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594 lines
20 KiB
Python
594 lines
20 KiB
Python
"""Tests for polynomial module.
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"""
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from __future__ import division, absolute_import, print_function
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from functools import reduce
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import numpy as np
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import numpy.polynomial.polynomial as poly
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from numpy.testing import (
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assert_almost_equal, assert_raises, assert_equal, assert_,
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assert_warns, assert_array_equal)
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def trim(x):
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return poly.polytrim(x, tol=1e-6)
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T0 = [1]
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T1 = [0, 1]
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T2 = [-1, 0, 2]
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T3 = [0, -3, 0, 4]
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T4 = [1, 0, -8, 0, 8]
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T5 = [0, 5, 0, -20, 0, 16]
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T6 = [-1, 0, 18, 0, -48, 0, 32]
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T7 = [0, -7, 0, 56, 0, -112, 0, 64]
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T8 = [1, 0, -32, 0, 160, 0, -256, 0, 128]
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T9 = [0, 9, 0, -120, 0, 432, 0, -576, 0, 256]
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Tlist = [T0, T1, T2, T3, T4, T5, T6, T7, T8, T9]
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class TestConstants(object):
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def test_polydomain(self):
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assert_equal(poly.polydomain, [-1, 1])
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def test_polyzero(self):
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assert_equal(poly.polyzero, [0])
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def test_polyone(self):
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assert_equal(poly.polyone, [1])
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def test_polyx(self):
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assert_equal(poly.polyx, [0, 1])
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class TestArithmetic(object):
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def test_polyadd(self):
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for i in range(5):
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for j in range(5):
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msg = "At i=%d, j=%d" % (i, j)
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tgt = np.zeros(max(i, j) + 1)
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tgt[i] += 1
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tgt[j] += 1
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res = poly.polyadd([0]*i + [1], [0]*j + [1])
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assert_equal(trim(res), trim(tgt), err_msg=msg)
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def test_polysub(self):
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for i in range(5):
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for j in range(5):
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msg = "At i=%d, j=%d" % (i, j)
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tgt = np.zeros(max(i, j) + 1)
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tgt[i] += 1
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tgt[j] -= 1
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res = poly.polysub([0]*i + [1], [0]*j + [1])
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assert_equal(trim(res), trim(tgt), err_msg=msg)
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def test_polymulx(self):
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assert_equal(poly.polymulx([0]), [0])
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assert_equal(poly.polymulx([1]), [0, 1])
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for i in range(1, 5):
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ser = [0]*i + [1]
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tgt = [0]*(i + 1) + [1]
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assert_equal(poly.polymulx(ser), tgt)
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def test_polymul(self):
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for i in range(5):
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for j in range(5):
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msg = "At i=%d, j=%d" % (i, j)
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tgt = np.zeros(i + j + 1)
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tgt[i + j] += 1
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res = poly.polymul([0]*i + [1], [0]*j + [1])
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assert_equal(trim(res), trim(tgt), err_msg=msg)
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def test_polydiv(self):
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# check zero division
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assert_raises(ZeroDivisionError, poly.polydiv, [1], [0])
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# check scalar division
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quo, rem = poly.polydiv([2], [2])
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assert_equal((quo, rem), (1, 0))
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quo, rem = poly.polydiv([2, 2], [2])
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assert_equal((quo, rem), ((1, 1), 0))
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# check rest.
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for i in range(5):
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for j in range(5):
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msg = "At i=%d, j=%d" % (i, j)
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ci = [0]*i + [1, 2]
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cj = [0]*j + [1, 2]
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tgt = poly.polyadd(ci, cj)
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quo, rem = poly.polydiv(tgt, ci)
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res = poly.polyadd(poly.polymul(quo, ci), rem)
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assert_equal(res, tgt, err_msg=msg)
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def test_polypow(self):
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for i in range(5):
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for j in range(5):
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msg = "At i=%d, j=%d" % (i, j)
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c = np.arange(i + 1)
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tgt = reduce(poly.polymul, [c]*j, np.array([1]))
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res = poly.polypow(c, j)
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assert_equal(trim(res), trim(tgt), err_msg=msg)
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class TestEvaluation(object):
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# coefficients of 1 + 2*x + 3*x**2
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c1d = np.array([1., 2., 3.])
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c2d = np.einsum('i,j->ij', c1d, c1d)
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c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
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# some random values in [-1, 1)
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x = np.random.random((3, 5))*2 - 1
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y = poly.polyval(x, [1., 2., 3.])
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def test_polyval(self):
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#check empty input
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assert_equal(poly.polyval([], [1]).size, 0)
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#check normal input)
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x = np.linspace(-1, 1)
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y = [x**i for i in range(5)]
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for i in range(5):
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tgt = y[i]
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res = poly.polyval(x, [0]*i + [1])
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assert_almost_equal(res, tgt)
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tgt = x*(x**2 - 1)
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res = poly.polyval(x, [0, -1, 0, 1])
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assert_almost_equal(res, tgt)
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#check that shape is preserved
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for i in range(3):
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dims = [2]*i
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x = np.zeros(dims)
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assert_equal(poly.polyval(x, [1]).shape, dims)
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assert_equal(poly.polyval(x, [1, 0]).shape, dims)
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assert_equal(poly.polyval(x, [1, 0, 0]).shape, dims)
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#check masked arrays are processed correctly
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mask = [False, True, False]
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mx = np.ma.array([1, 2, 3], mask=mask)
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res = np.polyval([7, 5, 3], mx)
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assert_array_equal(res.mask, mask)
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#check subtypes of ndarray are preserved
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class C(np.ndarray):
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pass
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cx = np.array([1, 2, 3]).view(C)
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assert_equal(type(np.polyval([2, 3, 4], cx)), C)
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def test_polyvalfromroots(self):
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# check exception for broadcasting x values over root array with
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# too few dimensions
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assert_raises(ValueError, poly.polyvalfromroots,
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[1], [1], tensor=False)
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# check empty input
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assert_equal(poly.polyvalfromroots([], [1]).size, 0)
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assert_(poly.polyvalfromroots([], [1]).shape == (0,))
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# check empty input + multidimensional roots
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assert_equal(poly.polyvalfromroots([], [[1] * 5]).size, 0)
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assert_(poly.polyvalfromroots([], [[1] * 5]).shape == (5, 0))
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# check scalar input
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assert_equal(poly.polyvalfromroots(1, 1), 0)
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assert_(poly.polyvalfromroots(1, np.ones((3, 3))).shape == (3,))
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# check normal input)
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x = np.linspace(-1, 1)
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y = [x**i for i in range(5)]
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for i in range(1, 5):
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tgt = y[i]
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res = poly.polyvalfromroots(x, [0]*i)
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assert_almost_equal(res, tgt)
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tgt = x*(x - 1)*(x + 1)
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res = poly.polyvalfromroots(x, [-1, 0, 1])
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assert_almost_equal(res, tgt)
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# check that shape is preserved
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for i in range(3):
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dims = [2]*i
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x = np.zeros(dims)
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assert_equal(poly.polyvalfromroots(x, [1]).shape, dims)
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assert_equal(poly.polyvalfromroots(x, [1, 0]).shape, dims)
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assert_equal(poly.polyvalfromroots(x, [1, 0, 0]).shape, dims)
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# check compatibility with factorization
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ptest = [15, 2, -16, -2, 1]
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r = poly.polyroots(ptest)
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x = np.linspace(-1, 1)
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assert_almost_equal(poly.polyval(x, ptest),
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poly.polyvalfromroots(x, r))
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# check multidimensional arrays of roots and values
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# check tensor=False
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rshape = (3, 5)
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x = np.arange(-3, 2)
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r = np.random.randint(-5, 5, size=rshape)
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res = poly.polyvalfromroots(x, r, tensor=False)
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tgt = np.empty(r.shape[1:])
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for ii in range(tgt.size):
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tgt[ii] = poly.polyvalfromroots(x[ii], r[:, ii])
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assert_equal(res, tgt)
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# check tensor=True
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x = np.vstack([x, 2*x])
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res = poly.polyvalfromroots(x, r, tensor=True)
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tgt = np.empty(r.shape[1:] + x.shape)
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for ii in range(r.shape[1]):
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for jj in range(x.shape[0]):
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tgt[ii, jj, :] = poly.polyvalfromroots(x[jj], r[:, ii])
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assert_equal(res, tgt)
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def test_polyval2d(self):
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x1, x2, x3 = self.x
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y1, y2, y3 = self.y
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#test exceptions
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assert_raises(ValueError, poly.polyval2d, x1, x2[:2], self.c2d)
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#test values
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tgt = y1*y2
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res = poly.polyval2d(x1, x2, self.c2d)
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assert_almost_equal(res, tgt)
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#test shape
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z = np.ones((2, 3))
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res = poly.polyval2d(z, z, self.c2d)
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assert_(res.shape == (2, 3))
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def test_polyval3d(self):
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x1, x2, x3 = self.x
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y1, y2, y3 = self.y
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#test exceptions
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assert_raises(ValueError, poly.polyval3d, x1, x2, x3[:2], self.c3d)
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#test values
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tgt = y1*y2*y3
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res = poly.polyval3d(x1, x2, x3, self.c3d)
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assert_almost_equal(res, tgt)
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#test shape
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z = np.ones((2, 3))
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res = poly.polyval3d(z, z, z, self.c3d)
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assert_(res.shape == (2, 3))
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def test_polygrid2d(self):
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x1, x2, x3 = self.x
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y1, y2, y3 = self.y
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#test values
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tgt = np.einsum('i,j->ij', y1, y2)
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res = poly.polygrid2d(x1, x2, self.c2d)
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assert_almost_equal(res, tgt)
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#test shape
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z = np.ones((2, 3))
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res = poly.polygrid2d(z, z, self.c2d)
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assert_(res.shape == (2, 3)*2)
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def test_polygrid3d(self):
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x1, x2, x3 = self.x
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y1, y2, y3 = self.y
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#test values
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tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
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res = poly.polygrid3d(x1, x2, x3, self.c3d)
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assert_almost_equal(res, tgt)
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#test shape
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z = np.ones((2, 3))
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res = poly.polygrid3d(z, z, z, self.c3d)
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assert_(res.shape == (2, 3)*3)
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class TestIntegral(object):
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def test_polyint(self):
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# check exceptions
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assert_raises(TypeError, poly.polyint, [0], .5)
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assert_raises(ValueError, poly.polyint, [0], -1)
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assert_raises(ValueError, poly.polyint, [0], 1, [0, 0])
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assert_raises(ValueError, poly.polyint, [0], lbnd=[0])
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assert_raises(ValueError, poly.polyint, [0], scl=[0])
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assert_raises(TypeError, poly.polyint, [0], axis=.5)
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with assert_warns(DeprecationWarning):
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poly.polyint([1, 1], 1.)
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# test integration of zero polynomial
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for i in range(2, 5):
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k = [0]*(i - 2) + [1]
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res = poly.polyint([0], m=i, k=k)
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assert_almost_equal(res, [0, 1])
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# check single integration with integration constant
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for i in range(5):
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scl = i + 1
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pol = [0]*i + [1]
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tgt = [i] + [0]*i + [1/scl]
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res = poly.polyint(pol, m=1, k=[i])
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assert_almost_equal(trim(res), trim(tgt))
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# check single integration with integration constant and lbnd
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for i in range(5):
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scl = i + 1
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pol = [0]*i + [1]
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res = poly.polyint(pol, m=1, k=[i], lbnd=-1)
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assert_almost_equal(poly.polyval(-1, res), i)
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# check single integration with integration constant and scaling
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for i in range(5):
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scl = i + 1
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pol = [0]*i + [1]
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tgt = [i] + [0]*i + [2/scl]
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res = poly.polyint(pol, m=1, k=[i], scl=2)
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assert_almost_equal(trim(res), trim(tgt))
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# check multiple integrations with default k
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for i in range(5):
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for j in range(2, 5):
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pol = [0]*i + [1]
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tgt = pol[:]
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for k in range(j):
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tgt = poly.polyint(tgt, m=1)
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res = poly.polyint(pol, m=j)
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assert_almost_equal(trim(res), trim(tgt))
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# check multiple integrations with defined k
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for i in range(5):
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for j in range(2, 5):
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pol = [0]*i + [1]
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tgt = pol[:]
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for k in range(j):
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tgt = poly.polyint(tgt, m=1, k=[k])
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res = poly.polyint(pol, m=j, k=list(range(j)))
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assert_almost_equal(trim(res), trim(tgt))
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# check multiple integrations with lbnd
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for i in range(5):
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for j in range(2, 5):
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pol = [0]*i + [1]
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tgt = pol[:]
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for k in range(j):
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tgt = poly.polyint(tgt, m=1, k=[k], lbnd=-1)
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res = poly.polyint(pol, m=j, k=list(range(j)), lbnd=-1)
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assert_almost_equal(trim(res), trim(tgt))
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# check multiple integrations with scaling
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for i in range(5):
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for j in range(2, 5):
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pol = [0]*i + [1]
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tgt = pol[:]
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for k in range(j):
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tgt = poly.polyint(tgt, m=1, k=[k], scl=2)
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res = poly.polyint(pol, m=j, k=list(range(j)), scl=2)
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assert_almost_equal(trim(res), trim(tgt))
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def test_polyint_axis(self):
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# check that axis keyword works
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c2d = np.random.random((3, 4))
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tgt = np.vstack([poly.polyint(c) for c in c2d.T]).T
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res = poly.polyint(c2d, axis=0)
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assert_almost_equal(res, tgt)
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tgt = np.vstack([poly.polyint(c) for c in c2d])
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res = poly.polyint(c2d, axis=1)
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assert_almost_equal(res, tgt)
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tgt = np.vstack([poly.polyint(c, k=3) for c in c2d])
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res = poly.polyint(c2d, k=3, axis=1)
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assert_almost_equal(res, tgt)
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class TestDerivative(object):
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def test_polyder(self):
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# check exceptions
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assert_raises(TypeError, poly.polyder, [0], .5)
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assert_raises(ValueError, poly.polyder, [0], -1)
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# check that zeroth derivative does nothing
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for i in range(5):
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tgt = [0]*i + [1]
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res = poly.polyder(tgt, m=0)
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assert_equal(trim(res), trim(tgt))
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# check that derivation is the inverse of integration
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for i in range(5):
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for j in range(2, 5):
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tgt = [0]*i + [1]
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res = poly.polyder(poly.polyint(tgt, m=j), m=j)
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assert_almost_equal(trim(res), trim(tgt))
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# check derivation with scaling
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for i in range(5):
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for j in range(2, 5):
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tgt = [0]*i + [1]
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res = poly.polyder(poly.polyint(tgt, m=j, scl=2), m=j, scl=.5)
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assert_almost_equal(trim(res), trim(tgt))
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def test_polyder_axis(self):
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# check that axis keyword works
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c2d = np.random.random((3, 4))
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tgt = np.vstack([poly.polyder(c) for c in c2d.T]).T
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res = poly.polyder(c2d, axis=0)
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assert_almost_equal(res, tgt)
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tgt = np.vstack([poly.polyder(c) for c in c2d])
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res = poly.polyder(c2d, axis=1)
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assert_almost_equal(res, tgt)
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class TestVander(object):
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# some random values in [-1, 1)
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x = np.random.random((3, 5))*2 - 1
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def test_polyvander(self):
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# check for 1d x
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x = np.arange(3)
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v = poly.polyvander(x, 3)
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assert_(v.shape == (3, 4))
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for i in range(4):
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coef = [0]*i + [1]
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assert_almost_equal(v[..., i], poly.polyval(x, coef))
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# check for 2d x
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x = np.array([[1, 2], [3, 4], [5, 6]])
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v = poly.polyvander(x, 3)
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assert_(v.shape == (3, 2, 4))
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for i in range(4):
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coef = [0]*i + [1]
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assert_almost_equal(v[..., i], poly.polyval(x, coef))
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def test_polyvander2d(self):
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# also tests polyval2d for non-square coefficient array
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x1, x2, x3 = self.x
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c = np.random.random((2, 3))
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van = poly.polyvander2d(x1, x2, [1, 2])
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tgt = poly.polyval2d(x1, x2, c)
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res = np.dot(van, c.flat)
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assert_almost_equal(res, tgt)
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|
|
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# check shape
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van = poly.polyvander2d([x1], [x2], [1, 2])
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assert_(van.shape == (1, 5, 6))
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|
|
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def test_polyvander3d(self):
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# also tests polyval3d for non-square coefficient array
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x1, x2, x3 = self.x
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c = np.random.random((2, 3, 4))
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van = poly.polyvander3d(x1, x2, x3, [1, 2, 3])
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tgt = poly.polyval3d(x1, x2, x3, c)
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res = np.dot(van, c.flat)
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assert_almost_equal(res, tgt)
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|
|
|
# check shape
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van = poly.polyvander3d([x1], [x2], [x3], [1, 2, 3])
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assert_(van.shape == (1, 5, 24))
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|
|
|
|
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class TestCompanion(object):
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|
|
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def test_raises(self):
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assert_raises(ValueError, poly.polycompanion, [])
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|
assert_raises(ValueError, poly.polycompanion, [1])
|
|
|
|
def test_dimensions(self):
|
|
for i in range(1, 5):
|
|
coef = [0]*i + [1]
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|
assert_(poly.polycompanion(coef).shape == (i, i))
|
|
|
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def test_linear_root(self):
|
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assert_(poly.polycompanion([1, 2])[0, 0] == -.5)
|
|
|
|
|
|
class TestMisc(object):
|
|
|
|
def test_polyfromroots(self):
|
|
res = poly.polyfromroots([])
|
|
assert_almost_equal(trim(res), [1])
|
|
for i in range(1, 5):
|
|
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
|
|
tgt = Tlist[i]
|
|
res = poly.polyfromroots(roots)*2**(i-1)
|
|
assert_almost_equal(trim(res), trim(tgt))
|
|
|
|
def test_polyroots(self):
|
|
assert_almost_equal(poly.polyroots([1]), [])
|
|
assert_almost_equal(poly.polyroots([1, 2]), [-.5])
|
|
for i in range(2, 5):
|
|
tgt = np.linspace(-1, 1, i)
|
|
res = poly.polyroots(poly.polyfromroots(tgt))
|
|
assert_almost_equal(trim(res), trim(tgt))
|
|
|
|
def test_polyfit(self):
|
|
def f(x):
|
|
return x*(x - 1)*(x - 2)
|
|
|
|
def f2(x):
|
|
return x**4 + x**2 + 1
|
|
|
|
# Test exceptions
|
|
assert_raises(ValueError, poly.polyfit, [1], [1], -1)
|
|
assert_raises(TypeError, poly.polyfit, [[1]], [1], 0)
|
|
assert_raises(TypeError, poly.polyfit, [], [1], 0)
|
|
assert_raises(TypeError, poly.polyfit, [1], [[[1]]], 0)
|
|
assert_raises(TypeError, poly.polyfit, [1, 2], [1], 0)
|
|
assert_raises(TypeError, poly.polyfit, [1], [1, 2], 0)
|
|
assert_raises(TypeError, poly.polyfit, [1], [1], 0, w=[[1]])
|
|
assert_raises(TypeError, poly.polyfit, [1], [1], 0, w=[1, 1])
|
|
assert_raises(ValueError, poly.polyfit, [1], [1], [-1,])
|
|
assert_raises(ValueError, poly.polyfit, [1], [1], [2, -1, 6])
|
|
assert_raises(TypeError, poly.polyfit, [1], [1], [])
|
|
|
|
# Test fit
|
|
x = np.linspace(0, 2)
|
|
y = f(x)
|
|
#
|
|
coef3 = poly.polyfit(x, y, 3)
|
|
assert_equal(len(coef3), 4)
|
|
assert_almost_equal(poly.polyval(x, coef3), y)
|
|
coef3 = poly.polyfit(x, y, [0, 1, 2, 3])
|
|
assert_equal(len(coef3), 4)
|
|
assert_almost_equal(poly.polyval(x, coef3), y)
|
|
#
|
|
coef4 = poly.polyfit(x, y, 4)
|
|
assert_equal(len(coef4), 5)
|
|
assert_almost_equal(poly.polyval(x, coef4), y)
|
|
coef4 = poly.polyfit(x, y, [0, 1, 2, 3, 4])
|
|
assert_equal(len(coef4), 5)
|
|
assert_almost_equal(poly.polyval(x, coef4), y)
|
|
#
|
|
coef2d = poly.polyfit(x, np.array([y, y]).T, 3)
|
|
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
|
|
coef2d = poly.polyfit(x, np.array([y, y]).T, [0, 1, 2, 3])
|
|
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
|
|
# test weighting
|
|
w = np.zeros_like(x)
|
|
yw = y.copy()
|
|
w[1::2] = 1
|
|
yw[0::2] = 0
|
|
wcoef3 = poly.polyfit(x, yw, 3, w=w)
|
|
assert_almost_equal(wcoef3, coef3)
|
|
wcoef3 = poly.polyfit(x, yw, [0, 1, 2, 3], w=w)
|
|
assert_almost_equal(wcoef3, coef3)
|
|
#
|
|
wcoef2d = poly.polyfit(x, np.array([yw, yw]).T, 3, w=w)
|
|
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
|
|
wcoef2d = poly.polyfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
|
|
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
|
|
# test scaling with complex values x points whose square
|
|
# is zero when summed.
|
|
x = [1, 1j, -1, -1j]
|
|
assert_almost_equal(poly.polyfit(x, x, 1), [0, 1])
|
|
assert_almost_equal(poly.polyfit(x, x, [0, 1]), [0, 1])
|
|
# test fitting only even Polyendre polynomials
|
|
x = np.linspace(-1, 1)
|
|
y = f2(x)
|
|
coef1 = poly.polyfit(x, y, 4)
|
|
assert_almost_equal(poly.polyval(x, coef1), y)
|
|
coef2 = poly.polyfit(x, y, [0, 2, 4])
|
|
assert_almost_equal(poly.polyval(x, coef2), y)
|
|
assert_almost_equal(coef1, coef2)
|
|
|
|
def test_polytrim(self):
|
|
coef = [2, -1, 1, 0]
|
|
|
|
# Test exceptions
|
|
assert_raises(ValueError, poly.polytrim, coef, -1)
|
|
|
|
# Test results
|
|
assert_equal(poly.polytrim(coef), coef[:-1])
|
|
assert_equal(poly.polytrim(coef, 1), coef[:-3])
|
|
assert_equal(poly.polytrim(coef, 2), [0])
|
|
|
|
def test_polyline(self):
|
|
assert_equal(poly.polyline(3, 4), [3, 4])
|