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67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
6 years ago
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from __future__ import division, print_function, absolute_import
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from numpy.testing import (assert_array_equal, assert_array_almost_equal)
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from scipy.interpolate import pade
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def test_pade_trivial():
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nump, denomp = pade([1.0], 0)
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assert_array_equal(nump.c, [1.0])
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assert_array_equal(denomp.c, [1.0])
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nump, denomp = pade([1.0], 0, 0)
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assert_array_equal(nump.c, [1.0])
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assert_array_equal(denomp.c, [1.0])
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def test_pade_4term_exp():
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# First four Taylor coefficients of exp(x).
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# Unlike poly1d, the first array element is the zero-order term.
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an = [1.0, 1.0, 0.5, 1.0/6]
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nump, denomp = pade(an, 0)
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assert_array_almost_equal(nump.c, [1.0/6, 0.5, 1.0, 1.0])
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assert_array_almost_equal(denomp.c, [1.0])
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nump, denomp = pade(an, 1)
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assert_array_almost_equal(nump.c, [1.0/6, 2.0/3, 1.0])
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assert_array_almost_equal(denomp.c, [-1.0/3, 1.0])
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nump, denomp = pade(an, 2)
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assert_array_almost_equal(nump.c, [1.0/3, 1.0])
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assert_array_almost_equal(denomp.c, [1.0/6, -2.0/3, 1.0])
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nump, denomp = pade(an, 3)
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assert_array_almost_equal(nump.c, [1.0])
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assert_array_almost_equal(denomp.c, [-1.0/6, 0.5, -1.0, 1.0])
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# Testing inclusion of optional parameter
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nump, denomp = pade(an, 0, 3)
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assert_array_almost_equal(nump.c, [1.0/6, 0.5, 1.0, 1.0])
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assert_array_almost_equal(denomp.c, [1.0])
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nump, denomp = pade(an, 1, 2)
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assert_array_almost_equal(nump.c, [1.0/6, 2.0/3, 1.0])
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assert_array_almost_equal(denomp.c, [-1.0/3, 1.0])
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nump, denomp = pade(an, 2, 1)
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assert_array_almost_equal(nump.c, [1.0/3, 1.0])
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assert_array_almost_equal(denomp.c, [1.0/6, -2.0/3, 1.0])
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nump, denomp = pade(an, 3, 0)
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assert_array_almost_equal(nump.c, [1.0])
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assert_array_almost_equal(denomp.c, [-1.0/6, 0.5, -1.0, 1.0])
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# Testing reducing array
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nump, denomp = pade(an, 0, 2)
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assert_array_almost_equal(nump.c, [0.5, 1.0, 1.0])
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assert_array_almost_equal(denomp.c, [1.0])
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nump, denomp = pade(an, 1, 1)
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assert_array_almost_equal(nump.c, [1.0/2, 1.0])
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assert_array_almost_equal(denomp.c, [-1.0/2, 1.0])
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nump, denomp = pade(an, 2, 0)
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assert_array_almost_equal(nump.c, [1.0])
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assert_array_almost_equal(denomp.c, [1.0/2, -1.0, 1.0])
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