert_allclose, rtol=1.2e-3, atol=1e-5)
+                        if {dtype_a, dtype_b} & IMPRECISE else assert_allclose)
+    rng = np.random.default_rng(1234)
+    # test data
+    n = 7
+    b_shape = (n, 3) if b_is_matrix else (n, )
+    if dtype_a in REAL_DTYPES:
+        A = scipy.linalg.inv(rng.random([n, n])).astype(dtype_a)
+    else:
+        A = scipy.linalg.inv(
+            rng.random([n, n]) + 1j*rng.random([n, n])
+        ).astype(dtype_a)
+    if dtype_b in REAL_DTYPES:
+        B = (2*rng.random(b_shape)).astype(dtype_b)
+    else:
+        B = (rng.random(b_shape) + 1j*rng.random(b_shape)).astype(dtype_b)
+
+    # single application
+    sol_mat = expm_multiply(A, B)
+    sol_op = estimated(expm_multiply)(aslinearoperator(A), B)
+    direct_sol = np.dot(sp_expm(A), B)
+    assert_allclose_(sol_mat, direct_sol)
+    assert_allclose_(sol_op, direct_sol)
+    sol_op = expm_multiply(aslinearoperator(A), B, traceA=np.trace(A))
+    assert_allclose_(sol_op, direct_sol)
+
+    # for time points
+    interval = {'start': 0.1, 'stop': 3.2, 'num': 13, 'endpoint': True}
+    samples = np.linspace(**interval)
+    X_mat = expm_multiply(A, B, **interval)
+    X_op = estimated(expm_multiply)(aslinearoperator(A), B, **interval)
+    for sol_mat, sol_op, t in zip(X_mat, X_op, samples):
+        direct_sol = sp_expm(t*A).dot(B)
+        assert_allclose_(sol_mat, direct_sol)
+        assert_allclose_(sol_op, direct_sol)

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_interface.py

@@ -0,0 +1,481 @@
+"""Test functions for the sparse.linalg._interface module
+"""
+
+from functools import partial
+from itertools import product
+import operator
+from pytest import raises as assert_raises, warns
+from numpy.testing import assert_, assert_equal
+
+import numpy as np
+import scipy.sparse as sparse
+
+import scipy.sparse.linalg._interface as interface
+from scipy.sparse._sputils import matrix
+
+
+class TestLinearOperator:
+    def setup_method(self):
+        self.A = np.array([[1,2,3],
+                           [4,5,6]])
+        self.B = np.array([[1,2],
+                           [3,4],
+                           [5,6]])
+        self.C = np.array([[1,2],
+                           [3,4]])
+
+    def test_matvec(self):
+        def get_matvecs(A):
+            return [{
+                        'shape': A.shape,
+                        'matvec': lambda x: np.dot(A, x).reshape(A.shape[0]),
+                        'rmatvec': lambda x: np.dot(A.T.conj(),
+                                                    x).reshape(A.shape[1])
+                    },
+                    {
+                        'shape': A.shape,
+                        'matvec': lambda x: np.dot(A, x),
+                        'rmatvec': lambda x: np.dot(A.T.conj(), x),
+                        'rmatmat': lambda x: np.dot(A.T.conj(), x),
+                        'matmat': lambda x: np.dot(A, x)
+                    }]
+
+        for matvecs in get_matvecs(self.A):
+            A = interface.LinearOperator(**matvecs)
+
+            assert_(A.args == ())
+
+            assert_equal(A.matvec(np.array([1,2,3])), [14,32])
+            assert_equal(A.matvec(np.array([[1],[2],[3]])), [[14],[32]])
+            assert_equal(A * np.array([1,2,3]), [14,32])
+            assert_equal(A * np.array([[1],[2],[3]]), [[14],[32]])
+            assert_equal(A.dot(np.array([1,2,3])), [14,32])
+            assert_equal(A.dot(np.array([[1],[2],[3]])), [[14],[32]])
+
+            assert_equal(A.matvec(matrix([[1],[2],[3]])), [[14],[32]])
+            assert_equal(A * matrix([[1],[2],[3]]), [[14],[32]])
+            assert_equal(A.dot(matrix([[1],[2],[3]])), [[14],[32]])
+
+            assert_equal((2*A)*[1,1,1], [12,30])
+            assert_equal((2 * A).rmatvec([1, 1]), [10, 14, 18])
+            assert_equal((2*A).H.matvec([1,1]), [10, 14, 18])
+            assert_equal((2*A)*[[1],[1],[1]], [[12],[30]])
+            assert_equal((2 * A).matmat([[1], [1], [1]]), [[12], [30]])
+            assert_equal((A*2)*[1,1,1], [12,30])
+            assert_equal((A*2)*[[1],[1],[1]], [[12],[30]])
+            assert_equal((2j*A)*[1,1,1], [12j,30j])
+            assert_equal((A+A)*[1,1,1], [12, 30])
+            assert_equal((A + A).rmatvec([1, 1]), [10, 14, 18])
+            assert_equal((A+A).H.matvec([1,1]), [10, 14, 18])
+            assert_equal((A+A)*[[1],[1],[1]], [[12], [30]])
+            assert_equal((A+A).matmat([[1],[1],[1]]), [[12], [30]])
+            assert_equal((-A)*[1,1,1], [-6,-15])
+            assert_equal((-A)*[[1],[1],[1]], [[-6],[-15]])
+            assert_equal((A-A)*[1,1,1], [0,0])
+            assert_equal((A - A) * [[1], [1], [1]], [[0], [0]])
+
+            X = np.array([[1, 2], [3, 4]])
+            # A_asarray = np.array([[1, 2, 3], [4, 5, 6]])
+            assert_equal((2 * A).rmatmat(X), np.dot((2 * self.A).T, X))
+            assert_equal((A * 2).rmatmat(X), np.dot((self.A * 2).T, X))
+            assert_equal((2j * A).rmatmat(X),
+                         np.dot((2j * self.A).T.conj(), X))
+            assert_equal((A * 2j).rmatmat(X),
+                         np.dot((self.A * 2j).T.conj(), X))
+            assert_equal((A + A).rmatmat(X),
+                         np.dot((self.A + self.A).T, X))
+            assert_equal((A + 2j * A).rmatmat(X),
+                         np.dot((self.A + 2j * self.A).T.conj(), X))
+            assert_equal((-A).rmatmat(X), np.dot((-self.A).T, X))
+            assert_equal((A - A).rmatmat(X),
+                         np.dot((self.A - self.A).T, X))
+            assert_equal((2j * A).rmatmat(2j * X),
+                         np.dot((2j * self.A).T.conj(), 2j * X))
+
+            z = A+A
+            assert_(len(z.args) == 2 and z.args[0] is A and z.args[1] is A)
+            z = 2*A
+            assert_(len(z.args) == 2 and z.args[0] is A and z.args[1] == 2)
+
+            assert_(isinstance(A.matvec([1, 2, 3]), np.ndarray))
+            assert_(isinstance(A.matvec(np.array([[1],[2],[3]])), np.ndarray))
+            assert_(isinstance(A * np.array([1,2,3]), np.ndarray))
+            assert_(isinstance(A * np.array([[1],[2],[3]]), np.ndarray))
+            assert_(isinstance(A.dot(np.array([1,2,3])), np.ndarray))
+            assert_(isinstance(A.dot(np.array([[1],[2],[3]])), np.ndarray))
+
+            assert_(isinstance(A.matvec(matrix([[1],[2],[3]])), np.ndarray))
+            assert_(isinstance(A * matrix([[1],[2],[3]]), np.ndarray))
+            assert_(isinstance(A.dot(matrix([[1],[2],[3]])), np.ndarray))
+
+            assert_(isinstance(2*A, interface._ScaledLinearOperator))
+            assert_(isinstance(2j*A, interface._ScaledLinearOperator))
+            assert_(isinstance(A+A, interface._SumLinearOperator))
+            assert_(isinstance(-A, interface._ScaledLinearOperator))
+            assert_(isinstance(A-A, interface._SumLinearOperator))
+            assert_(isinstance(A/2, interface._ScaledLinearOperator))
+            assert_(isinstance(A/2j, interface._ScaledLinearOperator))
+            assert_(((A * 3) / 3).args[0] is A)  # check for simplification
+
+            # Test that prefactor is of _ScaledLinearOperator is not mutated
+            # when the operator is multiplied by a number
+            result = A @ np.array([1, 2, 3])
+            B = A * 3
+            C = A / 5
+            assert_equal(A @ np.array([1, 2, 3]), result)
+
+            assert_((2j*A).dtype == np.complex128)
+
+            # Test division by non-scalar
+            msg = "Can only divide a linear operator by a scalar."
+            with assert_raises(ValueError, match=msg):
+                A / np.array([1, 2])
+
+            assert_raises(ValueError, A.matvec, np.array([1,2]))
+            assert_raises(ValueError, A.matvec, np.array([1,2,3,4]))
+            assert_raises(ValueError, A.matvec, np.array([[1],[2]]))
+            assert_raises(ValueError, A.matvec, np.array([[1],[2],[3],[4]]))
+
+            assert_raises(ValueError, lambda: A*A)
+            assert_raises(ValueError, lambda: A**2)
+
+        for matvecsA, matvecsB in product(get_matvecs(self.A),
+                                          get_matvecs(self.B)):
+            A = interface.LinearOperator(**matvecsA)
+            B = interface.LinearOperator(**matvecsB)
+            # AtimesB = np.array([[22, 28], [49, 64]])
+            AtimesB = self.A.dot(self.B)
+            X = np.array([[1, 2], [3, 4]])
+
+            assert_equal((A * B).rmatmat(X), np.dot((AtimesB).T, X))
+            assert_equal((2j * A * B).rmatmat(X),
+                         np.dot((2j * AtimesB).T.conj(), X))
+
+            assert_equal((A*B)*[1,1], [50,113])
+            assert_equal((A*B)*[[1],[1]], [[50],[113]])
+            assert_equal((A*B).matmat([[1],[1]]), [[50],[113]])
+
+            assert_equal((A * B).rmatvec([1, 1]), [71, 92])
+            assert_equal((A * B).H.matvec([1, 1]), [71, 92])
+
+            assert_(isinstance(A*B, interface._ProductLinearOperator))
+
+            assert_raises(ValueError, lambda: A+B)
+            assert_raises(ValueError, lambda: A**2)
+
+            z = A*B
+            assert_(len(z.args) == 2 and z.args[0] is A and z.args[1] is B)
+
+        for matvecsC in get_matvecs(self.C):
+            C = interface.LinearOperator(**matvecsC)
+            X = np.array([[1, 2], [3, 4]])
+
+            assert_equal(C.rmatmat(X), np.dot((self.C).T, X))
+            assert_equal((C**2).rmatmat(X),
+                         np.dot((np.dot(self.C, self.C)).T, X))
+
+            assert_equal((C**2)*[1,1], [17,37])
+            assert_equal((C**2).rmatvec([1, 1]), [22, 32])
+            assert_equal((C**2).H.matvec([1, 1]), [22, 32])
+            assert_equal((C**2).matmat([[1],[1]]), [[17],[37]])
+
+            assert_(isinstance(C**2, interface._PowerLinearOperator))
+
+    def test_matmul(self):
+        D = {'shape': self.A.shape,
+             'matvec': lambda x: np.dot(self.A, x).reshape(self.A.shape[0]),
+             'rmatvec': lambda x: np.dot(self.A.T.conj(),
+                                         x).reshape(self.A.shape[1]),
+             'rmatmat': lambda x: np.dot(self.A.T.conj(), x),
+             'matmat': lambda x: np.dot(self.A, x)}
+        A = interface.LinearOperator(**D)
+        B = np.array([[1 + 1j, 2, 3],
+                      [4, 5, 6],
+                      [7, 8, 9]])
+        b = B[0]
+
+        assert_equal(operator.matmul(A, b), A * b)
+        assert_equal(operator.matmul(A, b.reshape(-1, 1)), A * b.reshape(-1, 1))
+        assert_equal(operator.matmul(A, B), A * B)
+        assert_equal(operator.matmul(b, A.H), b * A.H)
+        assert_equal(operator.matmul(b.reshape(1, -1), A.H), b.reshape(1, -1) * A.H)
+        assert_equal(operator.matmul(B, A.H), B * A.H)
+        assert_raises(ValueError, operator.matmul, A, 2)
+        assert_raises(ValueError, operator.matmul, 2, A)
+
+
+class TestAsLinearOperator:
+    def setup_method(self):
+        self.cases = []
+
+        def make_cases(original, dtype):
+            cases = []
+
+            cases.append((matrix(original, dtype=dtype), original))
+            cases.append((np.array(original, dtype=dtype), original))
+            cases.append((sparse.csr_matrix(original, dtype=dtype), original))
+
+            # Test default implementations of _adjoint and _rmatvec, which
+            # refer to each other.
+            def mv(x, dtype):
+                y = original.dot(x)
+                if len(x.shape) == 2:
+                    y = y.reshape(-1, 1)
+                return y
+
+            def rmv(x, dtype):
+                return original.T.conj().dot(x)
+
+            class BaseMatlike(interface.LinearOperator):
+                args = ()
+
+                def __init__(self, dtype):
+                    self.dtype = np.dtype(dtype)
+                    self.shape = original.shape
+
+                def _matvec(self, x):
+                    return mv(x, self.dtype)
+
+            class HasRmatvec(BaseMatlike):
+                args = ()
+
+                def _rmatvec(self,x):
+                    return rmv(x, self.dtype)
+
+            class HasAdjoint(BaseMatlike):
+                args = ()
+
+                def _adjoint(self):
+                    shape = self.shape[1], self.shape[0]
+                    matvec = partial(rmv, dtype=self.dtype)
+                    rmatvec = partial(mv, dtype=self.dtype)
+                    return interface.LinearOperator(matvec=matvec,
+                                                    rmatvec=rmatvec,
+                                                    dtype=self.dtype,
+                                                    shape=shape)
+
+            class HasRmatmat(HasRmatvec):
+                def _matmat(self, x):
+                    return original.dot(x)
+
+                def _rmatmat(self, x):
+                    return original.T.conj().dot(x)
+
+            cases.append((HasRmatvec(dtype), original))
+            cases.append((HasAdjoint(dtype), original))
+            cases.append((HasRmatmat(dtype), original))
+            return cases
+
+        original = np.array([[1,2,3], [4,5,6]])
+        self.cases += make_cases(original, np.int32)
+        self.cases += make_cases(original, np.float32)
+        self.cases += make_cases(original, np.float64)
+        self.cases += [(interface.aslinearoperator(M).T, A.T)
+                       for M, A in make_cases(original.T, np.float64)]
+        self.cases += [(interface.aslinearoperator(M).H, A.T.conj())
+                       for M, A in make_cases(original.T, np.float64)]
+
+        original = np.array([[1, 2j, 3j], [4j, 5j, 6]])
+        self.cases += make_cases(original, np.complex128)
+        self.cases += [(interface.aslinearoperator(M).T, A.T)
+                       for M, A in make_cases(original.T, np.complex128)]
+        self.cases += [(interface.aslinearoperator(M).H, A.T.conj())
+                       for M, A in make_cases(original.T, np.complex128)]
+
+    def test_basic(self):
+
+        for M, A_array in self.cases:
+            A = interface.aslinearoperator(M)
+            M,N = A.shape
+
+            xs = [np.array([1, 2, 3]),
+                  np.array([[1], [2], [3]])]
+            ys = [np.array([1, 2]), np.array([[1], [2]])]
+
+            if A.dtype == np.complex128:
+                xs += [np.array([1, 2j, 3j]),
+                       np.array([[1], [2j], [3j]])]
+                ys += [np.array([1, 2j]), np.array([[1], [2j]])]
+
+            x2 = np.array([[1, 4], [2, 5], [3, 6]])
+
+            for x in xs:
+                assert_equal(A.matvec(x), A_array.dot(x))
+                assert_equal(A * x, A_array.dot(x))
+
+            assert_equal(A.matmat(x2), A_array.dot(x2))
+            assert_equal(A * x2, A_array.dot(x2))
+
+            for y in ys:
+                assert_equal(A.rmatvec(y), A_array.T.conj().dot(y))
+                assert_equal(A.T.matvec(y), A_array.T.dot(y))
+                assert_equal(A.H.matvec(y), A_array.T.conj().dot(y))
+
+            for y in ys:
+                if y.ndim < 2:
+                    continue
+                assert_equal(A.rmatmat(y), A_array.T.conj().dot(y))
+                assert_equal(A.T.matmat(y), A_array.T.dot(y))
+                assert_equal(A.H.matmat(y), A_array.T.conj().dot(y))
+
+            if hasattr(M,'dtype'):
+                assert_equal(A.dtype, M.dtype)
+
+            assert_(hasattr(A, 'args'))
+
+    def test_dot(self):
+
+        for M, A_array in self.cases:
+            A = interface.aslinearoperator(M)
+            M,N = A.shape
+
+            x0 = np.array([1, 2, 3])
+            x1 = np.array([[1], [2], [3]])
+            x2 = np.array([[1, 4], [2, 5], [3, 6]])
+
+            assert_equal(A.dot(x0), A_array.dot(x0))
+            assert_equal(A.dot(x1), A_array.dot(x1))
+            assert_equal(A.dot(x2), A_array.dot(x2))
+
+
+def test_repr():
+    A = interface.LinearOperator(shape=(1, 1), matvec=lambda x: 1)
+    repr_A = repr(A)
+    assert_('unspecified dtype' not in repr_A, repr_A)
+
+
+def test_identity():
+    ident = interface.IdentityOperator((3, 3))
+    assert_equal(ident * [1, 2, 3], [1, 2, 3])
+    assert_equal(ident.dot(np.arange(9).reshape(3, 3)).ravel(), np.arange(9))
+
+    assert_raises(ValueError, ident.matvec, [1, 2, 3, 4])
+
+
+def test_attributes():
+    A = interface.aslinearoperator(np.arange(16).reshape(4, 4))
+
+    def always_four_ones(x):
+        x = np.asarray(x)
+        assert_(x.shape == (3,) or x.shape == (3, 1))
+        return np.ones(4)
+
+    B = interface.LinearOperator(shape=(4, 3), matvec=always_four_ones)
+
+    for op in [A, B, A * B, A.H, A + A, B + B, A**4]:
+        assert_(hasattr(op, "dtype"))
+        assert_(hasattr(op, "shape"))
+        assert_(hasattr(op, "_matvec"))
+
+def matvec(x):
+    """ Needed for test_pickle as local functions are not pickleable """
+    return np.zeros(3)
+
+def test_pickle():
+    import pickle
+
+    for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+        A = interface.LinearOperator((3, 3), matvec)
+        s = pickle.dumps(A, protocol=protocol)
+        B = pickle.loads(s)
+
+        for k in A.__dict__:
+            assert_equal(getattr(A, k), getattr(B, k))
+
+def test_inheritance():
+    class Empty(interface.LinearOperator):
+        pass
+
+    with warns(RuntimeWarning, match="should implement at least"):
+        assert_raises(TypeError, Empty)
+
+    class Identity(interface.LinearOperator):
+        def __init__(self, n):
+            super().__init__(dtype=None, shape=(n, n))
+
+        def _matvec(self, x):
+            return x
+
+    id3 = Identity(3)
+    assert_equal(id3.matvec([1, 2, 3]), [1, 2, 3])
+    assert_raises(NotImplementedError, id3.rmatvec, [4, 5, 6])
+
+    class MatmatOnly(interface.LinearOperator):
+        def __init__(self, A):
+            super().__init__(A.dtype, A.shape)
+            self.A = A
+
+        def _matmat(self, x):
+            return self.A.dot(x)
+
+    mm = MatmatOnly(np.random.randn(5, 3))
+    assert_equal(mm.matvec(np.random.randn(3)).shape, (5,))
+
+def test_dtypes_of_operator_sum():
+    # gh-6078
+
+    mat_complex = np.random.rand(2,2) + 1j * np.random.rand(2,2)
+    mat_real = np.random.rand(2,2)
+
+    complex_operator = interface.aslinearoperator(mat_complex)
+    real_operator = interface.aslinearoperator(mat_real)
+
+    sum_complex = complex_operator + complex_operator
+    sum_real = real_operator + real_operator
+
+    assert_equal(sum_real.dtype, np.float64)
+    assert_equal(sum_complex.dtype, np.complex128)
+
+def test_no_double_init():
+    call_count = [0]
+
+    def matvec(v):
+        call_count[0] += 1
+        return v
+
+    # It should call matvec exactly once (in order to determine the
+    # operator dtype)
+    interface.LinearOperator((2, 2), matvec=matvec)
+    assert_equal(call_count[0], 1)
+
+def test_adjoint_conjugate():
+    X = np.array([[1j]])
+    A = interface.aslinearoperator(X)
+
+    B = 1j * A
+    Y = 1j * X
+
+    v = np.array([1])
+
+    assert_equal(B.dot(v), Y.dot(v))
+    assert_equal(B.H.dot(v), Y.T.conj().dot(v))
+
+def test_ndim():
+    X = np.array([[1]])
+    A = interface.aslinearoperator(X)
+    assert_equal(A.ndim, 2)
+
+def test_transpose_noconjugate():
+    X = np.array([[1j]])
+    A = interface.aslinearoperator(X)
+
+    B = 1j * A
+    Y = 1j * X
+
+    v = np.array([1])
+
+    assert_equal(B.dot(v), Y.dot(v))
+    assert_equal(B.T.dot(v), Y.T.dot(v))
+
+def test_sparse_matmat_exception():
+    A = interface.LinearOperator((2, 2), matvec=lambda x: x)
+    B = sparse.identity(2)
+    msg = "Unable to multiply a LinearOperator with a sparse matrix."
+    with assert_raises(TypeError, match=msg):
+        A @ B
+    with assert_raises(TypeError, match=msg):
+        B @ A
+    with assert_raises(ValueError):
+        A @ np.identity(4)
+    with assert_raises(ValueError):
+        np.identity(4) @ A

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_matfuncs.py

@@ -0,0 +1,592 @@
+#
+# Created by: Pearu Peterson, March 2002
+#
+""" Test functions for scipy.linalg._matfuncs module
+
+"""
+import math
+
+import numpy as np
+from numpy import array, eye, exp, random
+from numpy.testing import (
+        assert_allclose, assert_, assert_array_almost_equal, assert_equal,
+        assert_array_almost_equal_nulp, suppress_warnings)
+
+from scipy.sparse import csc_matrix, csc_array, SparseEfficiencyWarning
+from scipy.sparse._construct import eye as speye
+from scipy.sparse.linalg._matfuncs import (expm, _expm,
+        ProductOperator, MatrixPowerOperator,
+        _onenorm_matrix_power_nnm, matrix_power)
+from scipy.sparse._sputils import matrix
+from scipy.linalg import logm
+from scipy.special import factorial, binom
+import scipy.sparse
+import scipy.sparse.linalg
+
+
+def _burkardt_13_power(n, p):
+    """
+    A helper function for testing matrix functions.
+
+    Parameters
+    ----------
+    n : integer greater than 1
+        Order of the square matrix to be returned.
+    p : non-negative integer
+        Power of the matrix.
+
+    Returns
+    -------
+    out : ndarray representing a square matrix
+        A Forsythe matrix of order n, raised to the power p.
+
+    """
+    # Input validation.
+    if n != int(n) or n < 2:
+        raise ValueError('n must be an integer greater than 1')
+    n = int(n)
+    if p != int(p) or p < 0:
+        raise ValueError('p must be a non-negative integer')
+    p = int(p)
+
+    # Construct the matrix explicitly.
+    a, b = divmod(p, n)
+    large = np.power(10.0, -n*a)
+    small = large * np.power(10.0, -n)
+    return np.diag([large]*(n-b), b) + np.diag([small]*b, b-n)
+
+
+def test_onenorm_matrix_power_nnm():
+    np.random.seed(1234)
+    for n in range(1, 5):
+        for p in range(5):
+            M = np.random.random((n, n))
+            Mp = np.linalg.matrix_power(M, p)
+            observed = _onenorm_matrix_power_nnm(M, p)
+            expected = np.linalg.norm(Mp, 1)
+            assert_allclose(observed, expected)
+
+def test_matrix_power():
+    np.random.seed(1234)
+    row, col = np.random.randint(0, 4, size=(2, 6))
+    data = np.random.random(size=(6,))
+    Amat = csc_matrix((data, (row, col)), shape=(4, 4))
+    A = csc_array((data, (row, col)), shape=(4, 4))
+    Adense = A.toarray()
+    for power in (2, 5, 6):
+        Apow = matrix_power(A, power).toarray()
+        Amat_pow = (Amat**power).toarray()
+        Adense_pow = np.linalg.matrix_power(Adense, power)
+        assert_allclose(Apow, Adense_pow)
+        assert_allclose(Apow, Amat_pow)
+
+
+class TestExpM:
+    def test_zero_ndarray(self):
+        a = array([[0.,0],[0,0]])
+        assert_array_almost_equal(expm(a),[[1,0],[0,1]])
+
+    def test_zero_sparse(self):
+        a = csc_matrix([[0.,0],[0,0]])
+        assert_array_almost_equal(expm(a).toarray(),[[1,0],[0,1]])
+
+    def test_zero_matrix(self):
+        a = matrix([[0.,0],[0,0]])
+        assert_array_almost_equal(expm(a),[[1,0],[0,1]])
+
+    def test_misc_types(self):
+        A = expm(np.array([[1]]))
+        assert_allclose(expm(((1,),)), A)
+        assert_allclose(expm([[1]]), A)
+        assert_allclose(expm(matrix([[1]])), A)
+        assert_allclose(expm(np.array([[1]])), A)
+        assert_allclose(expm(csc_matrix([[1]])).toarray(), A)
+        B = expm(np.array([[1j]]))
+        assert_allclose(expm(((1j,),)), B)
+        assert_allclose(expm([[1j]]), B)
+        assert_allclose(expm(matrix([[1j]])), B)
+        assert_allclose(expm(csc_matrix([[1j]])).toarray(), B)
+
+    def test_bidiagonal_sparse(self):
+        A = csc_matrix([
+            [1, 3, 0],
+            [0, 1, 5],
+            [0, 0, 2]], dtype=float)
+        e1 = math.exp(1)
+        e2 = math.exp(2)
+        expected = np.array([
+            [e1, 3*e1, 15*(e2 - 2*e1)],
+            [0, e1, 5*(e2 - e1)],
+            [0, 0, e2]], dtype=float)
+        observed = expm(A).toarray()
+        assert_array_almost_equal(observed, expected)
+
+    def test_padecases_dtype_float(self):
+        for dtype in [np.float32, np.float64]:
+            for scale in [1e-2, 1e-1, 5e-1, 1, 10]:
+                A = scale * eye(3, dtype=dtype)
+                observed = expm(A)
+                expected = exp(scale, dtype=dtype) * eye(3, dtype=dtype)
+                assert_array_almost_equal_nulp(observed, expected, nulp=100)
+
+    def test_padecases_dtype_complex(self):
+        for dtype in [np.complex64, np.complex128]:
+            for scale in [1e-2, 1e-1, 5e-1, 1, 10]:
+                A = scale * eye(3, dtype=dtype)
+                observed = expm(A)
+                expected = exp(scale, dtype=dtype) * eye(3, dtype=dtype)
+                assert_array_almost_equal_nulp(observed, expected, nulp=100)
+
+    def test_padecases_dtype_sparse_float(self):
+        # float32 and complex64 lead to errors in spsolve/UMFpack
+        dtype = np.float64
+        for scale in [1e-2, 1e-1, 5e-1, 1, 10]:
+            a = scale * speye(3, 3, dtype=dtype, format='csc')
+            e = exp(scale, dtype=dtype) * eye(3, dtype=dtype)
+            with suppress_warnings() as sup:
+                sup.filter(SparseEfficiencyWarning, "Changing the sparsity structure")
+                exact_onenorm = _expm(a, use_exact_onenorm=True).toarray()
+                inexact_onenorm = _expm(a, use_exact_onenorm=False).toarray()
+            assert_array_almost_equal_nulp(exact_onenorm, e, nulp=100)
+            assert_array_almost_equal_nulp(inexact_onenorm, e, nulp=100)
+
+    def test_padecases_dtype_sparse_complex(self):
+        # float32 and complex64 lead to errors in spsolve/UMFpack
+        dtype = np.complex128
+        for scale in [1e-2, 1e-1, 5e-1, 1, 10]:
+            a = scale * speye(3, 3, dtype=dtype, format='csc')
+            e = exp(scale) * eye(3, dtype=dtype)
+            with suppress_warnings() as sup:
+                sup.filter(SparseEfficiencyWarning, "Changing the sparsity structure")
+                assert_array_almost_equal_nulp(expm(a).toarray(), e, nulp=100)
+
+    def test_logm_consistency(self):
+        random.seed(1234)
+        for dtype in [np.float64, np.complex128]:
+            for n in range(1, 10):
+                for scale in [1e-4, 1e-3, 1e-2, 1e-1, 1, 1e1, 1e2]:
+                    # make logm(A) be of a given scale
+                    A = (eye(n) + random.rand(n, n) * scale).astype(dtype)
+                    if np.iscomplexobj(A):
+                        A = A + 1j * random.rand(n, n) * scale
+                    assert_array_almost_equal(expm(logm(A)), A)
+
+    def test_integer_matrix(self):
+        Q = np.array([
+            [-3, 1, 1, 1],
+            [1, -3, 1, 1],
+            [1, 1, -3, 1],
+            [1, 1, 1, -3]])
+        assert_allclose(expm(Q), expm(1.0 * Q))
+
+    def test_integer_matrix_2(self):
+        # Check for integer overflows
+        Q = np.array([[-500, 500, 0, 0],
+                      [0, -550, 360, 190],
+                      [0, 630, -630, 0],
+                      [0, 0, 0, 0]], dtype=np.int16)
+        assert_allclose(expm(Q), expm(1.0 * Q))
+
+        Q = csc_matrix(Q)
+        assert_allclose(expm(Q).toarray(), expm(1.0 * Q).toarray())
+
+    def test_triangularity_perturbation(self):
+        # Experiment (1) of
+        # Awad H. Al-Mohy and Nicholas J. Higham (2012)
+        # Improved Inverse Scaling and Squaring Algorithms
+        # for the Matrix Logarithm.
+        A = np.array([
+            [3.2346e-1, 3e4, 3e4, 3e4],
+            [0, 3.0089e-1, 3e4, 3e4],
+            [0, 0, 3.221e-1, 3e4],
+            [0, 0, 0, 3.0744e-1]],
+            dtype=float)
+        A_logm = np.array([
+            [-1.12867982029050462e+00, 9.61418377142025565e+04,
+             -4.52485573953179264e+09, 2.92496941103871812e+14],
+            [0.00000000000000000e+00, -1.20101052953082288e+00,
+             9.63469687211303099e+04, -4.68104828911105442e+09],
+            [0.00000000000000000e+00, 0.00000000000000000e+00,
+             -1.13289322264498393e+00, 9.53249183094775653e+04],
+            [0.00000000000000000e+00, 0.00000000000000000e+00,
+             0.00000000000000000e+00, -1.17947533272554850e+00]],
+            dtype=float)
+        assert_allclose(expm(A_logm), A, rtol=1e-4)
+
+        # Perturb the upper triangular matrix by tiny amounts,
+        # so that it becomes technically not upper triangular.
+        random.seed(1234)
+        tiny = 1e-17
+        A_logm_perturbed = A_logm.copy()
+        A_logm_perturbed[1, 0] = tiny
+        with suppress_warnings() as sup:
+            sup.filter(RuntimeWarning, "Ill-conditioned.*")
+            A_expm_logm_perturbed = expm(A_logm_perturbed)
+        rtol = 1e-4
+        atol = 100 * tiny
+        assert_(not np.allclose(A_expm_logm_perturbed, A, rtol=rtol, atol=atol))
+
+    def test_burkardt_1(self):
+        # This matrix is diagonal.
+        # The calculation of the matrix exponential is simple.
+        #
+        # This is the first of a series of matrix exponential tests
+        # collected by John Burkardt from the following sources.
+        #
+        # Alan Laub,
+        # Review of "Linear System Theory" by Joao Hespanha,
+        # SIAM Review,
+        # Volume 52, Number 4, December 2010, pages 779--781.
+        #
+        # Cleve Moler and Charles Van Loan,
+        # Nineteen Dubious Ways to Compute the Exponential of a Matrix,
+        # Twenty-Five Years Later,
+        # SIAM Review,
+        # Volume 45, Number 1, March 2003, pages 3--49.
+        #
+        # Cleve Moler,
+        # Cleve's Corner: A Balancing Act for the Matrix Exponential,
+        # 23 July 2012.
+        #
+        # Robert Ward,
+        # Numerical computation of the matrix exponential
+        # with accuracy estimate,
+        # SIAM Journal on Numerical Analysis,
+        # Volume 14, Number 4, September 1977, pages 600--610.
+        exp1 = np.exp(1)
+        exp2 = np.exp(2)
+        A = np.array([
+            [1, 0],
+            [0, 2],
+            ], dtype=float)
+        desired = np.array([
+            [exp1, 0],
+            [0, exp2],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_2(self):
+        # This matrix is symmetric.
+        # The calculation of the matrix exponential is straightforward.
+        A = np.array([
+            [1, 3],
+            [3, 2],
+            ], dtype=float)
+        desired = np.array([
+            [39.322809708033859, 46.166301438885753],
+            [46.166301438885768, 54.711576854329110],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_3(self):
+        # This example is due to Laub.
+        # This matrix is ill-suited for the Taylor series approach.
+        # As powers of A are computed, the entries blow up too quickly.
+        exp1 = np.exp(1)
+        exp39 = np.exp(39)
+        A = np.array([
+            [0, 1],
+            [-39, -40],
+            ], dtype=float)
+        desired = np.array([
+            [
+                39/(38*exp1) - 1/(38*exp39),
+                -np.expm1(-38) / (38*exp1)],
+            [
+                39*np.expm1(-38) / (38*exp1),
+                -1/(38*exp1) + 39/(38*exp39)],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_4(self):
+        # This example is due to Moler and Van Loan.
+        # The example will cause problems for the series summation approach,
+        # as well as for diagonal Pade approximations.
+        A = np.array([
+            [-49, 24],
+            [-64, 31],
+            ], dtype=float)
+        U = np.array([[3, 1], [4, 2]], dtype=float)
+        V = np.array([[1, -1/2], [-2, 3/2]], dtype=float)
+        w = np.array([-17, -1], dtype=float)
+        desired = np.dot(U * np.exp(w), V)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_5(self):
+        # This example is due to Moler and Van Loan.
+        # This matrix is strictly upper triangular
+        # All powers of A are zero beyond some (low) limit.
+        # This example will cause problems for Pade approximations.
+        A = np.array([
+            [0, 6, 0, 0],
+            [0, 0, 6, 0],
+            [0, 0, 0, 6],
+            [0, 0, 0, 0],
+            ], dtype=float)
+        desired = np.array([
+            [1, 6, 18, 36],
+            [0, 1, 6, 18],
+            [0, 0, 1, 6],
+            [0, 0, 0, 1],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_6(self):
+        # This example is due to Moler and Van Loan.
+        # This matrix does not have a complete set of eigenvectors.
+        # That means the eigenvector approach will fail.
+        exp1 = np.exp(1)
+        A = np.array([
+            [1, 1],
+            [0, 1],
+            ], dtype=float)
+        desired = np.array([
+            [exp1, exp1],
+            [0, exp1],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_7(self):
+        # This example is due to Moler and Van Loan.
+        # This matrix is very close to example 5.
+        # Mathematically, it has a complete set of eigenvectors.
+        # Numerically, however, the calculation will be suspect.
+        exp1 = np.exp(1)
+        eps = np.spacing(1)
+        A = np.array([
+            [1 + eps, 1],
+            [0, 1 - eps],
+            ], dtype=float)
+        desired = np.array([
+            [exp1, exp1],
+            [0, exp1],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_8(self):
+        # This matrix was an example in Wikipedia.
+        exp4 = np.exp(4)
+        exp16 = np.exp(16)
+        A = np.array([
+            [21, 17, 6],
+            [-5, -1, -6],
+            [4, 4, 16],
+            ], dtype=float)
+        desired = np.array([
+            [13*exp16 - exp4, 13*exp16 - 5*exp4, 2*exp16 - 2*exp4],
+            [-9*exp16 + exp4, -9*exp16 + 5*exp4, -2*exp16 + 2*exp4],
+            [16*exp16, 16*exp16, 4*exp16],
+            ], dtype=float) * 0.25
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_9(self):
+        # This matrix is due to the NAG Library.
+        # It is an example for function F01ECF.
+        A = np.array([
+            [1, 2, 2, 2],
+            [3, 1, 1, 2],
+            [3, 2, 1, 2],
+            [3, 3, 3, 1],
+            ], dtype=float)
+        desired = np.array([
+            [740.7038, 610.8500, 542.2743, 549.1753],
+            [731.2510, 603.5524, 535.0884, 542.2743],
+            [823.7630, 679.4257, 603.5524, 610.8500],
+            [998.4355, 823.7630, 731.2510, 740.7038],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_10(self):
+        # This is Ward's example #1.
+        # It is defective and nonderogatory.
+        A = np.array([
+            [4, 2, 0],
+            [1, 4, 1],
+            [1, 1, 4],
+            ], dtype=float)
+        assert_allclose(sorted(scipy.linalg.eigvals(A)), (3, 3, 6))
+        desired = np.array([
+            [147.8666224463699, 183.7651386463682, 71.79703239999647],
+            [127.7810855231823, 183.7651386463682, 91.88256932318415],
+            [127.7810855231824, 163.6796017231806, 111.9681062463718],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_11(self):
+        # This is Ward's example #2.
+        # It is a symmetric matrix.
+        A = np.array([
+            [29.87942128909879, 0.7815750847907159, -2.289519314033932],
+            [0.7815750847907159, 25.72656945571064, 8.680737820540137],
+            [-2.289519314033932, 8.680737820540137, 34.39400925519054],
+            ], dtype=float)
+        assert_allclose(scipy.linalg.eigvalsh(A), (20, 30, 40))
+        desired = np.array([
+             [
+                 5.496313853692378E+15,
+                 -1.823188097200898E+16,
+                 -3.047577080858001E+16],
+             [
+                -1.823188097200899E+16,
+                6.060522870222108E+16,
+                1.012918429302482E+17],
+             [
+                -3.047577080858001E+16,
+                1.012918429302482E+17,
+                1.692944112408493E+17],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_12(self):
+        # This is Ward's example #3.
+        # Ward's algorithm has difficulty estimating the accuracy
+        # of its results.
+        A = np.array([
+            [-131, 19, 18],
+            [-390, 56, 54],
+            [-387, 57, 52],
+            ], dtype=float)
+        assert_allclose(sorted(scipy.linalg.eigvals(A)), (-20, -2, -1))
+        desired = np.array([
+            [-1.509644158793135, 0.3678794391096522, 0.1353352811751005],
+            [-5.632570799891469, 1.471517758499875, 0.4060058435250609],
+            [-4.934938326088363, 1.103638317328798, 0.5413411267617766],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_burkardt_13(self):
+        # This is Ward's example #4.
+        # This is a version of the Forsythe matrix.
+        # The eigenvector problem is badly conditioned.
+        # Ward's algorithm has difficulty estimating the accuracy
+        # of its results for this problem.
+        #
+        # Check the construction of one instance of this family of matrices.
+        A4_actual = _burkardt_13_power(4, 1)
+        A4_desired = [[0, 1, 0, 0],
+                      [0, 0, 1, 0],
+                      [0, 0, 0, 1],
+                      [1e-4, 0, 0, 0]]
+        assert_allclose(A4_actual, A4_desired)
+        # Check the expm for a few instances.
+        for n in (2, 3, 4, 10):
+            # Approximate expm using Taylor series.
+            # This works well for this matrix family
+            # because each matrix in the summation,
+            # even before dividing by the factorial,
+            # is entrywise positive with max entry 10**(-floor(p/n)*n).
+            k = max(1, int(np.ceil(16/n)))
+            desired = np.zeros((n, n), dtype=float)
+            for p in range(n*k):
+                Ap = _burkardt_13_power(n, p)
+                assert_equal(np.min(Ap), 0)
+                assert_allclose(np.max(Ap), np.power(10, -np.floor(p/n)*n))
+                desired += Ap / factorial(p)
+            actual = expm(_burkardt_13_power(n, 1))
+            assert_allclose(actual, desired)
+
+    def test_burkardt_14(self):
+        # This is Moler's example.
+        # This badly scaled matrix caused problems for MATLAB's expm().
+        A = np.array([
+            [0, 1e-8, 0],
+            [-(2e10 + 4e8/6.), -3, 2e10],
+            [200./3., 0, -200./3.],
+            ], dtype=float)
+        desired = np.array([
+            [0.446849468283175, 1.54044157383952e-09, 0.462811453558774],
+            [-5743067.77947947, -0.0152830038686819, -4526542.71278401],
+            [0.447722977849494, 1.54270484519591e-09, 0.463480648837651],
+            ], dtype=float)
+        actual = expm(A)
+        assert_allclose(actual, desired)
+
+    def test_pascal(self):
+        # Test pascal triangle.
+        # Nilpotent exponential, used to trigger a failure (gh-8029)
+
+        for scale in [1.0, 1e-3, 1e-6]:
+            for n in range(0, 80, 3):
+                sc = scale ** np.arange(n, -1, -1)
+                if np.any(sc < 1e-300):
+                    break
+
+                A = np.diag(np.arange(1, n + 1), -1) * scale
+                B = expm(A)
+
+                got = B
+                expected = binom(np.arange(n + 1)[:,None],
+                                 np.arange(n + 1)[None,:]) * sc[None,:] / sc[:,None]
+                atol = 1e-13 * abs(expected).max()
+                assert_allclose(got, expected, atol=atol)
+
+    def test_matrix_input(self):
+        # Large np.matrix inputs should work, gh-5546
+        A = np.zeros((200, 200))
+        A[-1,0] = 1
+        B0 = expm(A)
+        with suppress_warnings() as sup:
+            sup.filter(DeprecationWarning, "the matrix subclass.*")
+            sup.filter(PendingDeprecationWarning, "the matrix subclass.*")
+            B = expm(np.matrix(A))
+        assert_allclose(B, B0)
+
+    def test_exp_sinch_overflow(self):
+        # Check overflow in intermediate steps is fixed (gh-11839)
+        L = np.array([[1.0, -0.5, -0.5, 0.0, 0.0, 0.0, 0.0],
+                      [0.0, 1.0, 0.0, -0.5, -0.5, 0.0, 0.0],
+                      [0.0, 0.0, 1.0, 0.0, 0.0, -0.5, -0.5],
+                      [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+                      [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+                      [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
+                      [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]])
+
+        E0 = expm(-L)
+        E1 = expm(-2**11 * L)
+        E2 = E0
+        for j in range(11):
+            E2 = E2 @ E2
+
+        assert_allclose(E1, E2)
+
+
+class TestOperators:
+
+    def test_product_operator(self):
+        random.seed(1234)
+        n = 5
+        k = 2
+        nsamples = 10
+        for i in range(nsamples):
+            A = np.random.randn(n, n)
+            B = np.random.randn(n, n)
+            C = np.random.randn(n, n)
+            D = np.random.randn(n, k)
+            op = ProductOperator(A, B, C)
+            assert_allclose(op.matmat(D), A.dot(B).dot(C).dot(D))
+            assert_allclose(op.T.matmat(D), (A.dot(B).dot(C)).T.dot(D))
+
+    def test_matrix_power_operator(self):
+        random.seed(1234)
+        n = 5
+        k = 2
+        p = 3
+        nsamples = 10
+        for i in range(nsamples):
+            A = np.random.randn(n, n)
+            B = np.random.randn(n, k)
+            op = MatrixPowerOperator(A, p)
+            assert_allclose(op.matmat(B), np.linalg.matrix_power(A, p).dot(B))
+            assert_allclose(op.T.matmat(B), np.linalg.matrix_power(A, p).T.dot(B))

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_norm.py

@@ -0,0 +1,141 @@
+"""Test functions for the sparse.linalg.norm module
+"""
+
+import pytest
+import numpy as np
+from numpy.linalg import norm as npnorm
+from numpy.testing import assert_allclose, assert_equal
+from pytest import raises as assert_raises
+
+import scipy.sparse
+from scipy.sparse.linalg import norm as spnorm
+
+
+# https://github.com/scipy/scipy/issues/16031
+def test_sparray_norm():
+    row = np.array([0, 0, 1, 1])
+    col = np.array([0, 1, 2, 3])
+    data = np.array([4, 5, 7, 9])
+    test_arr = scipy.sparse.coo_array((data, (row, col)), shape=(2, 4))
+    test_mat = scipy.sparse.coo_matrix((data, (row, col)), shape=(2, 4))
+    assert_equal(spnorm(test_arr, ord=1, axis=0), np.array([4, 5, 7, 9]))
+    assert_equal(spnorm(test_mat, ord=1, axis=0), np.array([4, 5, 7, 9]))
+    assert_equal(spnorm(test_arr, ord=1, axis=1), np.array([9, 16]))
+    assert_equal(spnorm(test_mat, ord=1, axis=1), np.array([9, 16]))
+
+
+class TestNorm:
+    def setup_method(self):
+        a = np.arange(9) - 4
+        b = a.reshape((3, 3))
+        self.b = scipy.sparse.csr_matrix(b)
+
+    def test_matrix_norm(self):
+
+        # Frobenius norm is the default
+        assert_allclose(spnorm(self.b), 7.745966692414834)        
+        assert_allclose(spnorm(self.b, 'fro'), 7.745966692414834)
+
+        assert_allclose(spnorm(self.b, np.inf), 9)
+        assert_allclose(spnorm(self.b, -np.inf), 2)
+        assert_allclose(spnorm(self.b, 1), 7)
+        assert_allclose(spnorm(self.b, -1), 6)
+        # Only floating or complex floating dtype supported by svds.
+        with pytest.warns(UserWarning, match="The problem size"):
+            assert_allclose(spnorm(self.b.astype(np.float64), 2),
+                            7.348469228349534)
+
+        # _multi_svd_norm is not implemented for sparse matrix
+        assert_raises(NotImplementedError, spnorm, self.b, -2)
+
+    def test_matrix_norm_axis(self):
+        for m, axis in ((self.b, None), (self.b, (0, 1)), (self.b.T, (1, 0))):
+            assert_allclose(spnorm(m, axis=axis), 7.745966692414834)        
+            assert_allclose(spnorm(m, 'fro', axis=axis), 7.745966692414834)
+            assert_allclose(spnorm(m, np.inf, axis=axis), 9)
+            assert_allclose(spnorm(m, -np.inf, axis=axis), 2)
+            assert_allclose(spnorm(m, 1, axis=axis), 7)
+            assert_allclose(spnorm(m, -1, axis=axis), 6)
+
+    def test_vector_norm(self):
+        v = [4.5825756949558398, 4.2426406871192848, 4.5825756949558398]
+        for m, a in (self.b, 0), (self.b.T, 1):
+            for axis in a, (a, ), a-2, (a-2, ):
+                assert_allclose(spnorm(m, 1, axis=axis), [7, 6, 7])
+                assert_allclose(spnorm(m, np.inf, axis=axis), [4, 3, 4])
+                assert_allclose(spnorm(m, axis=axis), v)
+                assert_allclose(spnorm(m, ord=2, axis=axis), v)
+                assert_allclose(spnorm(m, ord=None, axis=axis), v)
+
+    def test_norm_exceptions(self):
+        m = self.b
+        assert_raises(TypeError, spnorm, m, None, 1.5)
+        assert_raises(TypeError, spnorm, m, None, [2])
+        assert_raises(ValueError, spnorm, m, None, ())
+        assert_raises(ValueError, spnorm, m, None, (0, 1, 2))
+        assert_raises(ValueError, spnorm, m, None, (0, 0))
+        assert_raises(ValueError, spnorm, m, None, (0, 2))
+        assert_raises(ValueError, spnorm, m, None, (-3, 0))
+        assert_raises(ValueError, spnorm, m, None, 2)
+        assert_raises(ValueError, spnorm, m, None, -3)
+        assert_raises(ValueError, spnorm, m, 'plate_of_shrimp', 0)
+        assert_raises(ValueError, spnorm, m, 'plate_of_shrimp', (0, 1))
+
+
+class TestVsNumpyNorm:
+    _sparse_types = (
+            scipy.sparse.bsr_matrix,
+            scipy.sparse.coo_matrix,
+            scipy.sparse.csc_matrix,
+            scipy.sparse.csr_matrix,
+            scipy.sparse.dia_matrix,
+            scipy.sparse.dok_matrix,
+            scipy.sparse.lil_matrix,
+            )
+    _test_matrices = (
+            (np.arange(9) - 4).reshape((3, 3)),
+            [
+                [1, 2, 3],
+                [-1, 1, 4]],
+            [
+                [1, 0, 3],
+                [-1, 1, 4j]],
+            )
+
+    def test_sparse_matrix_norms(self):
+        for sparse_type in self._sparse_types:
+            for M in self._test_matrices:
+                S = sparse_type(M)
+                assert_allclose(spnorm(S), npnorm(M))
+                assert_allclose(spnorm(S, 'fro'), npnorm(M, 'fro'))
+                assert_allclose(spnorm(S, np.inf), npnorm(M, np.inf))
+                assert_allclose(spnorm(S, -np.inf), npnorm(M, -np.inf))
+                assert_allclose(spnorm(S, 1), npnorm(M, 1))
+                assert_allclose(spnorm(S, -1), npnorm(M, -1))
+
+    def test_sparse_matrix_norms_with_axis(self):
+        for sparse_type in self._sparse_types:
+            for M in self._test_matrices:
+                S = sparse_type(M)
+                for axis in None, (0, 1), (1, 0):
+                    assert_allclose(spnorm(S, axis=axis), npnorm(M, axis=axis))
+                    for ord in 'fro', np.inf, -np.inf, 1, -1:
+                        assert_allclose(spnorm(S, ord, axis=axis),
+                                        npnorm(M, ord, axis=axis))
+                # Some numpy matrix norms are allergic to negative axes.
+                for axis in (-2, -1), (-1, -2), (1, -2):
+                    assert_allclose(spnorm(S, axis=axis), npnorm(M, axis=axis))
+                    assert_allclose(spnorm(S, 'f', axis=axis),
+                                    npnorm(M, 'f', axis=axis))
+                    assert_allclose(spnorm(S, 'fro', axis=axis),
+                                    npnorm(M, 'fro', axis=axis))
+
+    def test_sparse_vector_norms(self):
+        for sparse_type in self._sparse_types:
+            for M in self._test_matrices:
+                S = sparse_type(M)
+                for axis in (0, 1, -1, -2, (0, ), (1, ), (-1, ), (-2, )):
+                    assert_allclose(spnorm(S, axis=axis), npnorm(M, axis=axis))
+                    for ord in None, 2, np.inf, -np.inf, 1, 0.5, 0.42:
+                        assert_allclose(spnorm(S, ord, axis=axis),
+                                        npnorm(M, ord, axis=axis))

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_onenormest.py

@@ -0,0 +1,252 @@
+"""Test functions for the sparse.linalg._onenormest module
+"""
+
+import numpy as np
+from numpy.testing import assert_allclose, assert_equal, assert_
+import pytest
+import scipy.linalg
+import scipy.sparse.linalg
+from scipy.sparse.linalg._onenormest import _onenormest_core, _algorithm_2_2
+
+
+class MatrixProductOperator(scipy.sparse.linalg.LinearOperator):
+    """
+    This is purely for onenormest testing.
+    """
+
+    def __init__(self, A, B):
+        if A.ndim != 2 or B.ndim != 2:
+            raise ValueError('expected ndarrays representing matrices')
+        if A.shape[1] != B.shape[0]:
+            raise ValueError('incompatible shapes')
+        self.A = A
+        self.B = B
+        self.ndim = 2
+        self.shape = (A.shape[0], B.shape[1])
+
+    def _matvec(self, x):
+        return np.dot(self.A, np.dot(self.B, x))
+
+    def _rmatvec(self, x):
+        return np.dot(np.dot(x, self.A), self.B)
+
+    def _matmat(self, X):
+        return np.dot(self.A, np.dot(self.B, X))
+
+    @property
+    def T(self):
+        return MatrixProductOperator(self.B.T, self.A.T)
+
+
+class TestOnenormest:
+
+    @pytest.mark.xslow
+    def test_onenormest_table_3_t_2(self):
+        # This will take multiple seconds if your computer is slow like mine.
+        # It is stochastic, so the tolerance could be too strict.
+        np.random.seed(1234)
+        t = 2
+        n = 100
+        itmax = 5
+        nsamples = 5000
+        observed = []
+        expected = []
+        nmult_list = []
+        nresample_list = []
+        for i in range(nsamples):
+            A = scipy.linalg.inv(np.random.randn(n, n))
+            est, v, w, nmults, nresamples = _onenormest_core(A, A.T, t, itmax)
+            observed.append(est)
+            expected.append(scipy.linalg.norm(A, 1))
+            nmult_list.append(nmults)
+            nresample_list.append(nresamples)
+        observed = np.array(observed, dtype=float)
+        expected = np.array(expected, dtype=float)
+        relative_errors = np.abs(observed - expected) / expected
+
+        # check the mean underestimation ratio
+        underestimation_ratio = observed / expected
+        assert_(0.99 < np.mean(underestimation_ratio) < 1.0)
+
+        # check the max and mean required column resamples
+        assert_equal(np.max(nresample_list), 2)
+        assert_(0.05 < np.mean(nresample_list) < 0.2)
+
+        # check the proportion of norms computed exactly correctly
+        nexact = np.count_nonzero(relative_errors < 1e-14)
+        proportion_exact = nexact / float(nsamples)
+        assert_(0.9 < proportion_exact < 0.95)
+
+        # check the average number of matrix*vector multiplications
+        assert_(3.5 < np.mean(nmult_list) < 4.5)
+
+    @pytest.mark.xslow
+    def test_onenormest_table_4_t_7(self):
+        # This will take multiple seconds if your computer is slow like mine.
+        # It is stochastic, so the tolerance could be too strict.
+        np.random.seed(1234)
+        t = 7
+        n = 100
+        itmax = 5
+        nsamples = 5000
+        observed = []
+        expected = []
+        nmult_list = []
+        nresample_list = []
+        for i in range(nsamples):
+            A = np.random.randint(-1, 2, size=(n, n))
+            est, v, w, nmults, nresamples = _onenormest_core(A, A.T, t, itmax)
+            observed.append(est)
+            expected.append(scipy.linalg.norm(A, 1))
+            nmult_list.append(nmults)
+            nresample_list.append(nresamples)
+        observed = np.array(observed, dtype=float)
+        expected = np.array(expected, dtype=float)
+        relative_errors = np.abs(observed - expected) / expected
+
+        # check the mean underestimation ratio
+        underestimation_ratio = observed / expected
+        assert_(0.90 < np.mean(underestimation_ratio) < 0.99)
+
+        # check the required column resamples
+        assert_equal(np.max(nresample_list), 0)
+
+        # check the proportion of norms computed exactly correctly
+        nexact = np.count_nonzero(relative_errors < 1e-14)
+        proportion_exact = nexact / float(nsamples)
+        assert_(0.15 < proportion_exact < 0.25)
+
+        # check the average number of matrix*vector multiplications
+        assert_(3.5 < np.mean(nmult_list) < 4.5)
+
+    def test_onenormest_table_5_t_1(self):
+        # "note that there is no randomness and hence only one estimate for t=1"
+        t = 1
+        n = 100
+        itmax = 5
+        alpha = 1 - 1e-6
+        A = -scipy.linalg.inv(np.identity(n) + alpha*np.eye(n, k=1))
+        first_col = np.array([1] + [0]*(n-1))
+        first_row = np.array([(-alpha)**i for i in range(n)])
+        B = -scipy.linalg.toeplitz(first_col, first_row)
+        assert_allclose(A, B)
+        est, v, w, nmults, nresamples = _onenormest_core(B, B.T, t, itmax)
+        exact_value = scipy.linalg.norm(B, 1)
+        underest_ratio = est / exact_value
+        assert_allclose(underest_ratio, 0.05, rtol=1e-4)
+        assert_equal(nmults, 11)
+        assert_equal(nresamples, 0)
+        # check the non-underscored version of onenormest
+        est_plain = scipy.sparse.linalg.onenormest(B, t=t, itmax=itmax)
+        assert_allclose(est, est_plain)
+
+    @pytest.mark.xslow
+    def test_onenormest_table_6_t_1(self):
+        #TODO this test seems to give estimates that match the table,
+        #TODO even though no attempt has been made to deal with
+        #TODO complex numbers in the one-norm estimation.
+        # This will take multiple seconds if your computer is slow like mine.
+        # It is stochastic, so the tolerance could be too strict.
+        np.random.seed(1234)
+        t = 1
+        n = 100
+        itmax = 5
+        nsamples = 5000
+        observed = []
+        expected = []
+        nmult_list = []
+        nresample_list = []
+        for i in range(nsamples):
+            A_inv = np.random.rand(n, n) + 1j * np.random.rand(n, n)
+            A = scipy.linalg.inv(A_inv)
+            est, v, w, nmults, nresamples = _onenormest_core(A, A.T, t, itmax)
+            observed.append(est)
+            expected.append(scipy.linalg.norm(A, 1))
+            nmult_list.append(nmults)
+            nresample_list.append(nresamples)
+        observed = np.array(observed, dtype=float)
+        expected = np.array(expected, dtype=float)
+        relative_errors = np.abs(observed - expected) / expected
+
+        # check the mean underestimation ratio
+        underestimation_ratio = observed / expected
+        underestimation_ratio_mean = np.mean(underestimation_ratio)
+        assert_(0.90 < underestimation_ratio_mean < 0.99)
+
+        # check the required column resamples
+        max_nresamples = np.max(nresample_list)
+        assert_equal(max_nresamples, 0)
+
+        # check the proportion of norms computed exactly correctly
+        nexact = np.count_nonzero(relative_errors < 1e-14)
+        proportion_exact = nexact / float(nsamples)
+        assert_(0.7 < proportion_exact < 0.8)
+
+        # check the average number of matrix*vector multiplications
+        mean_nmult = np.mean(nmult_list)
+        assert_(4 < mean_nmult < 5)
+
+    def _help_product_norm_slow(self, A, B):
+        # for profiling
+        C = np.dot(A, B)
+        return scipy.linalg.norm(C, 1)
+
+    def _help_product_norm_fast(self, A, B):
+        # for profiling
+        t = 2
+        itmax = 5
+        D = MatrixProductOperator(A, B)
+        est, v, w, nmults, nresamples = _onenormest_core(D, D.T, t, itmax)
+        return est
+
+    @pytest.mark.slow
+    def test_onenormest_linear_operator(self):
+        # Define a matrix through its product A B.
+        # Depending on the shapes of A and B,
+        # it could be easy to multiply this product by a small matrix,
+        # but it could be annoying to look at all of
+        # the entries of the product explicitly.
+        np.random.seed(1234)
+        n = 6000
+        k = 3
+        A = np.random.randn(n, k)
+        B = np.random.randn(k, n)
+        fast_estimate = self._help_product_norm_fast(A, B)
+        exact_value = self._help_product_norm_slow(A, B)
+        assert_(fast_estimate <= exact_value <= 3*fast_estimate,
+                f'fast: {fast_estimate:g}\nexact:{exact_value:g}')
+
+    def test_returns(self):
+        np.random.seed(1234)
+        A = scipy.sparse.rand(50, 50, 0.1)
+
+        s0 = scipy.linalg.norm(A.toarray(), 1)
+        s1, v = scipy.sparse.linalg.onenormest(A, compute_v=True)
+        s2, w = scipy.sparse.linalg.onenormest(A, compute_w=True)
+        s3, v2, w2 = scipy.sparse.linalg.onenormest(A, compute_w=True, compute_v=True)
+
+        assert_allclose(s1, s0, rtol=1e-9)
+        assert_allclose(np.linalg.norm(A.dot(v), 1), s0*np.linalg.norm(v, 1), rtol=1e-9)
+        assert_allclose(A.dot(v), w, rtol=1e-9)
+
+
+class TestAlgorithm_2_2:
+
+    def test_randn_inv(self):
+        np.random.seed(1234)
+        n = 20
+        nsamples = 100
+        for i in range(nsamples):
+
+            # Choose integer t uniformly between 1 and 3 inclusive.
+            t = np.random.randint(1, 4)
+
+            # Choose n uniformly between 10 and 40 inclusive.
+            n = np.random.randint(10, 41)
+
+            # Sample the inverse of a matrix with random normal entries.
+            A = scipy.linalg.inv(np.random.randn(n, n))
+
+            # Compute the 1-norm bounds.
+            g, ind = _algorithm_2_2(A, A.T, t)
+

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_propack.py

@@ -0,0 +1,166 @@
+import os
+import pytest
+
+import numpy as np
+from numpy.testing import assert_allclose
+from pytest import raises as assert_raises
+from scipy.sparse.linalg._svdp import _svdp
+from scipy.sparse import csr_matrix, csc_matrix
+
+
+# dtype_flavour to tolerance
+TOLS = {
+    np.float32: 1e-4,
+    np.float64: 1e-8,
+    np.complex64: 1e-4,
+    np.complex128: 1e-8,
+}
+
+
+def is_complex_type(dtype):
+    return np.dtype(dtype).kind == "c"
+
+
+_dtypes = []
+for dtype_flavour in TOLS.keys():
+    marks = []
+    if is_complex_type(dtype_flavour):
+        marks = [pytest.mark.slow]
+    _dtypes.append(pytest.param(dtype_flavour, marks=marks,
+                                id=dtype_flavour.__name__))
+_dtypes = tuple(_dtypes)  # type: ignore[assignment]
+
+
+def generate_matrix(constructor, n, m, f,
+                    dtype=float, rseed=0, **kwargs):
+    """Generate a random sparse matrix"""
+    rng = np.random.RandomState(rseed)
+    if is_complex_type(dtype):
+        M = (- 5 + 10 * rng.rand(n, m)
+             - 5j + 10j * rng.rand(n, m)).astype(dtype)
+    else:
+        M = (-5 + 10 * rng.rand(n, m)).astype(dtype)
+    M[M.real > 10 * f - 5] = 0
+    return constructor(M, **kwargs)
+
+
+def assert_orthogonal(u1, u2, rtol, atol):
+    """Check that the first k rows of u1 and u2 are orthogonal"""
+    A = abs(np.dot(u1.conj().T, u2))
+    assert_allclose(A, np.eye(u1.shape[1], u2.shape[1]), rtol=rtol, atol=atol)
+
+
+def check_svdp(n, m, constructor, dtype, k, irl_mode, which, f=0.8):
+    tol = TOLS[dtype]
+
+    M = generate_matrix(np.asarray, n, m, f, dtype)
+    Msp = constructor(M)
+
+    u1, sigma1, vt1 = np.linalg.svd(M, full_matrices=False)
+    u2, sigma2, vt2, _ = _svdp(Msp, k=k, which=which, irl_mode=irl_mode,
+                               tol=tol)
+
+    # check the which
+    if which.upper() == 'SM':
+        u1 = np.roll(u1, k, 1)
+        vt1 = np.roll(vt1, k, 0)
+        sigma1 = np.roll(sigma1, k)
+
+    # check that singular values agree
+    assert_allclose(sigma1[:k], sigma2, rtol=tol, atol=tol)
+
+    # check that singular vectors are orthogonal
+    assert_orthogonal(u1, u2, rtol=tol, atol=tol)
+    assert_orthogonal(vt1.T, vt2.T, rtol=tol, atol=tol)
+
+
+@pytest.mark.parametrize('ctor', (np.array, csr_matrix, csc_matrix))
+@pytest.mark.parametrize('dtype', _dtypes)
+@pytest.mark.parametrize('irl', (True, False))
+@pytest.mark.parametrize('which', ('LM', 'SM'))
+def test_svdp(ctor, dtype, irl, which):
+    np.random.seed(0)
+    n, m, k = 10, 20, 3
+    if which == 'SM' and not irl:
+        message = "`which`='SM' requires irl_mode=True"
+        with assert_raises(ValueError, match=message):
+            check_svdp(n, m, ctor, dtype, k, irl, which)
+    else:
+        check_svdp(n, m, ctor, dtype, k, irl, which)
+
+
+@pytest.mark.xslow
+@pytest.mark.parametrize('dtype', _dtypes)
+@pytest.mark.parametrize('irl', (False, True))
+@pytest.mark.timeout(120)  # True, complex64 > 60 s: prerel deps cov 64bit blas
+def test_examples(dtype, irl):
+    # Note: atol for complex64 bumped from 1e-4 to 1e-3 due to test failures
+    # with BLIS, Netlib, and MKL+AVX512 - see
+    # https://github.com/conda-forge/scipy-feedstock/pull/198#issuecomment-999180432
+    atol = {
+        np.float32: 1.3e-4,
+        np.float64: 1e-9,
+        np.complex64: 1e-3,
+        np.complex128: 1e-9,
+    }[dtype]
+
+    path_prefix = os.path.dirname(__file__)
+    # Test matrices from `illc1850.coord` and `mhd1280b.cua` distributed with
+    # PROPACK 2.1: http://sun.stanford.edu/~rmunk/PROPACK/
+    relative_path = "propack_test_data.npz"
+    filename = os.path.join(path_prefix, relative_path)
+    with np.load(filename, allow_pickle=True) as data:
+        if is_complex_type(dtype):
+            A = data['A_complex'].item().astype(dtype)
+        else:
+            A = data['A_real'].item().astype(dtype)
+
+    k = 200
+    u, s, vh, _ = _svdp(A, k, irl_mode=irl, random_state=0)
+
+    # complex example matrix has many repeated singular values, so check only
+    # beginning non-repeated singular vectors to avoid permutations
+    sv_check = 27 if is_complex_type(dtype) else k
+    u = u[:, :sv_check]
+    vh = vh[:sv_check, :]
+    s = s[:sv_check]
+
+    # Check orthogonality of singular vectors
+    assert_allclose(np.eye(u.shape[1]), u.conj().T @ u, atol=atol)
+    assert_allclose(np.eye(vh.shape[0]), vh @ vh.conj().T, atol=atol)
+
+    # Ensure the norm of the difference between the np.linalg.svd and
+    # PROPACK reconstructed matrices is small
+    u3, s3, vh3 = np.linalg.svd(A.todense())
+    u3 = u3[:, :sv_check]
+    s3 = s3[:sv_check]
+    vh3 = vh3[:sv_check, :]
+    A3 = u3 @ np.diag(s3) @ vh3
+    recon = u @ np.diag(s) @ vh
+    assert_allclose(np.linalg.norm(A3 - recon), 0, atol=atol)
+
+
+@pytest.mark.parametrize('shifts', (None, -10, 0, 1, 10, 70))
+@pytest.mark.parametrize('dtype', _dtypes[:2])
+def test_shifts(shifts, dtype):
+    np.random.seed(0)
+    n, k = 70, 10
+    A = np.random.random((n, n))
+    if shifts is not None and ((shifts < 0) or (k > min(n-1-shifts, n))):
+        with pytest.raises(ValueError):
+            _svdp(A, k, shifts=shifts, kmax=5*k, irl_mode=True)
+    else:
+        _svdp(A, k, shifts=shifts, kmax=5*k, irl_mode=True)
+
+
+@pytest.mark.slow
+@pytest.mark.xfail()
+def test_shifts_accuracy():
+    np.random.seed(0)
+    n, k = 70, 10
+    A = np.random.random((n, n)).astype(np.float64)
+    u1, s1, vt1, _ = _svdp(A, k, shifts=None, which='SM', irl_mode=True)
+    u2, s2, vt2, _ = _svdp(A, k, shifts=32, which='SM', irl_mode=True)
+    # shifts <= 32 doesn't agree with shifts > 32
+    # Does agree when which='LM' instead of 'SM'
+    assert_allclose(s1, s2)

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_pydata_sparse.py

@@ -0,0 +1,243 @@
+import pytest
+
+import numpy as np
+import scipy.sparse as sp
+import scipy.sparse.linalg as splin
+
+from numpy.testing import assert_allclose, assert_equal
+
+try:
+    import sparse
+except Exception:
+    sparse = None
+
+pytestmark = pytest.mark.skipif(sparse is None,
+                                reason="pydata/sparse not installed")
+
+
+msg = "pydata/sparse (0.15.1) does not implement necessary operations"
+
+
+sparse_params = (pytest.param("COO"),
+                 pytest.param("DOK", marks=[pytest.mark.xfail(reason=msg)]))
+
+scipy_sparse_classes = [
+    sp.bsr_matrix,
+    sp.csr_matrix,
+    sp.coo_matrix,
+    sp.csc_matrix,
+    sp.dia_matrix,
+    sp.dok_matrix
+]
+
+
+@pytest.fixture(params=sparse_params)
+def sparse_cls(request):
+    return getattr(sparse, request.param)
+
+
+@pytest.fixture(params=scipy_sparse_classes)
+def sp_sparse_cls(request):
+    return request.param
+
+
+@pytest.fixture
+def same_matrix(sparse_cls, sp_sparse_cls):
+    np.random.seed(1234)
+    A_dense = np.random.rand(9, 9)
+    return sp_sparse_cls(A_dense), sparse_cls(A_dense)
+
+
+@pytest.fixture
+def matrices(sparse_cls):
+    np.random.seed(1234)
+    A_dense = np.random.rand(9, 9)
+    A_dense = A_dense @ A_dense.T
+    A_sparse = sparse_cls(A_dense)
+    b = np.random.rand(9)
+    return A_dense, A_sparse, b
+
+
+def test_isolve_gmres(matrices):
+    # Several of the iterative solvers use the same
+    # isolve.utils.make_system wrapper code, so test just one of them.
+    A_dense, A_sparse, b = matrices
+    x, info = splin.gmres(A_sparse, b, atol=1e-15)
+    assert info == 0
+    assert isinstance(x, np.ndarray)
+    assert_allclose(A_sparse @ x, b)
+
+
+def test_lsmr(matrices):
+    A_dense, A_sparse, b = matrices
+    res0 = splin.lsmr(A_dense, b)
+    res = splin.lsmr(A_sparse, b)
+    assert_allclose(res[0], res0[0], atol=1e-3)
+
+
+# test issue 17012
+def test_lsmr_output_shape():
+    x = splin.lsmr(A=np.ones((10, 1)), b=np.zeros(10), x0=np.ones(1))[0]
+    assert_equal(x.shape, (1,))
+
+
+def test_lsqr(matrices):
+    A_dense, A_sparse, b = matrices
+    res0 = splin.lsqr(A_dense, b)
+    res = splin.lsqr(A_sparse, b)
+    assert_allclose(res[0], res0[0], atol=1e-5)
+
+
+def test_eigs(matrices):
+    A_dense, A_sparse, v0 = matrices
+
+    M_dense = np.diag(v0**2)
+    M_sparse = A_sparse.__class__(M_dense)
+
+    w_dense, v_dense = splin.eigs(A_dense, k=3, v0=v0)
+    w, v = splin.eigs(A_sparse, k=3, v0=v0)
+
+    assert_allclose(w, w_dense)
+    assert_allclose(v, v_dense)
+
+    for M in [M_sparse, M_dense]:
+        w_dense, v_dense = splin.eigs(A_dense, M=M_dense, k=3, v0=v0)
+        w, v = splin.eigs(A_sparse, M=M, k=3, v0=v0)
+
+        assert_allclose(w, w_dense)
+        assert_allclose(v, v_dense)
+
+        w_dense, v_dense = splin.eigsh(A_dense, M=M_dense, k=3, v0=v0)
+        w, v = splin.eigsh(A_sparse, M=M, k=3, v0=v0)
+
+        assert_allclose(w, w_dense)
+        assert_allclose(v, v_dense)
+
+
+def test_svds(matrices):
+    A_dense, A_sparse, v0 = matrices
+
+    u0, s0, vt0 = splin.svds(A_dense, k=2, v0=v0)
+    u, s, vt = splin.svds(A_sparse, k=2, v0=v0)
+
+    assert_allclose(s, s0)
+    assert_allclose(np.abs(u), np.abs(u0))
+    assert_allclose(np.abs(vt), np.abs(vt0))
+
+
+def test_lobpcg(matrices):
+    A_dense, A_sparse, x = matrices
+    X = x[:,None]
+
+    w_dense, v_dense = splin.lobpcg(A_dense, X)
+    w, v = splin.lobpcg(A_sparse, X)
+
+    assert_allclose(w, w_dense)
+    assert_allclose(v, v_dense)
+
+
+def test_spsolve(matrices):
+    A_dense, A_sparse, b = matrices
+    b2 = np.random.rand(len(b), 3)
+
+    x0 = splin.spsolve(sp.csc_matrix(A_dense), b)
+    x = splin.spsolve(A_sparse, b)
+    assert isinstance(x, np.ndarray)
+    assert_allclose(x, x0)
+
+    x0 = splin.spsolve(sp.csc_matrix(A_dense), b)
+    x = splin.spsolve(A_sparse, b, use_umfpack=True)
+    assert isinstance(x, np.ndarray)
+    assert_allclose(x, x0)
+
+    x0 = splin.spsolve(sp.csc_matrix(A_dense), b2)
+    x = splin.spsolve(A_sparse, b2)
+    assert isinstance(x, np.ndarray)
+    assert_allclose(x, x0)
+
+    x0 = splin.spsolve(sp.csc_matrix(A_dense),
+                       sp.csc_matrix(A_dense))
+    x = splin.spsolve(A_sparse, A_sparse)
+    assert isinstance(x, type(A_sparse))
+    assert_allclose(x.todense(), x0.todense())
+
+
+def test_splu(matrices):
+    A_dense, A_sparse, b = matrices
+    n = len(b)
+    sparse_cls = type(A_sparse)
+
+    lu = splin.splu(A_sparse)
+
+    assert isinstance(lu.L, sparse_cls)
+    assert isinstance(lu.U, sparse_cls)
+
+    _Pr_scipy = sp.csc_matrix((np.ones(n), (lu.perm_r, np.arange(n))))
+    _Pc_scipy = sp.csc_matrix((np.ones(n), (np.arange(n), lu.perm_c)))
+    Pr = sparse_cls.from_scipy_sparse(_Pr_scipy)
+    Pc = sparse_cls.from_scipy_sparse(_Pc_scipy)
+    A2 = Pr.T @ lu.L @ lu.U @ Pc.T
+
+    assert_allclose(A2.todense(), A_sparse.todense())
+
+    z = lu.solve(A_sparse.todense())
+    assert_allclose(z, np.eye(n), atol=1e-10)
+
+
+def test_spilu(matrices):
+    A_dense, A_sparse, b = matrices
+    sparse_cls = type(A_sparse)
+
+    lu = splin.spilu(A_sparse)
+
+    assert isinstance(lu.L, sparse_cls)
+    assert isinstance(lu.U, sparse_cls)
+
+    z = lu.solve(A_sparse.todense())
+    assert_allclose(z, np.eye(len(b)), atol=1e-3)
+
+
+def test_spsolve_triangular(matrices):
+    A_dense, A_sparse, b = matrices
+    A_sparse = sparse.tril(A_sparse)
+
+    x = splin.spsolve_triangular(A_sparse, b)
+    assert_allclose(A_sparse @ x, b)
+
+
+def test_onenormest(matrices):
+    A_dense, A_sparse, b = matrices
+    est0 = splin.onenormest(A_dense)
+    est = splin.onenormest(A_sparse)
+    assert_allclose(est, est0)
+
+
+def test_inv(matrices):
+    A_dense, A_sparse, b = matrices
+    x0 = splin.inv(sp.csc_matrix(A_dense))
+    x = splin.inv(A_sparse)
+    assert_allclose(x.todense(), x0.todense())
+
+
+def test_expm(matrices):
+    A_dense, A_sparse, b = matrices
+    x0 = splin.expm(sp.csc_matrix(A_dense))
+    x = splin.expm(A_sparse)
+    assert_allclose(x.todense(), x0.todense())
+
+
+def test_expm_multiply(matrices):
+    A_dense, A_sparse, b = matrices
+    x0 = splin.expm_multiply(A_dense, b)
+    x = splin.expm_multiply(A_sparse, b)
+    assert_allclose(x, x0)
+
+
+def test_eq(same_matrix):
+    sp_sparse, pd_sparse = same_matrix
+    assert (sp_sparse == pd_sparse).all()
+
+
+def test_ne(same_matrix):
+    sp_sparse, pd_sparse = same_matrix
+    assert not (sp_sparse != pd_sparse).any()

venv/lib/python3.12/site-packages/scipy/sparse/linalg/tests/test_special_sparse_arrays.py

@@ -0,0 +1,337 @@
+import pytest
+import numpy as np
+from numpy.testing import assert_array_equal, assert_allclose
+
+from scipy.sparse import diags, csgraph
+from scipy.linalg import eigh
+
+from scipy.sparse.linalg import LaplacianNd
+from scipy.sparse.linalg._special_sparse_arrays import Sakurai
+from scipy.sparse.linalg._special_sparse_arrays import MikotaPair
+
+INT_DTYPES = [np.int8, np.int16, np.int32, np.int64]
+REAL_DTYPES = [np.float32, np.float64]
+COMPLEX_DTYPES = [np.complex64, np.complex128]
+ALLDTYPES = INT_DTYPES + REAL_DTYPES + COMPLEX_DTYPES
+
+
+class TestLaplacianNd:
+    """
+    LaplacianNd tests
+    """
+
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_1d_specific_shape(self, bc):
+        lap = LaplacianNd(grid_shape=(6, ), boundary_conditions=bc)
+        lapa = lap.toarray()
+        if bc == 'neumann':
+            a = np.array(
+                [
+                    [-1, 1, 0, 0, 0, 0],
+                    [1, -2, 1, 0, 0, 0],
+                    [0, 1, -2, 1, 0, 0],
+                    [0, 0, 1, -2, 1, 0],
+                    [0, 0, 0, 1, -2, 1],
+                    [0, 0, 0, 0, 1, -1],
+                ]
+            )
+        elif bc == 'dirichlet':
+            a = np.array(
+                [
+                    [-2, 1, 0, 0, 0, 0],
+                    [1, -2, 1, 0, 0, 0],
+                    [0, 1, -2, 1, 0, 0],
+                    [0, 0, 1, -2, 1, 0],
+                    [0, 0, 0, 1, -2, 1],
+                    [0, 0, 0, 0, 1, -2],
+                ]
+            )
+        else:
+            a = np.array(
+                [
+                    [-2, 1, 0, 0, 0, 1],
+                    [1, -2, 1, 0, 0, 0],
+                    [0, 1, -2, 1, 0, 0],
+                    [0, 0, 1, -2, 1, 0],
+                    [0, 0, 0, 1, -2, 1],
+                    [1, 0, 0, 0, 1, -2],
+                ]
+            )
+        assert_array_equal(a, lapa)
+
+    def test_1d_with_graph_laplacian(self):
+        n = 6
+        G = diags(np.ones(n - 1), 1, format='dia')
+        Lf = csgraph.laplacian(G, symmetrized=True, form='function')
+        La = csgraph.laplacian(G, symmetrized=True, form='array')
+        grid_shape = (n,)
+        bc = 'neumann'
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc)
+        assert_array_equal(lap(np.eye(n)), -Lf(np.eye(n)))
+        assert_array_equal(lap.toarray(), -La.toarray())
+        # https://github.com/numpy/numpy/issues/24351
+        assert_array_equal(lap.tosparse().toarray(), -La.toarray())
+
+    @pytest.mark.parametrize('grid_shape', [(6, ), (2, 3), (2, 3, 4)])
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_eigenvalues(self, grid_shape, bc):
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc, dtype=np.float64)
+        L = lap.toarray()
+        eigvals = eigh(L, eigvals_only=True)
+        n = np.prod(grid_shape)
+        eigenvalues = lap.eigenvalues()
+        dtype = eigenvalues.dtype
+        atol = n * n * np.finfo(dtype).eps
+        # test the default ``m = None``
+        assert_allclose(eigenvalues, eigvals, atol=atol)
+        # test every ``m > 0``
+        for m in np.arange(1, n + 1):
+            assert_array_equal(lap.eigenvalues(m), eigenvalues[-m:])
+
+    @pytest.mark.parametrize('grid_shape', [(6, ), (2, 3), (2, 3, 4)])
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_eigenvectors(self, grid_shape, bc):
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc, dtype=np.float64)
+        n = np.prod(grid_shape)
+        eigenvalues = lap.eigenvalues()
+        eigenvectors = lap.eigenvectors()
+        dtype = eigenvectors.dtype
+        atol = n * n * max(np.finfo(dtype).eps, np.finfo(np.double).eps)
+        # test the default ``m = None`` every individual eigenvector
+        for i in np.arange(n):
+            r = lap.toarray() @ eigenvectors[:, i] - eigenvectors[:, i] * eigenvalues[i]
+            assert_allclose(r, np.zeros_like(r), atol=atol)
+        # test every ``m > 0``
+        for m in np.arange(1, n + 1):
+            e = lap.eigenvalues(m)
+            ev = lap.eigenvectors(m)
+            r = lap.toarray() @ ev - ev @ np.diag(e)
+            assert_allclose(r, np.zeros_like(r), atol=atol)
+
+    @pytest.mark.parametrize('grid_shape', [(6, ), (2, 3), (2, 3, 4)])
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_toarray_tosparse_consistency(self, grid_shape, bc):
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc)
+        n = np.prod(grid_shape)
+        assert_array_equal(lap.toarray(), lap(np.eye(n)))
+        assert_array_equal(lap.tosparse().toarray(), lap.toarray())
+
+    @pytest.mark.parametrize('dtype', ALLDTYPES)
+    @pytest.mark.parametrize('grid_shape', [(6, ), (2, 3), (2, 3, 4)])
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_linearoperator_shape_dtype(self, grid_shape, bc, dtype):
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc, dtype=dtype)
+        n = np.prod(grid_shape)
+        assert lap.shape == (n, n)
+        assert lap.dtype == dtype
+        assert_array_equal(
+            LaplacianNd(
+                grid_shape, boundary_conditions=bc, dtype=dtype
+            ).toarray(),
+            LaplacianNd(grid_shape, boundary_conditions=bc)
+            .toarray()
+            .astype(dtype),
+        )
+        assert_array_equal(
+            LaplacianNd(grid_shape, boundary_conditions=bc, dtype=dtype)
+            .tosparse()
+            .toarray(),
+            LaplacianNd(grid_shape, boundary_conditions=bc)
+            .tosparse()
+            .toarray()
+            .astype(dtype),
+        )
+
+    @pytest.mark.parametrize('dtype', ALLDTYPES)
+    @pytest.mark.parametrize('grid_shape', [(6, ), (2, 3), (2, 3, 4)])
+    @pytest.mark.parametrize('bc', ['neumann', 'dirichlet', 'periodic'])
+    def test_dot(self, grid_shape, bc, dtype):
+        """ Test the dot-product for type preservation and consistency.
+        """
+        lap = LaplacianNd(grid_shape, boundary_conditions=bc)
+        n = np.prod(grid_shape)
+        x0 = np.arange(n)
+        x1 = x0.reshape((-1, 1))
+        x2 = np.arange(2 * n).reshape((n, 2))
+        input_set = [x0, x1, x2]
+        for x in input_set:
+            y = lap.dot(x.astype(dtype))
+            assert x.shape == y.shape
+            assert y.dtype == dtype
+            if x.ndim == 2:
+                yy = lap.toarray() @ x.astype(dtype)
+                assert yy.dtype == dtype
+                np.array_equal(y, yy)
+
+    def test_boundary_conditions_value_error(self):
+        with pytest.raises(ValueError, match="Unknown value 'robin'"):
+            LaplacianNd(grid_shape=(6, ), boundary_conditions='robin')
+
+            
+class TestSakurai:
+    """
+    Sakurai tests
+    """
+
+    def test_specific_shape(self):
+        sak = Sakurai(6)
+        assert_array_equal(sak.toarray(), sak(np.eye(6)))
+        a = np.array(
+            [
+                [ 5, -4,  1,  0,  0,  0],
+                [-4,  6, -4,  1,  0,  0],
+                [ 1, -4,  6, -4,  1,  0],
+                [ 0,  1, -4,  6, -4,  1],
+                [ 0,  0,  1, -4,  6, -4],
+                [ 0,  0,  0,  1, -4,  5]
+            ]
+        )
+
+        np.array_equal(a, sak.toarray())
+        np.array_equal(sak.tosparse().toarray(), sak.toarray())
+        ab = np.array(
+            [
+                [ 1,  1,  1,  1,  1,  1],
+                [-4, -4, -4, -4, -4, -4],
+                [ 5,  6,  6,  6,  6,  5]
+            ]
+        )
+        np.array_equal(ab, sak.tobanded())
+        e = np.array(
+                [0.03922866, 0.56703972, 2.41789479, 5.97822974,
+                 10.54287655, 14.45473055]
+            )
+        np.array_equal(e, sak.eigenvalues())
+        np.array_equal(e[:2], sak.eigenvalues(2))
+
+    # `Sakurai` default `dtype` is `np.int8` as its entries are small integers
+    @pytest.mark.parametrize('dtype', ALLDTYPES)
+    def test_linearoperator_shape_dtype(self, dtype):
+        n = 7
+        sak = Sakurai(n, dtype=dtype)
+        assert sak.shape == (n, n)
+        assert sak.dtype == dtype
+        assert_array_equal(sak.toarray(), Sakurai(n).toarray().astype(dtype))
+        assert_array_equal(sak.tosparse().toarray(),
+                           Sakurai(n).tosparse().toarray().astype(dtype))
+
+    @pytest.mark.parametrize('dtype', ALLDTYPES)
+    @pytest.mark.parametrize('argument_dtype', ALLDTYPES)
+    def test_dot(self, dtype, argument_dtype):
+        """ Test the dot-product for type preservation and consistency.
+        """
+        result_dtype = np.promote_types(argument_dtype, dtype)
+        n = 5
+        sak = Sakurai(n)
+        x0 = np.arange(n)
+        x1 = x0.reshape((-1, 1))
+        x2 = np.arange(2 * n).reshape((n, 2))
+        input_set = [x0, x1, x2]
+        for x in input_set:
+            y = sak.dot(x.astype(argument_dtype))
+            assert x.shape == y.shape
+            assert np.can_cast(y.dtype, result_dtype)
+            if x.ndim == 2:
+                ya = sak.toarray() @ x.astype(argument_dtype)
+                np.array_equal(y, ya)
+                assert np.can_cast(ya.dtype, result_dtype)
+                ys = sak.tosparse() @ x.astype(argument_dtype)
+                np.array_equal(y, ys)
+                assert np.can_cast(ys.dtype, result_dtype)
+
+class TestMikotaPair:
+    """
+    MikotaPair tests
+    """
+    # both MikotaPair `LinearOperator`s share the same dtype
+    # while `MikotaK` `dtype` can be as small as its default `np.int32`
+    # since its entries are integers, the `MikotaM` involves inverses
+    # so its smallest still accurate `dtype` is `np.float32`
+    tested_types = REAL_DTYPES + COMPLEX_DTYPES
+
+    def test_specific_shape(self):
+        n = 6
+        mik = MikotaPair(n)
+        mik_k = mik.k
+        mik_m = mik.m
+        assert_array_equal(mik_k.toarray(), mik_k(np.eye(n)))
+        assert_array_equal(mik_m.toarray(), mik_m(np.eye(n)))
+
+        k = np.array(
+            [
+                [11, -5,  0,  0,  0,  0],
+                [-5,  9, -4,  0,  0,  0],
+                [ 0, -4,  7, -3,  0,  0],
+                [ 0,  0, -3,  5, -2,  0],
+                [ 0,  0,  0, -2,  3, -1],
+                [ 0,  0,  0,  0, -1,  1]
+            ]
+        )
+        np.array_equal(k, mik_k.toarray())
+        np.array_equal(mik_k.tosparse().toarray(), k)
+        kb = np.array(
+            [
+                [ 0, -5, -4, -3, -2, -1],
+                [11,  9,  7,  5,  3,  1]
+            ]
+        )
+        np.array_equal(kb, mik_k.tobanded())
+
+        minv = np.arange(1, n + 1)
+        np.array_equal(np.diag(1. / minv), mik_m.toarray())
+        np.array_equal(mik_m.tosparse().toarray(), mik_m.toarray())
+        np.array_equal(1. / minv, mik_m.tobanded())
+
+        e = np.array([ 1,  4,  9, 16, 25, 36])
+        np.array_equal(e, mik.eigenvalues())
+        np.array_equal(e[:2], mik.eigenvalues(2))
+
+    @pytest.mark.parametrize('dtype', tested_types)
+    def test_linearoperator_shape_dtype(self, dtype):
+        n = 7
+        mik = MikotaPair(n, dtype=dtype)
+        mik_k = mik.k
+        mik_m = mik.m
+        assert mik_k.shape == (n, n)
+        assert mik_k.dtype == dtype
+        assert mik_m.shape == (n, n)
+        assert mik_m.dtype == dtype
+        mik_default_dtype = MikotaPair(n)
+        mikd_k = mik_default_dtype.k
+        mikd_m = mik_default_dtype.m
+        assert mikd_k.shape == (n, n)
+        assert mikd_k.dtype == np.float64
+        assert mikd_m.shape == (n, n)
+        assert mikd_m.dtype == np.float64
+        assert_array_equal(mik_k.toarray(),
+                           mikd_k.toarray().astype(dtype))
+        assert_array_equal(mik_k.tosparse().toarray(),
+                           mikd_k.tosparse().toarray().astype(dtype))
+
+    @pytest.mark.parametrize('dtype', tested_types)
+    @pytest.mark.parametrize('argument_dtype', ALLDTYPES)
+    def test_dot(self, dtype, argument_dtype):
+        """ Test the dot-product for type preservation and consistency.
+        """
+        result_dtype = np.promote_types(argument_dtype, dtype)
+        n = 5
+        mik = MikotaPair(n, dtype=dtype)
+        mik_k = mik.k
+        mik_m = mik.m
+        x0 = np.arange(n)
+        x1 = x0.reshape((-1, 1))
+        x2 = np.arange(2 * n).reshape((n, 2))
+        lo_set = [mik_k, mik_m]
+        input_set = [x0, x1, x2]
+        for lo in lo_set:
+            for x in input_set:
+                y = lo.dot(x.astype(argument_dtype))
+                assert x.shape == y.shape
+                assert np.can_cast(y.dtype, result_dtype)
+                if x.ndim == 2:
+                    ya = lo.toarray() @ x.astype(argument_dtype)
+                    np.array_equal(y, ya)
+                    assert np.can_cast(ya.dtype, result_dtype)
+                    ys = lo.tosparse() @ x.astype(argument_dtype)
+                    np.array_equal(y, ys)
+                    assert np.can_cast(ys.dtype, result_dtype)