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| """Tests for hermite module. | |
| """ | |
| from functools import reduce | |
| import numpy as np | |
| import numpy.polynomial.hermite as herm | |
| from numpy.polynomial.polynomial import polyval | |
| from numpy.testing import ( | |
| assert_almost_equal, assert_raises, assert_equal, assert_, | |
| ) | |
| H0 = np.array([1]) | |
| H1 = np.array([0, 2]) | |
| H2 = np.array([-2, 0, 4]) | |
| H3 = np.array([0, -12, 0, 8]) | |
| H4 = np.array([12, 0, -48, 0, 16]) | |
| H5 = np.array([0, 120, 0, -160, 0, 32]) | |
| H6 = np.array([-120, 0, 720, 0, -480, 0, 64]) | |
| H7 = np.array([0, -1680, 0, 3360, 0, -1344, 0, 128]) | |
| H8 = np.array([1680, 0, -13440, 0, 13440, 0, -3584, 0, 256]) | |
| H9 = np.array([0, 30240, 0, -80640, 0, 48384, 0, -9216, 0, 512]) | |
| Hlist = [H0, H1, H2, H3, H4, H5, H6, H7, H8, H9] | |
| def trim(x): | |
| return herm.hermtrim(x, tol=1e-6) | |
| class TestConstants: | |
| def test_hermdomain(self): | |
| assert_equal(herm.hermdomain, [-1, 1]) | |
| def test_hermzero(self): | |
| assert_equal(herm.hermzero, [0]) | |
| def test_hermone(self): | |
| assert_equal(herm.hermone, [1]) | |
| def test_hermx(self): | |
| assert_equal(herm.hermx, [0, .5]) | |
| class TestArithmetic: | |
| x = np.linspace(-3, 3, 100) | |
| def test_hermadd(self): | |
| for i in range(5): | |
| for j in range(5): | |
| msg = f"At i={i}, j={j}" | |
| tgt = np.zeros(max(i, j) + 1) | |
| tgt[i] += 1 | |
| tgt[j] += 1 | |
| res = herm.hermadd([0]*i + [1], [0]*j + [1]) | |
| assert_equal(trim(res), trim(tgt), err_msg=msg) | |
| def test_hermsub(self): | |
| for i in range(5): | |
| for j in range(5): | |
| msg = f"At i={i}, j={j}" | |
| tgt = np.zeros(max(i, j) + 1) | |
| tgt[i] += 1 | |
| tgt[j] -= 1 | |
| res = herm.hermsub([0]*i + [1], [0]*j + [1]) | |
| assert_equal(trim(res), trim(tgt), err_msg=msg) | |
| def test_hermmulx(self): | |
| assert_equal(herm.hermmulx([0]), [0]) | |
| assert_equal(herm.hermmulx([1]), [0, .5]) | |
| for i in range(1, 5): | |
| ser = [0]*i + [1] | |
| tgt = [0]*(i - 1) + [i, 0, .5] | |
| assert_equal(herm.hermmulx(ser), tgt) | |
| def test_hermmul(self): | |
| # check values of result | |
| for i in range(5): | |
| pol1 = [0]*i + [1] | |
| val1 = herm.hermval(self.x, pol1) | |
| for j in range(5): | |
| msg = f"At i={i}, j={j}" | |
| pol2 = [0]*j + [1] | |
| val2 = herm.hermval(self.x, pol2) | |
| pol3 = herm.hermmul(pol1, pol2) | |
| val3 = herm.hermval(self.x, pol3) | |
| assert_(len(pol3) == i + j + 1, msg) | |
| assert_almost_equal(val3, val1*val2, err_msg=msg) | |
| def test_hermdiv(self): | |
| for i in range(5): | |
| for j in range(5): | |
| msg = f"At i={i}, j={j}" | |
| ci = [0]*i + [1] | |
| cj = [0]*j + [1] | |
| tgt = herm.hermadd(ci, cj) | |
| quo, rem = herm.hermdiv(tgt, ci) | |
| res = herm.hermadd(herm.hermmul(quo, ci), rem) | |
| assert_equal(trim(res), trim(tgt), err_msg=msg) | |
| def test_hermpow(self): | |
| for i in range(5): | |
| for j in range(5): | |
| msg = f"At i={i}, j={j}" | |
| c = np.arange(i + 1) | |
| tgt = reduce(herm.hermmul, [c]*j, np.array([1])) | |
| res = herm.hermpow(c, j) | |
| assert_equal(trim(res), trim(tgt), err_msg=msg) | |
| class TestEvaluation: | |
| # coefficients of 1 + 2*x + 3*x**2 | |
| c1d = np.array([2.5, 1., .75]) | |
| c2d = np.einsum('i,j->ij', c1d, c1d) | |
| c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d) | |
| # some random values in [-1, 1) | |
| x = np.random.random((3, 5))*2 - 1 | |
| y = polyval(x, [1., 2., 3.]) | |
| def test_hermval(self): | |
| #check empty input | |
| assert_equal(herm.hermval([], [1]).size, 0) | |
| #check normal input) | |
| x = np.linspace(-1, 1) | |
| y = [polyval(x, c) for c in Hlist] | |
| for i in range(10): | |
| msg = f"At i={i}" | |
| tgt = y[i] | |
| res = herm.hermval(x, [0]*i + [1]) | |
| assert_almost_equal(res, tgt, err_msg=msg) | |
| #check that shape is preserved | |
| for i in range(3): | |
| dims = [2]*i | |
| x = np.zeros(dims) | |
| assert_equal(herm.hermval(x, [1]).shape, dims) | |
| assert_equal(herm.hermval(x, [1, 0]).shape, dims) | |
| assert_equal(herm.hermval(x, [1, 0, 0]).shape, dims) | |
| def test_hermval2d(self): | |
| x1, x2, x3 = self.x | |
| y1, y2, y3 = self.y | |
| #test exceptions | |
| assert_raises(ValueError, herm.hermval2d, x1, x2[:2], self.c2d) | |
| #test values | |
| tgt = y1*y2 | |
| res = herm.hermval2d(x1, x2, self.c2d) | |
| assert_almost_equal(res, tgt) | |
| #test shape | |
| z = np.ones((2, 3)) | |
| res = herm.hermval2d(z, z, self.c2d) | |
| assert_(res.shape == (2, 3)) | |
| def test_hermval3d(self): | |
| x1, x2, x3 = self.x | |
| y1, y2, y3 = self.y | |
| #test exceptions | |
| assert_raises(ValueError, herm.hermval3d, x1, x2, x3[:2], self.c3d) | |
| #test values | |
| tgt = y1*y2*y3 | |
| res = herm.hermval3d(x1, x2, x3, self.c3d) | |
| assert_almost_equal(res, tgt) | |
| #test shape | |
| z = np.ones((2, 3)) | |
| res = herm.hermval3d(z, z, z, self.c3d) | |
| assert_(res.shape == (2, 3)) | |
| def test_hermgrid2d(self): | |
| x1, x2, x3 = self.x | |
| y1, y2, y3 = self.y | |
| #test values | |
| tgt = np.einsum('i,j->ij', y1, y2) | |
| res = herm.hermgrid2d(x1, x2, self.c2d) | |
| assert_almost_equal(res, tgt) | |
| #test shape | |
| z = np.ones((2, 3)) | |
| res = herm.hermgrid2d(z, z, self.c2d) | |
| assert_(res.shape == (2, 3)*2) | |
| def test_hermgrid3d(self): | |
| x1, x2, x3 = self.x | |
| y1, y2, y3 = self.y | |
| #test values | |
| tgt = np.einsum('i,j,k->ijk', y1, y2, y3) | |
| res = herm.hermgrid3d(x1, x2, x3, self.c3d) | |
| assert_almost_equal(res, tgt) | |
| #test shape | |
| z = np.ones((2, 3)) | |
| res = herm.hermgrid3d(z, z, z, self.c3d) | |
| assert_(res.shape == (2, 3)*3) | |
| class TestIntegral: | |
| def test_hermint(self): | |
| # check exceptions | |
| assert_raises(TypeError, herm.hermint, [0], .5) | |
| assert_raises(ValueError, herm.hermint, [0], -1) | |
| assert_raises(ValueError, herm.hermint, [0], 1, [0, 0]) | |
| assert_raises(ValueError, herm.hermint, [0], lbnd=[0]) | |
| assert_raises(ValueError, herm.hermint, [0], scl=[0]) | |
| assert_raises(TypeError, herm.hermint, [0], axis=.5) | |
| # test integration of zero polynomial | |
| for i in range(2, 5): | |
| k = [0]*(i - 2) + [1] | |
| res = herm.hermint([0], m=i, k=k) | |
| assert_almost_equal(res, [0, .5]) | |
| # check single integration with integration constant | |
| for i in range(5): | |
| scl = i + 1 | |
| pol = [0]*i + [1] | |
| tgt = [i] + [0]*i + [1/scl] | |
| hermpol = herm.poly2herm(pol) | |
| hermint = herm.hermint(hermpol, m=1, k=[i]) | |
| res = herm.herm2poly(hermint) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check single integration with integration constant and lbnd | |
| for i in range(5): | |
| scl = i + 1 | |
| pol = [0]*i + [1] | |
| hermpol = herm.poly2herm(pol) | |
| hermint = herm.hermint(hermpol, m=1, k=[i], lbnd=-1) | |
| assert_almost_equal(herm.hermval(-1, hermint), i) | |
| # check single integration with integration constant and scaling | |
| for i in range(5): | |
| scl = i + 1 | |
| pol = [0]*i + [1] | |
| tgt = [i] + [0]*i + [2/scl] | |
| hermpol = herm.poly2herm(pol) | |
| hermint = herm.hermint(hermpol, m=1, k=[i], scl=2) | |
| res = herm.herm2poly(hermint) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check multiple integrations with default k | |
| for i in range(5): | |
| for j in range(2, 5): | |
| pol = [0]*i + [1] | |
| tgt = pol[:] | |
| for k in range(j): | |
| tgt = herm.hermint(tgt, m=1) | |
| res = herm.hermint(pol, m=j) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check multiple integrations with defined k | |
| for i in range(5): | |
| for j in range(2, 5): | |
| pol = [0]*i + [1] | |
| tgt = pol[:] | |
| for k in range(j): | |
| tgt = herm.hermint(tgt, m=1, k=[k]) | |
| res = herm.hermint(pol, m=j, k=list(range(j))) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check multiple integrations with lbnd | |
| for i in range(5): | |
| for j in range(2, 5): | |
| pol = [0]*i + [1] | |
| tgt = pol[:] | |
| for k in range(j): | |
| tgt = herm.hermint(tgt, m=1, k=[k], lbnd=-1) | |
| res = herm.hermint(pol, m=j, k=list(range(j)), lbnd=-1) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check multiple integrations with scaling | |
| for i in range(5): | |
| for j in range(2, 5): | |
| pol = [0]*i + [1] | |
| tgt = pol[:] | |
| for k in range(j): | |
| tgt = herm.hermint(tgt, m=1, k=[k], scl=2) | |
| res = herm.hermint(pol, m=j, k=list(range(j)), scl=2) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| def test_hermint_axis(self): | |
| # check that axis keyword works | |
| c2d = np.random.random((3, 4)) | |
| tgt = np.vstack([herm.hermint(c) for c in c2d.T]).T | |
| res = herm.hermint(c2d, axis=0) | |
| assert_almost_equal(res, tgt) | |
| tgt = np.vstack([herm.hermint(c) for c in c2d]) | |
| res = herm.hermint(c2d, axis=1) | |
| assert_almost_equal(res, tgt) | |
| tgt = np.vstack([herm.hermint(c, k=3) for c in c2d]) | |
| res = herm.hermint(c2d, k=3, axis=1) | |
| assert_almost_equal(res, tgt) | |
| class TestDerivative: | |
| def test_hermder(self): | |
| # check exceptions | |
| assert_raises(TypeError, herm.hermder, [0], .5) | |
| assert_raises(ValueError, herm.hermder, [0], -1) | |
| # check that zeroth derivative does nothing | |
| for i in range(5): | |
| tgt = [0]*i + [1] | |
| res = herm.hermder(tgt, m=0) | |
| assert_equal(trim(res), trim(tgt)) | |
| # check that derivation is the inverse of integration | |
| for i in range(5): | |
| for j in range(2, 5): | |
| tgt = [0]*i + [1] | |
| res = herm.hermder(herm.hermint(tgt, m=j), m=j) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| # check derivation with scaling | |
| for i in range(5): | |
| for j in range(2, 5): | |
| tgt = [0]*i + [1] | |
| res = herm.hermder(herm.hermint(tgt, m=j, scl=2), m=j, scl=.5) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| def test_hermder_axis(self): | |
| # check that axis keyword works | |
| c2d = np.random.random((3, 4)) | |
| tgt = np.vstack([herm.hermder(c) for c in c2d.T]).T | |
| res = herm.hermder(c2d, axis=0) | |
| assert_almost_equal(res, tgt) | |
| tgt = np.vstack([herm.hermder(c) for c in c2d]) | |
| res = herm.hermder(c2d, axis=1) | |
| assert_almost_equal(res, tgt) | |
| class TestVander: | |
| # some random values in [-1, 1) | |
| x = np.random.random((3, 5))*2 - 1 | |
| def test_hermvander(self): | |
| # check for 1d x | |
| x = np.arange(3) | |
| v = herm.hermvander(x, 3) | |
| assert_(v.shape == (3, 4)) | |
| for i in range(4): | |
| coef = [0]*i + [1] | |
| assert_almost_equal(v[..., i], herm.hermval(x, coef)) | |
| # check for 2d x | |
| x = np.array([[1, 2], [3, 4], [5, 6]]) | |
| v = herm.hermvander(x, 3) | |
| assert_(v.shape == (3, 2, 4)) | |
| for i in range(4): | |
| coef = [0]*i + [1] | |
| assert_almost_equal(v[..., i], herm.hermval(x, coef)) | |
| def test_hermvander2d(self): | |
| # also tests hermval2d for non-square coefficient array | |
| x1, x2, x3 = self.x | |
| c = np.random.random((2, 3)) | |
| van = herm.hermvander2d(x1, x2, [1, 2]) | |
| tgt = herm.hermval2d(x1, x2, c) | |
| res = np.dot(van, c.flat) | |
| assert_almost_equal(res, tgt) | |
| # check shape | |
| van = herm.hermvander2d([x1], [x2], [1, 2]) | |
| assert_(van.shape == (1, 5, 6)) | |
| def test_hermvander3d(self): | |
| # also tests hermval3d for non-square coefficient array | |
| x1, x2, x3 = self.x | |
| c = np.random.random((2, 3, 4)) | |
| van = herm.hermvander3d(x1, x2, x3, [1, 2, 3]) | |
| tgt = herm.hermval3d(x1, x2, x3, c) | |
| res = np.dot(van, c.flat) | |
| assert_almost_equal(res, tgt) | |
| # check shape | |
| van = herm.hermvander3d([x1], [x2], [x3], [1, 2, 3]) | |
| assert_(van.shape == (1, 5, 24)) | |
| class TestFitting: | |
| def test_hermfit(self): | |
| def f(x): | |
| return x*(x - 1)*(x - 2) | |
| def f2(x): | |
| return x**4 + x**2 + 1 | |
| # Test exceptions | |
| assert_raises(ValueError, herm.hermfit, [1], [1], -1) | |
| assert_raises(TypeError, herm.hermfit, [[1]], [1], 0) | |
| assert_raises(TypeError, herm.hermfit, [], [1], 0) | |
| assert_raises(TypeError, herm.hermfit, [1], [[[1]]], 0) | |
| assert_raises(TypeError, herm.hermfit, [1, 2], [1], 0) | |
| assert_raises(TypeError, herm.hermfit, [1], [1, 2], 0) | |
| assert_raises(TypeError, herm.hermfit, [1], [1], 0, w=[[1]]) | |
| assert_raises(TypeError, herm.hermfit, [1], [1], 0, w=[1, 1]) | |
| assert_raises(ValueError, herm.hermfit, [1], [1], [-1,]) | |
| assert_raises(ValueError, herm.hermfit, [1], [1], [2, -1, 6]) | |
| assert_raises(TypeError, herm.hermfit, [1], [1], []) | |
| # Test fit | |
| x = np.linspace(0, 2) | |
| y = f(x) | |
| # | |
| coef3 = herm.hermfit(x, y, 3) | |
| assert_equal(len(coef3), 4) | |
| assert_almost_equal(herm.hermval(x, coef3), y) | |
| coef3 = herm.hermfit(x, y, [0, 1, 2, 3]) | |
| assert_equal(len(coef3), 4) | |
| assert_almost_equal(herm.hermval(x, coef3), y) | |
| # | |
| coef4 = herm.hermfit(x, y, 4) | |
| assert_equal(len(coef4), 5) | |
| assert_almost_equal(herm.hermval(x, coef4), y) | |
| coef4 = herm.hermfit(x, y, [0, 1, 2, 3, 4]) | |
| assert_equal(len(coef4), 5) | |
| assert_almost_equal(herm.hermval(x, coef4), y) | |
| # check things still work if deg is not in strict increasing | |
| coef4 = herm.hermfit(x, y, [2, 3, 4, 1, 0]) | |
| assert_equal(len(coef4), 5) | |
| assert_almost_equal(herm.hermval(x, coef4), y) | |
| # | |
| coef2d = herm.hermfit(x, np.array([y, y]).T, 3) | |
| assert_almost_equal(coef2d, np.array([coef3, coef3]).T) | |
| coef2d = herm.hermfit(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 | |
| y[0::2] = 0 | |
| wcoef3 = herm.hermfit(x, yw, 3, w=w) | |
| assert_almost_equal(wcoef3, coef3) | |
| wcoef3 = herm.hermfit(x, yw, [0, 1, 2, 3], w=w) | |
| assert_almost_equal(wcoef3, coef3) | |
| # | |
| wcoef2d = herm.hermfit(x, np.array([yw, yw]).T, 3, w=w) | |
| assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T) | |
| wcoef2d = herm.hermfit(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(herm.hermfit(x, x, 1), [0, .5]) | |
| assert_almost_equal(herm.hermfit(x, x, [0, 1]), [0, .5]) | |
| # test fitting only even Legendre polynomials | |
| x = np.linspace(-1, 1) | |
| y = f2(x) | |
| coef1 = herm.hermfit(x, y, 4) | |
| assert_almost_equal(herm.hermval(x, coef1), y) | |
| coef2 = herm.hermfit(x, y, [0, 2, 4]) | |
| assert_almost_equal(herm.hermval(x, coef2), y) | |
| assert_almost_equal(coef1, coef2) | |
| class TestCompanion: | |
| def test_raises(self): | |
| assert_raises(ValueError, herm.hermcompanion, []) | |
| assert_raises(ValueError, herm.hermcompanion, [1]) | |
| def test_dimensions(self): | |
| for i in range(1, 5): | |
| coef = [0]*i + [1] | |
| assert_(herm.hermcompanion(coef).shape == (i, i)) | |
| def test_linear_root(self): | |
| assert_(herm.hermcompanion([1, 2])[0, 0] == -.25) | |
| class TestGauss: | |
| def test_100(self): | |
| x, w = herm.hermgauss(100) | |
| # test orthogonality. Note that the results need to be normalized, | |
| # otherwise the huge values that can arise from fast growing | |
| # functions like Laguerre can be very confusing. | |
| v = herm.hermvander(x, 99) | |
| vv = np.dot(v.T * w, v) | |
| vd = 1/np.sqrt(vv.diagonal()) | |
| vv = vd[:, None] * vv * vd | |
| assert_almost_equal(vv, np.eye(100)) | |
| # check that the integral of 1 is correct | |
| tgt = np.sqrt(np.pi) | |
| assert_almost_equal(w.sum(), tgt) | |
| class TestMisc: | |
| def test_hermfromroots(self): | |
| res = herm.hermfromroots([]) | |
| 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]) | |
| pol = herm.hermfromroots(roots) | |
| res = herm.hermval(roots, pol) | |
| tgt = 0 | |
| assert_(len(pol) == i + 1) | |
| assert_almost_equal(herm.herm2poly(pol)[-1], 1) | |
| assert_almost_equal(res, tgt) | |
| def test_hermroots(self): | |
| assert_almost_equal(herm.hermroots([1]), []) | |
| assert_almost_equal(herm.hermroots([1, 1]), [-.5]) | |
| for i in range(2, 5): | |
| tgt = np.linspace(-1, 1, i) | |
| res = herm.hermroots(herm.hermfromroots(tgt)) | |
| assert_almost_equal(trim(res), trim(tgt)) | |
| def test_hermtrim(self): | |
| coef = [2, -1, 1, 0] | |
| # Test exceptions | |
| assert_raises(ValueError, herm.hermtrim, coef, -1) | |
| # Test results | |
| assert_equal(herm.hermtrim(coef), coef[:-1]) | |
| assert_equal(herm.hermtrim(coef, 1), coef[:-3]) | |
| assert_equal(herm.hermtrim(coef, 2), [0]) | |
| def test_hermline(self): | |
| assert_equal(herm.hermline(3, 4), [3, 2]) | |
| def test_herm2poly(self): | |
| for i in range(10): | |
| assert_almost_equal(herm.herm2poly([0]*i + [1]), Hlist[i]) | |
| def test_poly2herm(self): | |
| for i in range(10): | |
| assert_almost_equal(herm.poly2herm(Hlist[i]), [0]*i + [1]) | |
| def test_weight(self): | |
| x = np.linspace(-5, 5, 11) | |
| tgt = np.exp(-x**2) | |
| res = herm.hermweight(x) | |
| assert_almost_equal(res, tgt) | |