reconnect moved files to git repo

venv/lib/python3.11/site-packages/scipy/integrate/_ivp/tests/test_rk.py

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+import pytest
+from numpy.testing import assert_allclose, assert_
+import numpy as np
+from scipy.integrate import RK23, RK45, DOP853
+from scipy.integrate._ivp import dop853_coefficients
+
+
+@pytest.mark.parametrize("solver", [RK23, RK45, DOP853])
+def test_coefficient_properties(solver):
+    assert_allclose(np.sum(solver.B), 1, rtol=1e-15)
+    assert_allclose(np.sum(solver.A, axis=1), solver.C, rtol=1e-14)
+
+
+def test_coefficient_properties_dop853():
+    assert_allclose(np.sum(dop853_coefficients.B), 1, rtol=1e-15)
+    assert_allclose(np.sum(dop853_coefficients.A, axis=1),
+                    dop853_coefficients.C,
+                    rtol=1e-14)
+
+
+@pytest.mark.parametrize("solver_class", [RK23, RK45, DOP853])
+def test_error_estimation(solver_class):
+    step = 0.2
+    solver = solver_class(lambda t, y: y, 0, [1], 1, first_step=step)
+    solver.step()
+    error_estimate = solver._estimate_error(solver.K, step)
+    error = solver.y - np.exp([step])
+    assert_(np.abs(error) < np.abs(error_estimate))
+
+
+@pytest.mark.parametrize("solver_class", [RK23, RK45, DOP853])
+def test_error_estimation_complex(solver_class):
+    h = 0.2
+    solver = solver_class(lambda t, y: 1j * y, 0, [1j], 1, first_step=h)
+    solver.step()
+    err_norm = solver._estimate_error_norm(solver.K, h, scale=[1])
+    assert np.isrealobj(err_norm)