ADD:
ruff for code formatting BIC statistic AND BIC test implemented test_distributions.py for test new created dists with pytest REFACTOR: k_gen pdf changed from 2 params to generalized
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174
etc/tests/test_distributions.py
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174
etc/tests/test_distributions.py
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import numpy as np
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import pytest
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import matplotlib.pyplot as plt
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import sys
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import os
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sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
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from tools.distributions import k_dist
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X = np.linspace(0.01, 10.0, 500)
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# ── k_dist unit tests ────────────────────────────────────────────────────────
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class TestKDistPdf:
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def test_pdf_is_positive_for_valid_input(self):
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"""PDF must be strictly positive for x > 0 and valid parameters."""
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vals = k_dist.pdf(X, mu=1.0, alpha=2.0, beta=2.0)
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assert np.all(vals > 0)
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def test_pdf_integrates_to_one(self):
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"""Numerical integral of PDF over a wide domain should be ≈ 1."""
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x_fine = np.linspace(1e-4, 200.0, 100_000)
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integral = np.trapezoid(k_dist.pdf(x_fine, mu=1.0, alpha=2.0, beta=2.0), x_fine)
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assert pytest.approx(integral, abs=1e-3) == 1.0
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def test_mean_equals_mu(self):
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"""Numerical mean of distribution should match the mu parameter."""
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x_grid = np.linspace(1e-4, 500.0, 200_000)
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for mu in [0.5, 1.0, 3.0]:
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mean_num = np.trapezoid(x_grid * k_dist.pdf(x_grid, mu=mu, alpha=2.0, beta=3.0), x_grid)
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assert pytest.approx(mean_num, rel=1e-2) == mu
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def test_logpdf_equals_log_pdf(self):
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"""logpdf must equal log(pdf) for numerical consistency."""
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x_test = np.linspace(0.1, 5.0, 20)
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log_via_pdf = np.log(k_dist.pdf(x_test, mu=1.0, alpha=2.0, beta=3.0))
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log_direct = k_dist.logpdf(x_test, mu=1.0, alpha=2.0, beta=3.0)
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np.testing.assert_allclose(log_direct, log_via_pdf, rtol=1e-6)
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def test_argcheck_rejects_non_positive_mu(self):
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"""mu <= 0 must not produce a valid (positive-finite) PDF value."""
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val = k_dist.pdf(1.0, mu=-1.0, alpha=2.0, beta=2.0)
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assert not (np.isfinite(val) and val > 0)
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def test_argcheck_rejects_non_positive_alpha(self):
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"""alpha <= 0 must not produce a valid (positive-finite) PDF value."""
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val = k_dist.pdf(1.0, mu=1.0, alpha=-1.0, beta=2.0)
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assert not (np.isfinite(val) and val > 0)
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def test_argcheck_rejects_non_positive_beta(self):
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"""beta <= 0 must not produce a valid (positive-finite) PDF value."""
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val = k_dist.pdf(1.0, mu=1.0, alpha=2.0, beta=-1.0)
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assert not (np.isfinite(val) and val > 0)
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def test_larger_alpha_shifts_mass_right(self):
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"""Increasing alpha (with mu and beta fixed) shifts probability mass to the right."""
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x_grid = np.linspace(1e-4, 50.0, 20_000)
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mean_low = np.trapezoid(x_grid * k_dist.pdf(x_grid, mu=2.0, alpha=0.5, beta=2.0), x_grid)
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mean_high = np.trapezoid(x_grid * k_dist.pdf(x_grid, mu=2.0, alpha=4.0, beta=2.0), x_grid)
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# Both should be close to mu=2.0; variance changes but mean is fixed
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assert pytest.approx(mean_low, rel=5e-2) == 2.0
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assert pytest.approx(mean_high, rel=5e-2) == 2.0
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def test_symmetry_in_alpha_beta(self):
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"""PDF is symmetric in alpha and beta: swapping them gives the same PDF."""
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x_test = np.linspace(0.1, 5.0, 20)
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pdf_ab = k_dist.pdf(x_test, mu=1.0, alpha=2.0, beta=3.0)
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pdf_ba = k_dist.pdf(x_test, mu=1.0, alpha=3.0, beta=2.0)
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np.testing.assert_allclose(pdf_ab, pdf_ba, rtol=1e-6)
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# ── Parametric curve plots ───────────────────────────────────────────────────
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def plot_k_dist_varying_alpha(save_path=None):
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"""Plot generalized K-distribution PDF curves for several values of alpha."""
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alpha_values = [0.5, 1.0, 2.0, 4.0, 8.0]
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x = np.linspace(1e-4, 15.0, 1000)
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fig, ax = plt.subplots(figsize=(8, 5))
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for alpha in alpha_values:
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ax.plot(x, k_dist.pdf(x, mu=2.0, alpha=alpha, beta=2.0), label=f"alpha={alpha}")
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ax.set_xlabel("x")
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ax.set_ylabel("PDF")
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ax.set_title("Generalized K distribution — varying alpha (mu=2.0, beta=2.0 fixed)")
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ax.legend()
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ax.set_ylim(bottom=0)
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fig.tight_layout()
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if save_path:
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fig.savefig(save_path, dpi=150)
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return fig
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def plot_k_dist_varying_mu(save_path=None):
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"""Plot generalized K-distribution PDF curves for several values of mu."""
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mu_values = [0.5, 1.0, 2.0, 4.0, 8.0]
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x = np.linspace(1e-4, 30.0, 1000)
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fig, ax = plt.subplots(figsize=(8, 5))
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for mu in mu_values:
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ax.plot(x, k_dist.pdf(x, mu=mu, alpha=2.0, beta=2.0), label=f"mu={mu}")
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ax.set_xlabel("x")
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ax.set_ylabel("PDF")
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ax.set_title("Generalized K distribution — varying mu (alpha=2.0, beta=2.0 fixed)")
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ax.legend()
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ax.set_ylim(bottom=0)
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fig.tight_layout()
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if save_path:
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fig.savefig(save_path, dpi=150)
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return fig
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def plot_k_dist_varying_beta(save_path=None):
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"""Plot generalized K-distribution PDF curves for several values of beta."""
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beta_values = [0.5, 1.0, 2.0, 4.0, 8.0]
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x = np.linspace(1e-4, 15.0, 1000)
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fig, ax = plt.subplots(figsize=(8, 5))
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for beta in beta_values:
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ax.plot(x, k_dist.pdf(x, mu=2.0, alpha=2.0, beta=beta), label=f"beta={beta}")
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ax.set_xlabel("x")
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ax.set_ylabel("PDF")
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ax.set_title("Generalized K distribution — varying beta (mu=2.0, alpha=2.0 fixed)")
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ax.legend()
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ax.set_ylim(bottom=0)
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fig.tight_layout()
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if save_path:
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fig.savefig(save_path, dpi=150)
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return fig
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# ── Test: plots are generated without errors ─────────────────────────────────
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class TestKDistPlots:
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def test_plot_varying_alpha_runs_without_error(self, tmp_path):
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"""Curve plot varying alpha must complete and save a file."""
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out = tmp_path / "k_dist_alpha.png"
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fig = plot_k_dist_varying_alpha(save_path=str(out))
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assert out.exists()
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plt.close(fig)
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def test_plot_varying_mu_runs_without_error(self, tmp_path):
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"""Curve plot varying mu must complete and save a file."""
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out = tmp_path / "k_dist_mu.png"
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fig = plot_k_dist_varying_mu(save_path=str(out))
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assert out.exists()
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plt.close(fig)
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def test_plot_varying_beta_runs_without_error(self, tmp_path):
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"""Curve plot varying beta must complete and save a file."""
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out = tmp_path / "k_dist_beta.png"
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fig = plot_k_dist_varying_beta(save_path=str(out))
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assert out.exists()
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plt.close(fig)
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# ── Entry-point: run plots interactively ─────────────────────────────────────
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if __name__ == "__main__":
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plot_k_dist_varying_alpha()
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plot_k_dist_varying_mu()
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plot_k_dist_varying_beta()
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plt.show()
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@@ -6,7 +6,7 @@ import os
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sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
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from tools.statistics import aic_statistic
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from tools.statistics import aic_statistic, bic_statistic
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from fitting.fitter import Fitter
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@@ -110,3 +110,101 @@ class TestAicStatisticInFitter:
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f.validate(n_mc_samples=99)
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assert f["gamma"].test_result is not None
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assert f["expon"].test_result is not None
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# ── bic_statistic unit tests ──────────────────────────────────────────────────
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class TestBicStatistic:
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def _fitted_dist(self, dist, data, **kwargs):
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"""Return a frozen distribution fitted to data."""
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params = dist.fit(data, **kwargs)
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return dist(*params)
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def test_returns_float(self):
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frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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result = bic_statistic(frozen, GAMMA_DATA, axis=0)
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assert isinstance(float(result), float)
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def test_formula_correct(self):
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"""BIC = ln(n)*k - 2*log_likelihood."""
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frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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n = len(GAMMA_DATA)
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k = len(frozen.args)
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log_likelihood = np.sum(frozen.logpdf(GAMMA_DATA), axis=0)
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expected = np.log(n) * k - 2 * log_likelihood
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assert pytest.approx(bic_statistic(frozen, GAMMA_DATA, axis=0)) == expected
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def test_penalises_more_parameters(self):
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"""gamma (3 params) should have higher BIC penalty term than expon (2 params)."""
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gamma_frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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expon_frozen = self._fitted_dist(expon, GAMMA_DATA, floc=0)
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n = len(GAMMA_DATA)
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assert np.log(n) * len(gamma_frozen.args) > np.log(n) * len(expon_frozen.args)
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def test_better_fit_has_lower_bic(self):
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"""Gamma fitted to gamma data should have lower BIC than normal fitted to gamma data."""
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gamma_frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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norm_frozen = self._fitted_dist(norm, GAMMA_DATA)
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bic_gamma = bic_statistic(gamma_frozen, GAMMA_DATA, axis=0)
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bic_norm = bic_statistic(norm_frozen, GAMMA_DATA, axis=0)
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assert bic_gamma < bic_norm
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def test_works_with_axis_none(self):
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frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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result = bic_statistic(frozen, GAMMA_DATA, axis=None)
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assert np.isfinite(result)
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def test_result_is_finite(self):
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frozen = self._fitted_dist(gamma, GAMMA_DATA, floc=0)
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assert np.isfinite(bic_statistic(frozen, GAMMA_DATA, axis=0))
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# ── Integration: bic_statistic as callable in Fitter ─────────────────────────
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class TestBicStatisticInFitter:
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def test_fitter_accepts_bic_callable(self):
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f = Fitter([gamma], statistic_method=bic_statistic, gamma_params={"floc": 0})
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f.fit(GAMMA_DATA)
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f.validate(n_mc_samples=99)
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assert f["gamma"].test_result is not None
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def test_fitter_bic_statistic_is_finite(self):
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f = Fitter([gamma], statistic_method=bic_statistic, gamma_params={"floc": 0})
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f.fit(GAMMA_DATA)
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f.validate(n_mc_samples=99)
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assert np.isfinite(f["gamma"].gof_statistic)
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def test_fitter_bic_pvalue_in_range(self):
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f = Fitter([gamma], statistic_method=bic_statistic, gamma_params={"floc": 0})
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f.fit(GAMMA_DATA)
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f.validate(n_mc_samples=99)
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pval = f["gamma"].pvalue
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assert 0.0 <= pval <= 1.0
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def test_fitter_bic_vs_ad_different_statistic_values(self):
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"""BIC and AD statistics should differ numerically."""
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f_bic = Fitter(
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[gamma], statistic_method=bic_statistic, gamma_params={"floc": 0}
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)
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f_ad = Fitter([gamma], statistic_method="ad", gamma_params={"floc": 0})
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f_bic.fit(GAMMA_DATA)
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f_ad.fit(GAMMA_DATA)
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f_bic.validate(n_mc_samples=99)
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f_ad.validate(n_mc_samples=99)
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assert f_bic["gamma"].gof_statistic != pytest.approx(
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f_ad["gamma"].gof_statistic
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)
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def test_fitter_bic_multiple_distributions(self):
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f = Fitter(
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[gamma, expon],
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statistic_method=bic_statistic,
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gamma_params={"floc": 0},
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expon_params={"floc": 0},
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)
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f.fit(GAMMA_DATA)
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f.validate(n_mc_samples=99)
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assert f["gamma"].test_result is not None
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assert f["expon"].test_result is not None
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