97 lines
3.6 KiB
Python
97 lines
3.6 KiB
Python
"""
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GTSAM Copyright 2010-2019, Georgia Tech Research Corporation,
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Atlanta, Georgia 30332-0415
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All Rights Reserved
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See LICENSE for the license information
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Basis unit tests.
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Author: Frank Dellaert & Gerry Chen (Python)
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"""
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import unittest
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import numpy as np
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import gtsam
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from gtsam.utils.test_case import GtsamTestCase
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from gtsam.symbol_shorthand import B
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class TestBasis(GtsamTestCase):
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"""
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Tests FitBasis python binding for FourierBasis, Chebyshev1Basis, Chebyshev2Basis, and Chebyshev2.
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It tests FitBasis by fitting to a ground-truth function that can be represented exactly in
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the basis, then checking that the regression (fit result) matches the function. For the
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Chebyshev bases, the line y=x is used to generate the data while for Fourier, 0.7*cos(x) is
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used.
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"""
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def setUp(self):
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self.N = 2
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self.x = [0., 0.5, 0.75]
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self.interpx = np.linspace(0., 1., 10)
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self.noise = gtsam.noiseModel.Unit.Create(1)
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def evaluate(self, basis, fitparams, x):
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"""
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Until wrapper for Basis functors are ready,
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this is how to evaluate a basis function.
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"""
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return basis.WeightMatrix(self.N, x) @ fitparams
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def fit_basis_helper(self, fitter, basis, f=lambda x: x):
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"""Helper method to fit data to a specified fitter using a specified basis."""
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data = {x: f(x) for x in self.x}
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fit = fitter(data, self.noise, self.N)
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coeff = fit.parameters()
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interpy = self.evaluate(basis, coeff, self.interpx)
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return interpy
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def test_fit_basis_fourier(self):
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"""Fit a Fourier basis."""
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f = lambda x: 0.7 * np.cos(x)
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interpy = self.fit_basis_helper(gtsam.FitBasisFourierBasis,
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gtsam.FourierBasis, f)
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# test a basis by checking that the fit result matches the function at x-values interpx.
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np.testing.assert_almost_equal(interpy,
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np.array([f(x) for x in self.interpx]),
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decimal=7)
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def test_fit_basis_chebyshev1basis(self):
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"""Fit a Chebyshev1 basis."""
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f = lambda x: x
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interpy = self.fit_basis_helper(gtsam.FitBasisChebyshev1Basis,
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gtsam.Chebyshev1Basis, f)
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# test a basis by checking that the fit result matches the function at x-values interpx.
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np.testing.assert_almost_equal(interpy,
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np.array([f(x) for x in self.interpx]),
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decimal=7)
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def test_fit_basis_chebyshev2basis(self):
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"""Fit a Chebyshev2 basis."""
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f = lambda x: x
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interpy = self.fit_basis_helper(gtsam.FitBasisChebyshev2Basis,
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gtsam.Chebyshev2Basis)
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# test a basis by checking that the fit result matches the function at x-values interpx.
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np.testing.assert_almost_equal(interpy,
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np.array([f(x) for x in self.interpx]),
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decimal=7)
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def test_fit_basis_chebyshev2(self):
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"""Fit a Chebyshev2 pseudospectral basis."""
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f = lambda x: x
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interpy = self.fit_basis_helper(gtsam.FitBasisChebyshev2,
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gtsam.Chebyshev2)
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# test a basis by checking that the fit result matches the function at x-values interpx.
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np.testing.assert_almost_equal(interpy,
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np.array([f(x) for x in self.interpx]),
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decimal=7)
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if __name__ == "__main__":
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unittest.main()
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