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1407 lines
43 KiB
C
1407 lines
43 KiB
C
/* Copyright (c) 2018-2020, The Tor Project, Inc. */
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/* See LICENSE for licensing information */
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/**
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* \file test_prob_distr.c
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* \brief Test probability distributions.
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* \detail
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*
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* For each probability distribution we do two kinds of tests:
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*
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* a) We do numerical deterministic testing of their cdf/icdf/sf/isf functions
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* and the various relationships between them for each distribution. We also
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* do deterministic tests on their sampling functions. Test vectors for
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* these tests were computed from alternative implementations and were
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* eyeballed to make sure they make sense
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* (e.g. src/test/prob_distr_mpfr_ref.c computes logit(p) using GNU mpfr
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* with 200-bit precision and is then tested in test_logit_logistic()).
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*
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* b) We do stochastic hypothesis testing (G-test) to ensure that sampling from
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* the given distributions is distributed properly. The stochastic tests are
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* slow and their false positive rate is not well suited for CI, so they are
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* currently disabled-by-default and put into 'tests-slow'.
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*/
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#define PROB_DISTR_PRIVATE
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#include "orconfig.h"
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#include "test/test.h"
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#include "core/or/or.h"
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#include "lib/math/prob_distr.h"
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#include "lib/math/fp.h"
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#include "lib/crypt_ops/crypto_rand.h"
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#include "test/rng_test_helpers.h"
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#include <float.h>
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#include <math.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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/**
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* Return floor(d) converted to size_t, as a workaround for complaints
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* under -Wbad-function-cast for (size_t)floor(d).
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*/
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static size_t
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floor_to_size_t(double d)
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{
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double integral_d = floor(d);
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return (size_t)integral_d;
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}
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/**
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* Return ceil(d) converted to size_t, as a workaround for complaints
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* under -Wbad-function-cast for (size_t)ceil(d).
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*/
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static size_t
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ceil_to_size_t(double d)
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{
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double integral_d = ceil(d);
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return (size_t)integral_d;
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}
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/*
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* Geometric(p) distribution, supported on {1, 2, 3, ...}.
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*
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* Compute the probability mass function Geom(n; p) of the number of
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* trials before the first success when success has probability p.
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*/
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static double
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logpmf_geometric(unsigned n, double p)
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{
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/* This is actually a check against 1, but we do >= so that the compiler
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does not raise a -Wfloat-equal */
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if (p >= 1) {
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if (n == 1)
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return 0;
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else
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return -HUGE_VAL;
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}
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return (n - 1)*log1p(-p) + log(p);
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}
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/**
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* Compute the logistic function, translated in output by 1/2:
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* logistichalf(x) = logistic(x) - 1/2. Well-conditioned on the entire
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* real plane, with maximum condition number 1 at 0.
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*
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* This implementation gives relative error bounded by 5 eps.
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*/
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static double
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logistichalf(double x)
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{
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/*
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* Rewrite this with the identity
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*
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* 1/(1 + e^{-x}) - 1/2
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* = (1 - 1/2 - e^{-x}/2)/(1 + e^{-x})
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* = (1/2 - e^{-x}/2)/(1 + e^{-x})
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* = (1 - e^{-x})/[2 (1 + e^{-x})]
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* = -(e^{-x} - 1)/[2 (1 + e^{-x})],
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*
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* which we can evaluate by -expm1(-x)/[2 (1 + exp(-x))].
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*
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* Suppose exp has error d0, + has error d1, expm1 has error
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* d2, and / has error d3, so we evaluate
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*
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* -(1 + d2) (1 + d3) (e^{-x} - 1)
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* / [2 (1 + d1) (1 + (1 + d0) e^{-x})].
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*
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* In the denominator,
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*
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* 1 + (1 + d0) e^{-x}
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* = 1 + e^{-x} + d0 e^{-x}
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* = (1 + e^{-x}) (1 + d0 e^{-x}/(1 + e^{-x})),
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*
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* so the relative error of the numerator is
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*
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* d' = d2 + d3 + d2 d3,
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* and of the denominator,
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* d'' = d1 + d0 e^{-x}/(1 + e^{-x}) + d0 d1 e^{-x}/(1 + e^{-x})
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* = d1 + d0 L(-x) + d0 d1 L(-x),
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*
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* where L(-x) is logistic(-x). By Lemma 1 the relative error
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* of the quotient is bounded by
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*
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* 2|d2 + d3 + d2 d3 - d1 - d0 L(x) + d0 d1 L(x)|,
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*
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* Since 0 < L(x) < 1, this is bounded by
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*
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* 2|d2| + 2|d3| + 2|d2 d3| + 2|d1| + 2|d0| + 2|d0 d1|
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* <= 4 eps + 2 eps^2.
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*/
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if (x < log(DBL_EPSILON/8)) {
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/*
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* Avoid overflow in e^{-x}. When x < log(eps/4), we
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* we further have x < logit(eps/4), so that
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* logistic(x) < eps/4. Hence the relative error of
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* logistic(x) - 1/2 from -1/2 is bounded by eps/2, and
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* so the relative error of -1/2 from logistic(x) - 1/2
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* is bounded by eps.
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*/
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return -0.5;
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} else {
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return -expm1(-x)/(2*(1 + exp(-x)));
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}
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}
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/**
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* Compute the log of the sum of the exps. Caller should arrange the
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* array in descending order to minimize error because I don't want to
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* deal with using temporary space and the one caller in this file
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* arranges that anyway.
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*
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* Warning: This implementation does not handle infinite or NaN inputs
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* sensibly, because I don't need that here at the moment. (NaN, or
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* -inf and +inf together, should yield NaN; +inf and finite should
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* yield +inf; otherwise all -inf should be ignored because exp(-inf) =
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* 0.)
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*/
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static double
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logsumexp(double *A, size_t n)
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{
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double maximum, sum;
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size_t i;
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if (n == 0)
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return log(0);
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maximum = A[0];
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for (i = 1; i < n; i++) {
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if (A[i] > maximum)
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maximum = A[i];
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}
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sum = 0;
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for (i = n; i --> 0;)
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sum += exp(A[i] - maximum);
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return log(sum) + maximum;
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}
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/**
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* Compute log(1 - e^x). Defined only for negative x so that e^x < 1.
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* This is the complement of a probability in log space.
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*/
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static double
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log1mexp(double x)
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{
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/*
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* We want to compute log on [0, 1/2) but log1p on [1/2, +inf),
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* so partition x at -log(2) = log(1/2).
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*/
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if (-log(2) < x)
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return log(-expm1(x));
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else
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return log1p(-exp(x));
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}
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/*
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* Tests of numerical errors in computing logit, logistic, and the
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* various cdfs, sfs, icdfs, and isfs.
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*/
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#define arraycount(A) (sizeof(A)/sizeof(A[0]))
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/** Return relative error between <b>actual</b> and <b>expected</b>.
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* Special cases: If <b>expected</b> is zero or infinite, return 1 if
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* <b>actual</b> is equal to <b>expected</b> and 0 if not, since the
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* usual notion of relative error is undefined but we only use this
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* for testing relerr(e, a) <= bound. If either is NaN, return NaN,
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* which has the property that NaN <= bound is false no matter what
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* bound is.
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*
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* Beware: if you test !(relerr(e, a) > bound), then then the result
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* is true when a is NaN because NaN > bound is false too. See
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* CHECK_RELERR for correct use to decide when to report failure.
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*/
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static double
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relerr(double expected, double actual)
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{
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/*
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* To silence -Wfloat-equal, we have to test for equality using
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* inequalities: we have (fabs(expected) <= 0) iff (expected == 0),
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* and (actual <= expected && actual >= expected) iff actual ==
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* expected whether expected is zero or infinite.
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*/
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if (fabs(expected) <= 0 || tor_isinf(expected)) {
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if (actual <= expected && actual >= expected)
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return 0;
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else
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return 1;
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} else {
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return fabs((expected - actual)/expected);
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}
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}
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/** Check that relative error of <b>expected</b> and <b>actual</b> is within
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* <b>relerr_bound</b>. Caller must arrange to have i and relerr_bound in
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* scope. */
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#define CHECK_RELERR(expected, actual) do { \
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double check_expected = (expected); \
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double check_actual = (actual); \
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const char *str_expected = #expected; \
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const char *str_actual = #actual; \
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double check_relerr = relerr(expected, actual); \
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if (!(relerr(check_expected, check_actual) <= relerr_bound)) { \
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log_warn(LD_GENERAL, "%s:%d: case %u: relerr(%s=%.17e, %s=%.17e)" \
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" = %.17e > %.17e\n", \
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__func__, __LINE__, (unsigned) i, \
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str_expected, check_expected, \
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str_actual, check_actual, \
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check_relerr, relerr_bound); \
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ok = false; \
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} \
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} while (0)
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/* Check that a <= b.
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* Caller must arrange to have i in scope. */
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#define CHECK_LE(a, b) do { \
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double check_a = (a); \
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double check_b = (b); \
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const char *str_a = #a; \
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const char *str_b = #b; \
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if (!(check_a <= check_b)) { \
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log_warn(LD_GENERAL, "%s:%d: case %u: %s=%.17e > %s=%.17e\n", \
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__func__, __LINE__, (unsigned) i, \
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str_a, check_a, str_b, check_b); \
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ok = false; \
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} \
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} while (0)
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/**
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* Test the logit and logistic functions. Confirm that they agree with
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* the cdf, sf, icdf, and isf of the standard Logistic distribution.
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* Confirm that the sampler for the standard logistic distribution maps
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* [0, 1] into the right subinterval for the inverse transform, for
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* this implementation.
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*/
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static void
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test_logit_logistic(void *arg)
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{
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(void) arg;
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static const struct {
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double x; /* x = logit(p) */
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double p; /* p = logistic(x) */
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double phalf; /* p - 1/2 = logistic(x) - 1/2 */
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} cases[] = {
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{ -HUGE_VAL, 0, -0.5 },
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{ -1000, 0, -0.5 },
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{ -710, 4.47628622567513e-309, -0.5 },
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{ -708, 3.307553003638408e-308, -0.5 },
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{ -2, .11920292202211755, -.3807970779778824 },
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{ -1.0000001, .2689414017088022, -.23105859829119776 },
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{ -1, .2689414213699951, -.23105857863000487 },
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{ -0.9999999, .26894144103118883, -.2310585589688111 },
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/* see src/test/prob_distr_mpfr_ref.c for computation */
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{ -4.000000000537333e-5, .49999, -1.0000000000010001e-5 },
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{ -4.000000000533334e-5, .49999, -.00001 },
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{ -4.000000108916878e-9, .499999999, -1.0000000272292198e-9 },
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{ -4e-9, .499999999, -1e-9 },
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{ -4e-16, .5, -1e-16 },
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{ -4e-300, .5, -1e-300 },
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{ 0, .5, 0 },
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{ 4e-300, .5, 1e-300 },
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{ 4e-16, .5, 1e-16 },
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{ 3.999999886872274e-9, .500000001, 9.999999717180685e-10 },
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{ 4e-9, .500000001, 1e-9 },
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{ 4.0000000005333336e-5, .50001, .00001 },
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{ 8.000042667076272e-3, .502, .002 },
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{ 0.9999999, .7310585589688111, .2310585589688111 },
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{ 1, .7310585786300049, .23105857863000487 },
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{ 1.0000001, .7310585982911977, .23105859829119774 },
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{ 2, .8807970779778823, .3807970779778824 },
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{ 708, 1, .5 },
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{ 710, 1, .5 },
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{ 1000, 1, .5 },
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{ HUGE_VAL, 1, .5 },
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};
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double relerr_bound = 3e-15; /* >10eps */
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size_t i;
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bool ok = true;
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for (i = 0; i < arraycount(cases); i++) {
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double x = cases[i].x;
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double p = cases[i].p;
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double phalf = cases[i].phalf;
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/*
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* cdf is logistic, icdf is logit, and symmetry for
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* sf/isf.
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*/
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CHECK_RELERR(logistic(x), cdf_logistic(x, 0, 1));
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CHECK_RELERR(logistic(-x), sf_logistic(x, 0, 1));
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CHECK_RELERR(logit(p), icdf_logistic(p, 0, 1));
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CHECK_RELERR(-logit(p), isf_logistic(p, 0, 1));
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CHECK_RELERR(cdf_logistic(x, 0, 1), cdf_logistic(x*2, 0, 2));
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CHECK_RELERR(sf_logistic(x, 0, 1), sf_logistic(x*2, 0, 2));
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CHECK_RELERR(icdf_logistic(p, 0, 1), icdf_logistic(p, 0, 2)/2);
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CHECK_RELERR(isf_logistic(p, 0, 1), isf_logistic(p, 0, 2)/2);
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CHECK_RELERR(cdf_logistic(x, 0, 1), cdf_logistic(x/2, 0, .5));
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CHECK_RELERR(sf_logistic(x, 0, 1), sf_logistic(x/2, 0, .5));
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CHECK_RELERR(icdf_logistic(p, 0, 1), icdf_logistic(p, 0,.5)*2);
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CHECK_RELERR(isf_logistic(p, 0, 1), isf_logistic(p, 0, .5)*2);
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CHECK_RELERR(cdf_logistic(x, 0, 1), cdf_logistic(x*2 + 1, 1, 2));
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CHECK_RELERR(sf_logistic(x, 0, 1), sf_logistic(x*2 + 1, 1, 2));
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/*
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* For p near 0 and p near 1/2, the arithmetic of
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* translating by 1 loses precision.
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*/
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if (fabs(p) > DBL_EPSILON && fabs(p) < 0.4) {
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CHECK_RELERR(icdf_logistic(p, 0, 1),
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(icdf_logistic(p, 1, 2) - 1)/2);
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CHECK_RELERR(isf_logistic(p, 0, 1),
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(isf_logistic(p, 1, 2) - 1)/2);
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}
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CHECK_RELERR(p, logistic(x));
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CHECK_RELERR(phalf, logistichalf(x));
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/*
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* On the interior floating-point numbers, either logit or
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* logithalf had better give the correct answer.
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*
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* For probabilities near 0, we can get much finer resolution with
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* logit, and for probabilities near 1/2, we can get much finer
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* resolution with logithalf by representing them using p - 1/2.
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*
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* E.g., we can write -.00001 for phalf, and .49999 for p, but the
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* difference 1/2 - .00001 gives 1.0000000000010001e-5 in binary64
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* arithmetic. So test logit(.49999) which should give the same
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* answer as logithalf(-1.0000000000010001e-5), namely
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* -4.000000000537333e-5, and also test logithalf(-.00001) which
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* gives -4.000000000533334e-5 instead -- but don't expect
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* logit(.49999) to give -4.000000000533334e-5 even though it looks
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* like 1/2 - .00001.
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*
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* A naive implementation of logit will just use log(p/(1 - p)) and
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* give the answer -4.000000000551673e-05 for .49999, which is
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* wrong in a lot of digits, which happens because log is
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* ill-conditioned near 1 and thus amplifies whatever relative
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* error we made in computing p/(1 - p).
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*/
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if ((0 < p && p < 1) || tor_isinf(x)) {
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if (phalf >= p - 0.5 && phalf <= p - 0.5)
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CHECK_RELERR(x, logit(p));
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if (p >= 0.5 + phalf && p <= 0.5 + phalf)
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CHECK_RELERR(x, logithalf(phalf));
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}
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CHECK_RELERR(-phalf, logistichalf(-x));
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if (fabs(phalf) < 0.5 || tor_isinf(x))
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CHECK_RELERR(-x, logithalf(-phalf));
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if (p < 1 || tor_isinf(x)) {
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CHECK_RELERR(1 - p, logistic(-x));
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if (p > .75 || tor_isinf(x))
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CHECK_RELERR(-x, logit(1 - p));
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} else {
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CHECK_LE(logistic(-x), 1e-300);
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}
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}
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for (i = 0; i <= 100; i++) {
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double p0 = (double)i/100;
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CHECK_RELERR(logit(p0/(1 + M_E)), sample_logistic(0, 0, p0));
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CHECK_RELERR(-logit(p0/(1 + M_E)), sample_logistic(1, 0, p0));
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CHECK_RELERR(logithalf(p0*(0.5 - 1/(1 + M_E))),
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sample_logistic(0, 1, p0));
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CHECK_RELERR(-logithalf(p0*(0.5 - 1/(1 + M_E))),
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sample_logistic(1, 1, p0));
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}
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if (!ok)
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printf("fail logit/logistic / logistic cdf/sf\n");
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tt_assert(ok);
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done:
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;
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}
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/**
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* Test the cdf, sf, icdf, and isf of the LogLogistic distribution.
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*/
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static void
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test_log_logistic(void *arg)
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{
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(void) arg;
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static const struct {
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/* x is a point in the support of the LogLogistic distribution */
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double x;
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/* 'p' is the probability that a random variable X for a given LogLogistic
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* probability ditribution will take value less-or-equal to x */
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double p;
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/* 'np' is the probability that a random variable X for a given LogLogistic
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|
* probability distribution will take value greater-or-equal to x. */
|
|
double np;
|
|
} cases[] = {
|
|
{ 0, 0, 1 },
|
|
{ 1e-300, 1e-300, 1 },
|
|
{ 1e-17, 1e-17, 1 },
|
|
{ 1e-15, 1e-15, .999999999999999 },
|
|
{ .1, .09090909090909091, .90909090909090909 },
|
|
{ .25, .2, .8 },
|
|
{ .5, .33333333333333333, .66666666666666667 },
|
|
{ .75, .42857142857142855, .5714285714285714 },
|
|
{ .9999, .49997499874993756, .5000250012500626 },
|
|
{ .99999999, .49999999749999996, .5000000025 },
|
|
{ .999999999999999, .49999999999999994, .5000000000000002 },
|
|
{ 1, .5, .5 },
|
|
};
|
|
double relerr_bound = 3e-15;
|
|
size_t i;
|
|
bool ok = true;
|
|
|
|
for (i = 0; i < arraycount(cases); i++) {
|
|
double x = cases[i].x;
|
|
double p = cases[i].p;
|
|
double np = cases[i].np;
|
|
|
|
CHECK_RELERR(p, cdf_log_logistic(x, 1, 1));
|
|
CHECK_RELERR(p, cdf_log_logistic(x/2, .5, 1));
|
|
CHECK_RELERR(p, cdf_log_logistic(x*2, 2, 1));
|
|
CHECK_RELERR(p, cdf_log_logistic(sqrt(x), 1, 2));
|
|
CHECK_RELERR(p, cdf_log_logistic(sqrt(x)/2, .5, 2));
|
|
CHECK_RELERR(p, cdf_log_logistic(sqrt(x)*2, 2, 2));
|
|
if (2*sqrt(DBL_MIN) < x) {
|
|
CHECK_RELERR(p, cdf_log_logistic(x*x, 1, .5));
|
|
CHECK_RELERR(p, cdf_log_logistic(x*x/2, .5, .5));
|
|
CHECK_RELERR(p, cdf_log_logistic(x*x*2, 2, .5));
|
|
}
|
|
|
|
CHECK_RELERR(np, sf_log_logistic(x, 1, 1));
|
|
CHECK_RELERR(np, sf_log_logistic(x/2, .5, 1));
|
|
CHECK_RELERR(np, sf_log_logistic(x*2, 2, 1));
|
|
CHECK_RELERR(np, sf_log_logistic(sqrt(x), 1, 2));
|
|
CHECK_RELERR(np, sf_log_logistic(sqrt(x)/2, .5, 2));
|
|
CHECK_RELERR(np, sf_log_logistic(sqrt(x)*2, 2, 2));
|
|
if (2*sqrt(DBL_MIN) < x) {
|
|
CHECK_RELERR(np, sf_log_logistic(x*x, 1, .5));
|
|
CHECK_RELERR(np, sf_log_logistic(x*x/2, .5, .5));
|
|
CHECK_RELERR(np, sf_log_logistic(x*x*2, 2, .5));
|
|
}
|
|
|
|
CHECK_RELERR(np, cdf_log_logistic(1/x, 1, 1));
|
|
CHECK_RELERR(np, cdf_log_logistic(1/(2*x), .5, 1));
|
|
CHECK_RELERR(np, cdf_log_logistic(2/x, 2, 1));
|
|
CHECK_RELERR(np, cdf_log_logistic(1/sqrt(x), 1, 2));
|
|
CHECK_RELERR(np, cdf_log_logistic(1/(2*sqrt(x)), .5, 2));
|
|
CHECK_RELERR(np, cdf_log_logistic(2/sqrt(x), 2, 2));
|
|
if (2*sqrt(DBL_MIN) < x && x < 1/(2*sqrt(DBL_MIN))) {
|
|
CHECK_RELERR(np, cdf_log_logistic(1/(x*x), 1, .5));
|
|
CHECK_RELERR(np, cdf_log_logistic(1/(2*x*x), .5, .5));
|
|
CHECK_RELERR(np, cdf_log_logistic(2/(x*x), 2, .5));
|
|
}
|
|
|
|
CHECK_RELERR(p, sf_log_logistic(1/x, 1, 1));
|
|
CHECK_RELERR(p, sf_log_logistic(1/(2*x), .5, 1));
|
|
CHECK_RELERR(p, sf_log_logistic(2/x, 2, 1));
|
|
CHECK_RELERR(p, sf_log_logistic(1/sqrt(x), 1, 2));
|
|
CHECK_RELERR(p, sf_log_logistic(1/(2*sqrt(x)), .5, 2));
|
|
CHECK_RELERR(p, sf_log_logistic(2/sqrt(x), 2, 2));
|
|
if (2*sqrt(DBL_MIN) < x && x < 1/(2*sqrt(DBL_MIN))) {
|
|
CHECK_RELERR(p, sf_log_logistic(1/(x*x), 1, .5));
|
|
CHECK_RELERR(p, sf_log_logistic(1/(2*x*x), .5, .5));
|
|
CHECK_RELERR(p, sf_log_logistic(2/(x*x), 2, .5));
|
|
}
|
|
|
|
CHECK_RELERR(x, icdf_log_logistic(p, 1, 1));
|
|
CHECK_RELERR(x/2, icdf_log_logistic(p, .5, 1));
|
|
CHECK_RELERR(x*2, icdf_log_logistic(p, 2, 1));
|
|
CHECK_RELERR(x, icdf_log_logistic(p, 1, 1));
|
|
CHECK_RELERR(sqrt(x)/2, icdf_log_logistic(p, .5, 2));
|
|
CHECK_RELERR(sqrt(x)*2, icdf_log_logistic(p, 2, 2));
|
|
CHECK_RELERR(sqrt(x), icdf_log_logistic(p, 1, 2));
|
|
CHECK_RELERR(x*x/2, icdf_log_logistic(p, .5, .5));
|
|
CHECK_RELERR(x*x*2, icdf_log_logistic(p, 2, .5));
|
|
|
|
if (np < .9) {
|
|
CHECK_RELERR(x, isf_log_logistic(np, 1, 1));
|
|
CHECK_RELERR(x/2, isf_log_logistic(np, .5, 1));
|
|
CHECK_RELERR(x*2, isf_log_logistic(np, 2, 1));
|
|
CHECK_RELERR(sqrt(x), isf_log_logistic(np, 1, 2));
|
|
CHECK_RELERR(sqrt(x)/2, isf_log_logistic(np, .5, 2));
|
|
CHECK_RELERR(sqrt(x)*2, isf_log_logistic(np, 2, 2));
|
|
CHECK_RELERR(x*x, isf_log_logistic(np, 1, .5));
|
|
CHECK_RELERR(x*x/2, isf_log_logistic(np, .5, .5));
|
|
CHECK_RELERR(x*x*2, isf_log_logistic(np, 2, .5));
|
|
|
|
CHECK_RELERR(1/x, icdf_log_logistic(np, 1, 1));
|
|
CHECK_RELERR(1/(2*x), icdf_log_logistic(np, .5, 1));
|
|
CHECK_RELERR(2/x, icdf_log_logistic(np, 2, 1));
|
|
CHECK_RELERR(1/sqrt(x), icdf_log_logistic(np, 1, 2));
|
|
CHECK_RELERR(1/(2*sqrt(x)),
|
|
icdf_log_logistic(np, .5, 2));
|
|
CHECK_RELERR(2/sqrt(x), icdf_log_logistic(np, 2, 2));
|
|
CHECK_RELERR(1/(x*x), icdf_log_logistic(np, 1, .5));
|
|
CHECK_RELERR(1/(2*x*x), icdf_log_logistic(np, .5, .5));
|
|
CHECK_RELERR(2/(x*x), icdf_log_logistic(np, 2, .5));
|
|
}
|
|
|
|
CHECK_RELERR(1/x, isf_log_logistic(p, 1, 1));
|
|
CHECK_RELERR(1/(2*x), isf_log_logistic(p, .5, 1));
|
|
CHECK_RELERR(2/x, isf_log_logistic(p, 2, 1));
|
|
CHECK_RELERR(1/sqrt(x), isf_log_logistic(p, 1, 2));
|
|
CHECK_RELERR(1/(2*sqrt(x)), isf_log_logistic(p, .5, 2));
|
|
CHECK_RELERR(2/sqrt(x), isf_log_logistic(p, 2, 2));
|
|
CHECK_RELERR(1/(x*x), isf_log_logistic(p, 1, .5));
|
|
CHECK_RELERR(1/(2*x*x), isf_log_logistic(p, .5, .5));
|
|
CHECK_RELERR(2/(x*x), isf_log_logistic(p, 2, .5));
|
|
}
|
|
|
|
for (i = 0; i <= 100; i++) {
|
|
double p0 = (double)i/100;
|
|
|
|
CHECK_RELERR(0.5*p0/(1 - 0.5*p0), sample_log_logistic(0, p0));
|
|
CHECK_RELERR((1 - 0.5*p0)/(0.5*p0),
|
|
sample_log_logistic(1, p0));
|
|
}
|
|
|
|
if (!ok)
|
|
printf("fail log logistic cdf/sf\n");
|
|
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
;
|
|
}
|
|
|
|
/**
|
|
* Test the cdf, sf, icdf, isf of the Weibull distribution.
|
|
*/
|
|
static void
|
|
test_weibull(void *arg)
|
|
{
|
|
(void) arg;
|
|
|
|
static const struct {
|
|
/* x is a point in the support of the Weibull distribution */
|
|
double x;
|
|
/* 'p' is the probability that a random variable X for a given Weibull
|
|
* probability ditribution will take value less-or-equal to x */
|
|
double p;
|
|
/* 'np' is the probability that a random variable X for a given Weibull
|
|
* probability distribution will take value greater-or-equal to x. */
|
|
double np;
|
|
} cases[] = {
|
|
{ 0, 0, 1 },
|
|
{ 1e-300, 1e-300, 1 },
|
|
{ 1e-17, 1e-17, 1 },
|
|
{ .1, .09516258196404043, .9048374180359595 },
|
|
{ .5, .3934693402873666, .6065306597126334 },
|
|
{ .6931471805599453, .5, .5 },
|
|
{ 1, .6321205588285577, .36787944117144233 },
|
|
{ 10, .9999546000702375, 4.5399929762484854e-5 },
|
|
{ 36, .9999999999999998, 2.319522830243569e-16 },
|
|
{ 37, .9999999999999999, 8.533047625744066e-17 },
|
|
{ 38, 1, 3.1391327920480296e-17 },
|
|
{ 100, 1, 3.720075976020836e-44 },
|
|
{ 708, 1, 3.307553003638408e-308 },
|
|
{ 710, 1, 4.47628622567513e-309 },
|
|
{ 1000, 1, 0 },
|
|
{ HUGE_VAL, 1, 0 },
|
|
};
|
|
double relerr_bound = 3e-15;
|
|
size_t i;
|
|
bool ok = true;
|
|
|
|
for (i = 0; i < arraycount(cases); i++) {
|
|
double x = cases[i].x;
|
|
double p = cases[i].p;
|
|
double np = cases[i].np;
|
|
|
|
CHECK_RELERR(p, cdf_weibull(x, 1, 1));
|
|
CHECK_RELERR(p, cdf_weibull(x/2, .5, 1));
|
|
CHECK_RELERR(p, cdf_weibull(x*2, 2, 1));
|
|
/* For 0 < x < sqrt(DBL_MIN), x^2 loses lots of bits. */
|
|
if (x <= 0 ||
|
|
sqrt(DBL_MIN) <= x) {
|
|
CHECK_RELERR(p, cdf_weibull(x*x, 1, .5));
|
|
CHECK_RELERR(p, cdf_weibull(x*x/2, .5, .5));
|
|
CHECK_RELERR(p, cdf_weibull(x*x*2, 2, .5));
|
|
}
|
|
CHECK_RELERR(p, cdf_weibull(sqrt(x), 1, 2));
|
|
CHECK_RELERR(p, cdf_weibull(sqrt(x)/2, .5, 2));
|
|
CHECK_RELERR(p, cdf_weibull(sqrt(x)*2, 2, 2));
|
|
CHECK_RELERR(np, sf_weibull(x, 1, 1));
|
|
CHECK_RELERR(np, sf_weibull(x/2, .5, 1));
|
|
CHECK_RELERR(np, sf_weibull(x*2, 2, 1));
|
|
CHECK_RELERR(np, sf_weibull(x*x, 1, .5));
|
|
CHECK_RELERR(np, sf_weibull(x*x/2, .5, .5));
|
|
CHECK_RELERR(np, sf_weibull(x*x*2, 2, .5));
|
|
if (x >= 10) {
|
|
/*
|
|
* exp amplifies the error of sqrt(x)^2
|
|
* proportionally to exp(x); for large inputs
|
|
* this is significant.
|
|
*/
|
|
double t = -expm1(-x*(2*DBL_EPSILON + DBL_EPSILON));
|
|
relerr_bound = t + DBL_EPSILON + t*DBL_EPSILON;
|
|
if (relerr_bound < 3e-15)
|
|
/*
|
|
* The tests are written only to 16
|
|
* decimal places anyway even if your
|
|
* `double' is, say, i387 binary80, for
|
|
* whatever reason.
|
|
*/
|
|
relerr_bound = 3e-15;
|
|
CHECK_RELERR(np, sf_weibull(sqrt(x), 1, 2));
|
|
CHECK_RELERR(np, sf_weibull(sqrt(x)/2, .5, 2));
|
|
CHECK_RELERR(np, sf_weibull(sqrt(x)*2, 2, 2));
|
|
}
|
|
|
|
if (p <= 0.75) {
|
|
/*
|
|
* For p near 1, not enough precision near 1 to
|
|
* recover x.
|
|
*/
|
|
CHECK_RELERR(x, icdf_weibull(p, 1, 1));
|
|
CHECK_RELERR(x/2, icdf_weibull(p, .5, 1));
|
|
CHECK_RELERR(x*2, icdf_weibull(p, 2, 1));
|
|
}
|
|
if (p >= 0.25 && !tor_isinf(x) && np > 0) {
|
|
/*
|
|
* For p near 0, not enough precision in np
|
|
* near 1 to recover x. For 0, isf gives inf,
|
|
* even if p is precise enough for the icdf to
|
|
* work.
|
|
*/
|
|
CHECK_RELERR(x, isf_weibull(np, 1, 1));
|
|
CHECK_RELERR(x/2, isf_weibull(np, .5, 1));
|
|
CHECK_RELERR(x*2, isf_weibull(np, 2, 1));
|
|
}
|
|
}
|
|
|
|
for (i = 0; i <= 100; i++) {
|
|
double p0 = (double)i/100;
|
|
|
|
CHECK_RELERR(3*sqrt(-log(p0/2)), sample_weibull(0, p0, 3, 2));
|
|
CHECK_RELERR(3*sqrt(-log1p(-p0/2)),
|
|
sample_weibull(1, p0, 3, 2));
|
|
}
|
|
|
|
if (!ok)
|
|
printf("fail Weibull cdf/sf\n");
|
|
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
;
|
|
}
|
|
|
|
/**
|
|
* Test the cdf, sf, icdf, and isf of the generalized Pareto
|
|
* distribution.
|
|
*/
|
|
static void
|
|
test_genpareto(void *arg)
|
|
{
|
|
(void) arg;
|
|
|
|
struct {
|
|
/* xi is the 'xi' parameter of the generalized Pareto distribution, and the
|
|
* rest are the same as in the above tests */
|
|
double xi, x, p, np;
|
|
} cases[] = {
|
|
{ 0, 0, 0, 1 },
|
|
{ 1e-300, .004, 3.992010656008528e-3, .9960079893439915 },
|
|
{ 1e-300, .1, .09516258196404043, .9048374180359595 },
|
|
{ 1e-300, 1, .6321205588285577, .36787944117144233 },
|
|
{ 1e-300, 10, .9999546000702375, 4.5399929762484854e-5 },
|
|
{ 1e-200, 1e-16, 9.999999999999999e-17, .9999999999999999 },
|
|
{ 1e-16, 1e-200, 9.999999999999998e-201, 1 },
|
|
{ 1e-16, 1e-16, 1e-16, 1 },
|
|
{ 1e-16, .004, 3.992010656008528e-3, .9960079893439915 },
|
|
{ 1e-16, .1, .09516258196404043, .9048374180359595 },
|
|
{ 1e-16, 1, .6321205588285577, .36787944117144233 },
|
|
{ 1e-16, 10, .9999546000702375, 4.539992976248509e-5 },
|
|
{ 1e-10, 1e-6, 9.999995000001667e-7, .9999990000005 },
|
|
{ 1e-8, 1e-8, 9.999999950000001e-9, .9999999900000001 },
|
|
{ 1, 1e-300, 1e-300, 1 },
|
|
{ 1, 1e-16, 1e-16, .9999999999999999 },
|
|
{ 1, .1, .09090909090909091, .9090909090909091 },
|
|
{ 1, 1, .5, .5 },
|
|
{ 1, 10, .9090909090909091, .0909090909090909 },
|
|
{ 1, 100, .9900990099009901, .0099009900990099 },
|
|
{ 1, 1000, .999000999000999, 9.990009990009992e-4 },
|
|
{ 10, 1e-300, 1e-300, 1 },
|
|
{ 10, 1e-16, 9.999999999999995e-17, .9999999999999999 },
|
|
{ 10, .1, .06696700846319258, .9330329915368074 },
|
|
{ 10, 1, .21320655780322778, .7867934421967723 },
|
|
{ 10, 10, .3696701667040189, .6303298332959811 },
|
|
{ 10, 100, .49886285755007337, .5011371424499267 },
|
|
{ 10, 1000, .6018968102992647, .3981031897007353 },
|
|
};
|
|
double xi_array[] = { -1.5, -1, -1e-30, 0, 1e-30, 1, 1.5 };
|
|
size_t i, j;
|
|
double relerr_bound = 3e-15;
|
|
bool ok = true;
|
|
|
|
for (i = 0; i < arraycount(cases); i++) {
|
|
double xi = cases[i].xi;
|
|
double x = cases[i].x;
|
|
double p = cases[i].p;
|
|
double np = cases[i].np;
|
|
|
|
CHECK_RELERR(p, cdf_genpareto(x, 0, 1, xi));
|
|
CHECK_RELERR(p, cdf_genpareto(x*2, 0, 2, xi));
|
|
CHECK_RELERR(p, cdf_genpareto(x/2, 0, .5, xi));
|
|
CHECK_RELERR(np, sf_genpareto(x, 0, 1, xi));
|
|
CHECK_RELERR(np, sf_genpareto(x*2, 0, 2, xi));
|
|
CHECK_RELERR(np, sf_genpareto(x/2, 0, .5, xi));
|
|
|
|
if (p < .5) {
|
|
CHECK_RELERR(x, icdf_genpareto(p, 0, 1, xi));
|
|
CHECK_RELERR(x*2, icdf_genpareto(p, 0, 2, xi));
|
|
CHECK_RELERR(x/2, icdf_genpareto(p, 0, .5, xi));
|
|
}
|
|
if (np < .5) {
|
|
CHECK_RELERR(x, isf_genpareto(np, 0, 1, xi));
|
|
CHECK_RELERR(x*2, isf_genpareto(np, 0, 2, xi));
|
|
CHECK_RELERR(x/2, isf_genpareto(np, 0, .5, xi));
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < arraycount(xi_array); i++) {
|
|
for (j = 0; j <= 100; j++) {
|
|
double p0 = (j == 0 ? 2*DBL_MIN : (double)j/100);
|
|
|
|
/* This is actually a check against 0, but we do <= so that the compiler
|
|
does not raise a -Wfloat-equal */
|
|
if (fabs(xi_array[i]) <= 0) {
|
|
/*
|
|
* When xi == 0, the generalized Pareto
|
|
* distribution reduces to an
|
|
* exponential distribution.
|
|
*/
|
|
CHECK_RELERR(-log(p0/2),
|
|
sample_genpareto(0, p0, 0));
|
|
CHECK_RELERR(-log1p(-p0/2),
|
|
sample_genpareto(1, p0, 0));
|
|
} else {
|
|
CHECK_RELERR(expm1(-xi_array[i]*log(p0/2))/xi_array[i],
|
|
sample_genpareto(0, p0, xi_array[i]));
|
|
CHECK_RELERR((j == 0 ? DBL_MIN :
|
|
expm1(-xi_array[i]*log1p(-p0/2))/xi_array[i]),
|
|
sample_genpareto(1, p0, xi_array[i]));
|
|
}
|
|
|
|
CHECK_RELERR(isf_genpareto(p0/2, 0, 1, xi_array[i]),
|
|
sample_genpareto(0, p0, xi_array[i]));
|
|
CHECK_RELERR(icdf_genpareto(p0/2, 0, 1, xi_array[i]),
|
|
sample_genpareto(1, p0, xi_array[i]));
|
|
}
|
|
}
|
|
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
;
|
|
}
|
|
|
|
/**
|
|
* Test the deterministic sampler for uniform distribution on [a, b].
|
|
*
|
|
* This currently only tests whether the outcome lies within [a, b].
|
|
*/
|
|
static void
|
|
test_uniform_interval(void *arg)
|
|
{
|
|
(void) arg;
|
|
struct {
|
|
/* Sample from a uniform distribution with parameters 'a' and 'b', using
|
|
* 't' as the sampling index. */
|
|
double t, a, b;
|
|
} cases[] = {
|
|
{ 0, 0, 0 },
|
|
{ 0, 0, 1 },
|
|
{ 0, 1.0000000000000007, 3.999999999999995 },
|
|
{ 0, 4000, 4000 },
|
|
{ 0.42475836677491291, 4000, 4000 },
|
|
{ 0, -DBL_MAX, DBL_MAX },
|
|
{ 0.25, -DBL_MAX, DBL_MAX },
|
|
{ 0.5, -DBL_MAX, DBL_MAX },
|
|
};
|
|
size_t i = 0;
|
|
bool ok = true;
|
|
|
|
for (i = 0; i < arraycount(cases); i++) {
|
|
double t = cases[i].t;
|
|
double a = cases[i].a;
|
|
double b = cases[i].b;
|
|
|
|
CHECK_LE(a, sample_uniform_interval(t, a, b));
|
|
CHECK_LE(sample_uniform_interval(t, a, b), b);
|
|
|
|
CHECK_LE(a, sample_uniform_interval(1 - t, a, b));
|
|
CHECK_LE(sample_uniform_interval(1 - t, a, b), b);
|
|
|
|
CHECK_LE(sample_uniform_interval(t, -b, -a), -a);
|
|
CHECK_LE(-b, sample_uniform_interval(t, -b, -a));
|
|
|
|
CHECK_LE(sample_uniform_interval(1 - t, -b, -a), -a);
|
|
CHECK_LE(-b, sample_uniform_interval(1 - t, -b, -a));
|
|
}
|
|
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
;
|
|
}
|
|
|
|
/********************** Stochastic tests ****************************/
|
|
|
|
/*
|
|
* Psi test, sometimes also called G-test. The psi test statistic,
|
|
* suitably scaled, has chi^2 distribution, but the psi test tends to
|
|
* have better statistical power in practice to detect deviations than
|
|
* the chi^2 test does. (The chi^2 test statistic is the first term of
|
|
* the Taylor expansion of the psi test statistic.) The psi test is
|
|
* generic, for any CDF; particular distributions might have higher-
|
|
* power tests to distinguish them from predictable deviations or bugs.
|
|
*
|
|
* We choose the psi critical value so that a single psi test has
|
|
* probability below alpha = 1% of spuriously failing even if all the
|
|
* code is correct. But the false positive rate for a suite of n tests
|
|
* is higher: 1 - Binom(0; n, alpha) = 1 - (1 - alpha)^n. For n = 10,
|
|
* this is about 10%, and for n = 100 it is well over 50%.
|
|
*
|
|
* Given that these tests will run with every CI job, we want to drive down the
|
|
* false positive rate. We can drive it down by running each test four times,
|
|
* and accepting it if it passes at least once; in that case, it is as if we
|
|
* used Binom(4; 2, alpha) = alpha^4 as the false positive rate for each test,
|
|
* and for n = 10 tests, it would be 9.99999959506e-08. If each CI build has 14
|
|
* jobs, then the chance of a CI build failing is 1.39999903326e-06, which
|
|
* means that a CI build will break with probability 50% after about 495106
|
|
* builds.
|
|
*
|
|
* The critical value for a chi^2 distribution with 100 degrees of
|
|
* freedom and false positive rate alpha = 1% was taken from:
|
|
*
|
|
* NIST/SEMATECH e-Handbook of Statistical Methods, Section
|
|
* 1.3.6.7.4 `Critical Values of the Chi-Square Distribution',
|
|
* <http://www.itl.nist.gov/div898/handbook/eda/section3/eda3674.htm>,
|
|
* retrieved 2018-10-28.
|
|
*/
|
|
|
|
static const size_t NSAMPLES = 100000;
|
|
/* Number of chances we give to the test to succeed. */
|
|
static const unsigned NTRIALS = 4;
|
|
/* Number of times we want the test to pass per NTRIALS. */
|
|
static const unsigned NPASSES_MIN = 1;
|
|
|
|
#define PSI_DF 100 /* degrees of freedom */
|
|
static const double PSI_CRITICAL = 135.807; /* critical value, alpha = .01 */
|
|
|
|
/**
|
|
* Perform a psi test on an array of sample counts, C, adding up to N
|
|
* samples, and an array of log expected probabilities, logP,
|
|
* representing the null hypothesis for the distribution of samples
|
|
* counted. Return false if the psi test rejects the null hypothesis,
|
|
* true if otherwise.
|
|
*/
|
|
static bool
|
|
psi_test(const size_t C[PSI_DF], const double logP[PSI_DF], size_t N)
|
|
{
|
|
double psi = 0;
|
|
double c = 0; /* Kahan compensation */
|
|
double t, u;
|
|
size_t i;
|
|
|
|
for (i = 0; i < PSI_DF; i++) {
|
|
/*
|
|
* c*log(c/(n*p)) = (1/n) * f*log(f/p) where f = c/n is
|
|
* the frequency, and f*log(f/p) ---> 0 as f ---> 0, so
|
|
* this is a reasonable choice. Further, any mass that
|
|
* _fails_ to turn up in this bin will inflate another
|
|
* bin instead, so we don't really lose anything by
|
|
* ignoring empty bins even if they have high
|
|
* probability.
|
|
*/
|
|
if (C[i] == 0)
|
|
continue;
|
|
t = C[i]*(log((double)C[i]/N) - logP[i]) - c;
|
|
u = psi + t;
|
|
c = (u - psi) - t;
|
|
psi = u;
|
|
}
|
|
psi *= 2;
|
|
|
|
return psi <= PSI_CRITICAL;
|
|
}
|
|
|
|
static bool
|
|
test_stochastic_geometric_impl(double p)
|
|
{
|
|
const struct geometric_t geometric = {
|
|
.base = GEOMETRIC(geometric),
|
|
.p = p,
|
|
};
|
|
double logP[PSI_DF] = {0};
|
|
unsigned ntry = NTRIALS, npass = 0;
|
|
unsigned i;
|
|
size_t j;
|
|
|
|
/* Compute logP[i] = Geom(i + 1; p). */
|
|
for (i = 0; i < PSI_DF - 1; i++)
|
|
logP[i] = logpmf_geometric(i + 1, p);
|
|
|
|
/* Compute logP[n-1] = log (1 - (P[0] + P[1] + ... + P[n-2])). */
|
|
logP[PSI_DF - 1] = log1mexp(logsumexp(logP, PSI_DF - 1));
|
|
|
|
while (ntry --> 0) {
|
|
size_t C[PSI_DF] = {0};
|
|
|
|
for (j = 0; j < NSAMPLES; j++) {
|
|
double n_tmp = dist_sample(&geometric.base);
|
|
|
|
/* Must be an integer. (XXX -Wfloat-equal) */
|
|
tor_assert(ceil(n_tmp) <= n_tmp && ceil(n_tmp) >= n_tmp);
|
|
|
|
/* Must be a positive integer. */
|
|
tor_assert(n_tmp >= 1);
|
|
|
|
/* Probability of getting a value in the billions is negligible. */
|
|
tor_assert(n_tmp <= (double)UINT_MAX);
|
|
|
|
unsigned n = (unsigned) n_tmp;
|
|
|
|
if (n > PSI_DF)
|
|
n = PSI_DF;
|
|
C[n - 1]++;
|
|
}
|
|
|
|
if (psi_test(C, logP, NSAMPLES)) {
|
|
if (++npass >= NPASSES_MIN)
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (npass >= NPASSES_MIN) {
|
|
/* printf("pass %s sampler\n", "geometric"); */
|
|
return true;
|
|
} else {
|
|
printf("fail %s sampler\n", "geometric");
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Divide the support of <b>dist</b> into histogram bins in <b>logP</b>. Start
|
|
* at the 1st percentile and ending at the 99th percentile. Pick the bin
|
|
* boundaries using linear interpolation so that they are uniformly spaced.
|
|
*
|
|
* In each bin logP[i] we insert the expected log-probability that a sampled
|
|
* value will fall into that bin. We will use this as the null hypothesis of
|
|
* the psi test.
|
|
*
|
|
* Set logP[i] = log(CDF(x_i) - CDF(x_{i-1})), where x_-1 = -inf, x_n =
|
|
* +inf, and x_i = i*(hi - lo)/(n - 2).
|
|
*/
|
|
static void
|
|
bin_cdfs(const struct dist_t *dist, double lo, double hi, double *logP,
|
|
size_t n)
|
|
{
|
|
#define CDF(x) dist_cdf(dist, x)
|
|
#define SF(x) dist_sf(dist, x)
|
|
const double w = (hi - lo)/(n - 2);
|
|
double halfway = dist_icdf(dist, 0.5);
|
|
double x_0, x_1;
|
|
size_t i;
|
|
size_t n2 = ceil_to_size_t((halfway - lo)/w);
|
|
|
|
tor_assert(lo <= halfway);
|
|
tor_assert(halfway <= hi);
|
|
tor_assert(n2 <= n);
|
|
|
|
x_1 = lo;
|
|
logP[0] = log(CDF(x_1) - 0); /* 0 = CDF(-inf) */
|
|
for (i = 1; i < n2; i++) {
|
|
x_0 = x_1;
|
|
/* do the linear interpolation */
|
|
x_1 = (i <= n/2 ? lo + i*w : hi - (n - 2 - i)*w);
|
|
/* set the expected log-probability */
|
|
logP[i] = log(CDF(x_1) - CDF(x_0));
|
|
}
|
|
x_0 = hi;
|
|
logP[n - 1] = log(SF(x_0) - 0); /* 0 = SF(+inf) = 1 - CDF(+inf) */
|
|
|
|
/* In this loop we are filling out the high part of the array. We are using
|
|
* SF because in these cases the CDF is near 1 where precision is lower. So
|
|
* instead we are using SF near 0 where the precision is higher. We have
|
|
* SF(t) = 1 - CDF(t). */
|
|
for (i = 1; i < n - n2; i++) {
|
|
x_1 = x_0;
|
|
/* do the linear interpolation */
|
|
x_0 = (i <= n/2 ? hi - i*w : lo + (n - 2 - i)*w);
|
|
/* set the expected log-probability */
|
|
logP[n - i - 1] = log(SF(x_0) - SF(x_1));
|
|
}
|
|
#undef SF
|
|
#undef CDF
|
|
}
|
|
|
|
/**
|
|
* Draw NSAMPLES samples from dist, counting the number of samples x in
|
|
* the ith bin C[i] if x_{i-1} <= x < x_i, where x_-1 = -inf, x_n =
|
|
* +inf, and x_i = i*(hi - lo)/(n - 2).
|
|
*/
|
|
static void
|
|
bin_samples(const struct dist_t *dist, double lo, double hi, size_t *C,
|
|
size_t n)
|
|
{
|
|
const double w = (hi - lo)/(n - 2);
|
|
size_t i;
|
|
|
|
for (i = 0; i < NSAMPLES; i++) {
|
|
double x = dist_sample(dist);
|
|
size_t bin;
|
|
|
|
if (x < lo)
|
|
bin = 0;
|
|
else if (x < hi)
|
|
bin = 1 + floor_to_size_t((x - lo)/w);
|
|
else
|
|
bin = n - 1;
|
|
tor_assert(bin < n);
|
|
C[bin]++;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Carry out a Psi test on <b>dist</b>.
|
|
*
|
|
* Sample NSAMPLES from dist, putting them in bins from -inf to lo to
|
|
* hi to +inf, and apply up to two psi tests. True if at least one psi
|
|
* test passes; false if not. False positive rate should be bounded by
|
|
* 0.01^2 = 0.0001.
|
|
*/
|
|
static bool
|
|
test_psi_dist_sample(const struct dist_t *dist)
|
|
{
|
|
double logP[PSI_DF] = {0};
|
|
unsigned ntry = NTRIALS, npass = 0;
|
|
double lo = dist_icdf(dist, 1/(double)(PSI_DF + 2));
|
|
double hi = dist_isf(dist, 1/(double)(PSI_DF + 2));
|
|
|
|
/* Create the null hypothesis in logP */
|
|
bin_cdfs(dist, lo, hi, logP, PSI_DF);
|
|
|
|
/* Now run the test */
|
|
while (ntry --> 0) {
|
|
size_t C[PSI_DF] = {0};
|
|
bin_samples(dist, lo, hi, C, PSI_DF);
|
|
if (psi_test(C, logP, NSAMPLES)) {
|
|
if (++npass >= NPASSES_MIN)
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Did we fail or succeed? */
|
|
if (npass >= NPASSES_MIN) {
|
|
/* printf("pass %s sampler\n", dist_name(dist));*/
|
|
return true;
|
|
} else {
|
|
printf("fail %s sampler\n", dist_name(dist));
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static void
|
|
write_stochastic_warning(void)
|
|
{
|
|
if (tinytest_cur_test_has_failed()) {
|
|
printf("\n"
|
|
"NOTE: This is a stochastic test, and we expect it to fail from\n"
|
|
"time to time, with some low probability. If you see it fail more\n"
|
|
"than one trial in 100, though, please tell us.\n\n");
|
|
}
|
|
}
|
|
|
|
static void
|
|
test_stochastic_uniform(void *arg)
|
|
{
|
|
(void) arg;
|
|
|
|
const struct uniform_t uniform01 = {
|
|
.base = UNIFORM(uniform01),
|
|
.a = 0,
|
|
.b = 1,
|
|
};
|
|
const struct uniform_t uniform_pos = {
|
|
.base = UNIFORM(uniform_pos),
|
|
.a = 1.23,
|
|
.b = 4.56,
|
|
};
|
|
const struct uniform_t uniform_neg = {
|
|
.base = UNIFORM(uniform_neg),
|
|
.a = -10,
|
|
.b = -1,
|
|
};
|
|
const struct uniform_t uniform_cross = {
|
|
.base = UNIFORM(uniform_cross),
|
|
.a = -1.23,
|
|
.b = 4.56,
|
|
};
|
|
const struct uniform_t uniform_subnormal = {
|
|
.base = UNIFORM(uniform_subnormal),
|
|
.a = 4e-324,
|
|
.b = 4e-310,
|
|
};
|
|
const struct uniform_t uniform_subnormal_cross = {
|
|
.base = UNIFORM(uniform_subnormal_cross),
|
|
.a = -4e-324,
|
|
.b = 4e-310,
|
|
};
|
|
bool ok = true, tests_failed = true;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok &= test_psi_dist_sample(&uniform01.base);
|
|
ok &= test_psi_dist_sample(&uniform_pos.base);
|
|
ok &= test_psi_dist_sample(&uniform_neg.base);
|
|
ok &= test_psi_dist_sample(&uniform_cross.base);
|
|
ok &= test_psi_dist_sample(&uniform_subnormal.base);
|
|
ok &= test_psi_dist_sample(&uniform_subnormal_cross.base);
|
|
|
|
tt_assert(ok);
|
|
|
|
tests_failed = false;
|
|
|
|
done:
|
|
if (tests_failed) {
|
|
write_stochastic_warning();
|
|
}
|
|
testing_disable_reproducible_rng();
|
|
}
|
|
|
|
static bool
|
|
test_stochastic_logistic_impl(double mu, double sigma)
|
|
{
|
|
const struct logistic_t dist = {
|
|
.base = LOGISTIC(dist),
|
|
.mu = mu,
|
|
.sigma = sigma,
|
|
};
|
|
|
|
/* XXX Consider some fancier logistic test. */
|
|
return test_psi_dist_sample(&dist.base);
|
|
}
|
|
|
|
static bool
|
|
test_stochastic_log_logistic_impl(double alpha, double beta)
|
|
{
|
|
const struct log_logistic_t dist = {
|
|
.base = LOG_LOGISTIC(dist),
|
|
.alpha = alpha,
|
|
.beta = beta,
|
|
};
|
|
|
|
/* XXX Consider some fancier log logistic test. */
|
|
return test_psi_dist_sample(&dist.base);
|
|
}
|
|
|
|
static bool
|
|
test_stochastic_weibull_impl(double lambda, double k)
|
|
{
|
|
const struct weibull_t dist = {
|
|
.base = WEIBULL(dist),
|
|
.lambda = lambda,
|
|
.k = k,
|
|
};
|
|
|
|
// clang-format off
|
|
/*
|
|
* XXX Consider applying a Tiku-Singh test:
|
|
*
|
|
* M.L. Tiku and M. Singh, `Testing the two-parameter
|
|
* Weibull distribution', Communications in Statistics --
|
|
* Theory and Methods A10(9), 1981, 907--918.
|
|
https://www.tandfonline.com/doi/pdf/10.1080/03610928108828082?needAccess=true
|
|
*/
|
|
// clang-format on
|
|
return test_psi_dist_sample(&dist.base);
|
|
}
|
|
|
|
static bool
|
|
test_stochastic_genpareto_impl(double mu, double sigma, double xi)
|
|
{
|
|
const struct genpareto_t dist = {
|
|
.base = GENPARETO(dist),
|
|
.mu = mu,
|
|
.sigma = sigma,
|
|
.xi = xi,
|
|
};
|
|
|
|
/* XXX Consider some fancier GPD test. */
|
|
return test_psi_dist_sample(&dist.base);
|
|
}
|
|
|
|
static void
|
|
test_stochastic_genpareto(void *arg)
|
|
{
|
|
bool ok = 0;
|
|
bool tests_failed = true;
|
|
(void) arg;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok = test_stochastic_genpareto_impl(0, 1, -0.25);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(0, 1, -1e-30);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(0, 1, 0);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(0, 1, 1e-30);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(0, 1, 0.25);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(-1, 1, -0.25);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_genpareto_impl(1, 2, 0.25);
|
|
tt_assert(ok);
|
|
|
|
tests_failed = false;
|
|
|
|
done:
|
|
if (tests_failed) {
|
|
write_stochastic_warning();
|
|
}
|
|
testing_disable_reproducible_rng();
|
|
}
|
|
|
|
static void
|
|
test_stochastic_geometric(void *arg)
|
|
{
|
|
bool ok = 0;
|
|
bool tests_failed = true;
|
|
|
|
(void) arg;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok = test_stochastic_geometric_impl(0.1);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_geometric_impl(0.5);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_geometric_impl(0.9);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_geometric_impl(1);
|
|
tt_assert(ok);
|
|
|
|
tests_failed = false;
|
|
|
|
done:
|
|
if (tests_failed) {
|
|
write_stochastic_warning();
|
|
}
|
|
testing_disable_reproducible_rng();
|
|
}
|
|
|
|
static void
|
|
test_stochastic_logistic(void *arg)
|
|
{
|
|
bool ok = 0;
|
|
bool tests_failed = true;
|
|
(void) arg;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok = test_stochastic_logistic_impl(0, 1);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_logistic_impl(0, 1e-16);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_logistic_impl(1, 10);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_logistic_impl(-10, 100);
|
|
tt_assert(ok);
|
|
|
|
tests_failed = false;
|
|
|
|
done:
|
|
if (tests_failed) {
|
|
write_stochastic_warning();
|
|
}
|
|
testing_disable_reproducible_rng();
|
|
}
|
|
|
|
static void
|
|
test_stochastic_log_logistic(void *arg)
|
|
{
|
|
bool ok = 0;
|
|
(void) arg;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok = test_stochastic_log_logistic_impl(1, 1);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_log_logistic_impl(1, 10);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_log_logistic_impl(M_E, 1e-1);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_log_logistic_impl(exp(-10), 1e-2);
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
write_stochastic_warning();
|
|
testing_disable_reproducible_rng();
|
|
}
|
|
|
|
static void
|
|
test_stochastic_weibull(void *arg)
|
|
{
|
|
bool ok = 0;
|
|
(void) arg;
|
|
|
|
testing_enable_reproducible_rng();
|
|
|
|
ok = test_stochastic_weibull_impl(1, 0.5);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_weibull_impl(1, 1);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_weibull_impl(1, 1.5);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_weibull_impl(1, 2);
|
|
tt_assert(ok);
|
|
ok = test_stochastic_weibull_impl(10, 1);
|
|
tt_assert(ok);
|
|
|
|
done:
|
|
write_stochastic_warning();
|
|
testing_disable_reproducible_rng();
|
|
UNMOCK(crypto_rand);
|
|
}
|
|
|
|
struct testcase_t prob_distr_tests[] = {
|
|
{ "logit_logistics", test_logit_logistic, TT_FORK, NULL, NULL },
|
|
{ "log_logistic", test_log_logistic, TT_FORK, NULL, NULL },
|
|
{ "weibull", test_weibull, TT_FORK, NULL, NULL },
|
|
{ "genpareto", test_genpareto, TT_FORK, NULL, NULL },
|
|
{ "uniform_interval", test_uniform_interval, TT_FORK, NULL, NULL },
|
|
END_OF_TESTCASES
|
|
};
|
|
|
|
struct testcase_t slow_stochastic_prob_distr_tests[] = {
|
|
{ "stochastic_genpareto", test_stochastic_genpareto, TT_FORK, NULL, NULL },
|
|
{ "stochastic_geometric", test_stochastic_geometric, TT_FORK, NULL, NULL },
|
|
{ "stochastic_uniform", test_stochastic_uniform, TT_FORK, NULL, NULL },
|
|
{ "stochastic_logistic", test_stochastic_logistic, TT_FORK, NULL, NULL },
|
|
{ "stochastic_log_logistic", test_stochastic_log_logistic, TT_FORK, NULL,
|
|
NULL },
|
|
{ "stochastic_weibull", test_stochastic_weibull, TT_FORK, NULL, NULL },
|
|
END_OF_TESTCASES
|
|
};
|