pyerrors/tests/fits_test.py

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import autograd.numpy as np
import math
import scipy.optimize
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from scipy.odr import ODR, Model, RealData
from scipy.linalg import cholesky
from scipy.stats import norm
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import pyerrors as pe
import pytest
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np.random.seed(0)
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def test_least_squares():
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dim = 10 + int(30 * np.random.rand())
x = np.arange(dim)
y = 2 * np.exp(-0.06 * x) + np.random.normal(0.0, 0.15, dim)
yerr = 0.1 + 0.1 * np.random.rand(dim)
oy = []
for i, item in enumerate(x):
oy.append(pe.pseudo_Obs(y[i], yerr[i], str(i)))
def f(x, a, b):
return a * np.exp(-b * x)
popt, pcov = scipy.optimize.curve_fit(f, x, y, sigma=[o.dvalue for o in oy], absolute_sigma=True)
def func(a, x):
y = a[0] * np.exp(-a[1] * x)
return y
out = pe.least_squares(x, oy, func, expected_chisquare=True, resplot=True, qqplot=True)
beta = out.fit_parameters
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for i in range(2):
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beta[i].gamma_method(S=1.0)
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assert math.isclose(beta[i].value, popt[i], abs_tol=1e-5)
assert math.isclose(pcov[i, i], beta[i].dvalue ** 2, abs_tol=1e-3)
assert math.isclose(pe.covariance(beta[0], beta[1]), pcov[0, 1], abs_tol=1e-3)
chi2_pyerrors = np.sum(((f(x, *[o.value for o in beta]) - y) / yerr) ** 2) / (len(x) - 2)
chi2_scipy = np.sum(((f(x, *popt) - y) / yerr) ** 2) / (len(x) - 2)
assert math.isclose(chi2_pyerrors, chi2_scipy, abs_tol=1e-10)
out = pe.least_squares(x, oy, func, const_par=[beta[1]])
assert((out.fit_parameters[0] - beta[0]).is_zero())
assert((out.fit_parameters[1] - beta[1]).is_zero())
oyc = []
for i, item in enumerate(x):
oyc.append(pe.cov_Obs(y[i], yerr[i]**2, 'cov' + str(i)))
outc = pe.least_squares(x, oyc, func)
betac = outc.fit_parameters
for i in range(2):
betac[i].gamma_method(S=1.0)
assert math.isclose(betac[i].value, popt[i], abs_tol=1e-5)
assert math.isclose(pcov[i, i], betac[i].dvalue ** 2, abs_tol=1e-3)
assert math.isclose(pe.covariance(betac[0], betac[1]), pcov[0, 1], abs_tol=1e-3)
num_samples = 400
N = 10
x = norm.rvs(size=(N, num_samples))
r = np.zeros((N, N))
for i in range(N):
for j in range(N):
r[i, j] = np.exp(-0.1 * np.fabs(i - j))
errl = np.sqrt([3.4, 2.5, 3.6, 2.8, 4.2, 4.7, 4.9, 5.1, 3.2, 4.2])
errl *= 4
for i in range(N):
for j in range(N):
r[i, j] *= errl[i] * errl[j]
c = cholesky(r, lower=True)
y = np.dot(c, x)
x = np.arange(N)
for linear in [True, False]:
data = []
for i in range(N):
if linear:
data.append(pe.Obs([[i + 1 + o for o in y[i]]], ['ens']))
else:
data.append(pe.Obs([[np.exp(-(i + 1)) + np.exp(-(i + 1)) * o for o in y[i]]], ['ens']))
[o.gamma_method() for o in data]
if linear:
def fitf(p, x):
return p[1] + p[0] * x
else:
def fitf(p, x):
return p[1] * np.exp(-p[0] * x)
fitp = pe.least_squares(x, data, fitf, expected_chisquare=True)
fitpc = pe.least_squares(x, data, fitf, correlated_fit=True)
for i in range(2):
diff = fitp[i] - fitpc[i]
diff.gamma_method()
assert(diff.is_zero_within_error(sigma=1.5))
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def test_total_least_squares():
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dim = 10 + int(30 * np.random.rand())
x = np.arange(dim) + np.random.normal(0.0, 0.15, dim)
xerr = 0.1 + 0.1 * np.random.rand(dim)
y = 2 * np.exp(-0.06 * x) + np.random.normal(0.0, 0.15, dim)
yerr = 0.1 + 0.1 * np.random.rand(dim)
ox = []
for i, item in enumerate(x):
ox.append(pe.pseudo_Obs(x[i], xerr[i], str(i)))
oy = []
for i, item in enumerate(x):
oy.append(pe.pseudo_Obs(y[i], yerr[i], str(i)))
def f(x, a, b):
return a * np.exp(-b * x)
def func(a, x):
y = a[0] * np.exp(-a[1] * x)
return y
data = RealData([o.value for o in ox], [o.value for o in oy], sx=[o.dvalue for o in ox], sy=[o.dvalue for o in oy])
model = Model(func)
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odr = ODR(data, model, [0, 0], partol=np.finfo(np.float64).eps)
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odr.set_job(fit_type=0, deriv=1)
output = odr.run()
out = pe.total_least_squares(ox, oy, func, expected_chisquare=True)
beta = out.fit_parameters
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for i in range(2):
beta[i].gamma_method(S=1.0)
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assert math.isclose(beta[i].value, output.beta[i], rel_tol=1e-5)
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assert math.isclose(output.cov_beta[i, i], beta[i].dvalue ** 2, rel_tol=2.5e-1), str(output.cov_beta[i, i]) + ' ' + str(beta[i].dvalue ** 2)
assert math.isclose(pe.covariance(beta[0], beta[1]), output.cov_beta[0, 1], rel_tol=2.5e-1)
out = pe.total_least_squares(ox, oy, func, const_par=[beta[1]])
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diff = out.fit_parameters[0] - beta[0]
assert(diff / beta[0] < 1e-3 * beta[0].dvalue)
assert((out.fit_parameters[1] - beta[1]).is_zero())
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oxc = []
for i, item in enumerate(x):
oxc.append(pe.cov_Obs(x[i], xerr[i]**2, 'covx' + str(i)))
oyc = []
for i, item in enumerate(x):
oyc.append(pe.cov_Obs(y[i], yerr[i]**2, 'covy' + str(i)))
outc = pe.total_least_squares(oxc, oyc, func)
betac = outc.fit_parameters
for i in range(2):
betac[i].gamma_method(S=1.0)
assert math.isclose(betac[i].value, output.beta[i], rel_tol=1e-3)
assert math.isclose(output.cov_beta[i, i], betac[i].dvalue ** 2, rel_tol=2.5e-1), str(output.cov_beta[i, i]) + ' ' + str(betac[i].dvalue ** 2)
assert math.isclose(pe.covariance(betac[0], betac[1]), output.cov_beta[0, 1], rel_tol=2.5e-1)
outc = pe.total_least_squares(oxc, oyc, func, const_par=[betac[1]])
diffc = outc.fit_parameters[0] - betac[0]
assert(diffc / betac[0] < 1e-3 * betac[0].dvalue)
assert((outc.fit_parameters[1] - betac[1]).is_zero())
outc = pe.total_least_squares(oxc, oy, func)
betac = outc.fit_parameters
for i in range(2):
betac[i].gamma_method(S=1.0)
assert math.isclose(betac[i].value, output.beta[i], rel_tol=1e-3)
assert math.isclose(output.cov_beta[i, i], betac[i].dvalue ** 2, rel_tol=2.5e-1), str(output.cov_beta[i, i]) + ' ' + str(betac[i].dvalue ** 2)
assert math.isclose(pe.covariance(betac[0], betac[1]), output.cov_beta[0, 1], rel_tol=2.5e-1)
outc = pe.total_least_squares(oxc, oy, func, const_par=[betac[1]])
diffc = outc.fit_parameters[0] - betac[0]
assert(diffc / betac[0] < 1e-3 * betac[0].dvalue)
assert((outc.fit_parameters[1] - betac[1]).is_zero())
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def test_odr_derivatives():
x = []
y = []
x_err = 0.01
y_err = 0.01
for n in np.arange(1, 9, 2):
loc_xvalue = n + np.random.normal(0.0, x_err)
x.append(pe.pseudo_Obs(loc_xvalue, x_err, str(n)))
y.append(pe.pseudo_Obs((lambda x: x ** 2 - 1)(loc_xvalue) +
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np.random.normal(0.0, y_err), y_err, str(n)))
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def func(a, x):
return a[0] + a[1] * x ** 2
out = pe.total_least_squares(x, y, func)
fit1 = out.fit_parameters
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with pytest.warns(DeprecationWarning):
tfit = pe.fits.fit_general(x, y, func, base_step=0.1, step_ratio=1.1, num_steps=20)
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assert np.abs(np.max(np.array(list(fit1[1].deltas.values()))
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- np.array(list(tfit[1].deltas.values())))) < 10e-8
def test_r_value_persistence():
def f(a, x):
return a[0] + a[1] * x
a = pe.pseudo_Obs(1.1, .1, 'a')
assert np.isclose(a.value, a.r_values['a'])
a_2 = a ** 2
assert np.isclose(a_2.value, a_2.r_values['a'])
b = pe.pseudo_Obs(2.1, .2, 'b')
y = [a, b]
[o.gamma_method() for o in y]
fitp = pe.fits.least_squares([1, 2], y, f)
assert np.isclose(fitp[0].value, fitp[0].r_values['a'])
assert np.isclose(fitp[0].value, fitp[0].r_values['b'])
assert np.isclose(fitp[1].value, fitp[1].r_values['a'])
assert np.isclose(fitp[1].value, fitp[1].r_values['b'])
fitp = pe.fits.total_least_squares(y, y, f)
assert np.isclose(fitp[0].value, fitp[0].r_values['a'])
assert np.isclose(fitp[0].value, fitp[0].r_values['b'])
assert np.isclose(fitp[1].value, fitp[1].r_values['a'])
assert np.isclose(fitp[1].value, fitp[1].r_values['b'])
fitp = pe.fits.least_squares([1, 2], y, f, priors=y)
assert np.isclose(fitp[0].value, fitp[0].r_values['a'])
assert np.isclose(fitp[0].value, fitp[0].r_values['b'])
assert np.isclose(fitp[1].value, fitp[1].r_values['a'])
assert np.isclose(fitp[1].value, fitp[1].r_values['b'])