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