Python numpy.polynomial.legendre.legfit() Examples

The following are 2 code examples for showing how to use numpy.polynomial.legendre.legfit(). These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example.

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Example 1
Project: Computable   Author: ktraunmueller   File: test_legendre.py    License: MIT License 4 votes vote down vote up
def test_legfit(self) :
        def f(x) :
            return x*(x - 1)*(x - 2)

        # Test exceptions
        assert_raises(ValueError, leg.legfit, [1],    [1],     -1)
        assert_raises(TypeError,  leg.legfit, [[1]],  [1],      0)
        assert_raises(TypeError,  leg.legfit, [],     [1],      0)
        assert_raises(TypeError,  leg.legfit, [1],    [[[1]]],  0)
        assert_raises(TypeError,  leg.legfit, [1, 2], [1],      0)
        assert_raises(TypeError,  leg.legfit, [1],    [1, 2],   0)
        assert_raises(TypeError,  leg.legfit, [1],    [1],   0, w=[[1]])
        assert_raises(TypeError,  leg.legfit, [1],    [1],   0, w=[1, 1])

        # Test fit
        x = np.linspace(0, 2)
        y = f(x)
        #
        coef3 = leg.legfit(x, y, 3)
        assert_equal(len(coef3), 4)
        assert_almost_equal(leg.legval(x, coef3), y)
        #
        coef4 = leg.legfit(x, y, 4)
        assert_equal(len(coef4), 5)
        assert_almost_equal(leg.legval(x, coef4), y)
        #
        coef2d = leg.legfit(x, np.array([y, y]).T, 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 = leg.legfit(x, yw, 3, w=w)
        assert_almost_equal(wcoef3, coef3)
        #
        wcoef2d = leg.legfit(x, np.array([yw, yw]).T, 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(leg.legfit(x, x, 1), [0, 1]) 
Example 2
Project: ImageFusion   Author: pfchai   File: test_legendre.py    License: MIT License 4 votes vote down vote up
def test_legfit(self):
        def f(x):
            return x*(x - 1)*(x - 2)

        # Test exceptions
        assert_raises(ValueError, leg.legfit, [1], [1], -1)
        assert_raises(TypeError, leg.legfit, [[1]], [1], 0)
        assert_raises(TypeError, leg.legfit, [], [1], 0)
        assert_raises(TypeError, leg.legfit, [1], [[[1]]], 0)
        assert_raises(TypeError, leg.legfit, [1, 2], [1], 0)
        assert_raises(TypeError, leg.legfit, [1], [1, 2], 0)
        assert_raises(TypeError, leg.legfit, [1], [1], 0, w=[[1]])
        assert_raises(TypeError, leg.legfit, [1], [1], 0, w=[1, 1])

        # Test fit
        x = np.linspace(0, 2)
        y = f(x)
        #
        coef3 = leg.legfit(x, y, 3)
        assert_equal(len(coef3), 4)
        assert_almost_equal(leg.legval(x, coef3), y)
        #
        coef4 = leg.legfit(x, y, 4)
        assert_equal(len(coef4), 5)
        assert_almost_equal(leg.legval(x, coef4), y)
        #
        coef2d = leg.legfit(x, np.array([y, y]).T, 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 = leg.legfit(x, yw, 3, w=w)
        assert_almost_equal(wcoef3, coef3)
        #
        wcoef2d = leg.legfit(x, np.array([yw, yw]).T, 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(leg.legfit(x, x, 1), [0, 1])