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Diffstat (limited to 'libdimension/tests/math/polynomial.c')
| -rw-r--r-- | libdimension/tests/math/polynomial.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/libdimension/tests/math/polynomial.c b/libdimension/tests/math/polynomial.c new file mode 100644 index 0000000..eaa15cf --- /dev/null +++ b/libdimension/tests/math/polynomial.c @@ -0,0 +1,222 @@ +/************************************************************************* + * Copyright (C) 2010-2014 Tavian Barnes <tavianator@tavianator.com> * + * * + * This file is part of The Dimension Test Suite. * + * * + * The Dimension Test Suite is free software; you can redistribute it * + * and/or modify it under the terms of the GNU General Public License as * + * published by the Free Software Foundation; either version 3 of the * + * License, or (at your option) any later version. * + * * + * The Dimension Test Suite is distributed in the hope that it will be * + * useful, but WITHOUT ANY WARRANTY; without even the implied warranty * + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * + * General Public License for more details. * + * * + * You should have received a copy of the GNU General Public License * + * along with this program. If not, see <http://www.gnu.org/licenses/>. * + *************************************************************************/ + +/** + * @file + * Basic tests of the polynomial root-finder. + */ + +#include "../../math/polynomial.c" +#include "tests.h" +#include <stdarg.h> + +#define DMNSN_CLOSE_ENOUGH 1.0e-6 + +static void +dmnsn_assert_roots(const double poly[], size_t degree, size_t nroots_ex, ...) +{ + double roots[degree]; + size_t nroots = dmnsn_polynomial_solve(poly, degree, roots); + ck_assert_int_eq(nroots, nroots_ex); + + va_list ap; + va_start(ap, nroots_ex); + for (size_t i = 0; i < nroots; ++i) { + double root_ex = va_arg(ap, double); + bool found = false; + for (size_t j = 0; j < nroots; ++j) { + double root = roots[j]; + if (fabs(root_ex - root) >= dmnsn_epsilon) { + continue; + } + + double evroot = dmnsn_polynomial_evaluate(poly, degree, root); + ck_assert(fabs(evroot) < DMNSN_CLOSE_ENOUGH); + + double evmin = dmnsn_polynomial_evaluate(poly, degree, root - dmnsn_epsilon); + double evmax = dmnsn_polynomial_evaluate(poly, degree, root + dmnsn_epsilon); + ck_assert(fabs(evroot) <= fabs(evmin) && fabs(evroot) <= fabs(evmax)); + + found = true; + break; + } + + if (!found) { + for (size_t j = 0; j < nroots; ++j) { + fprintf(stderr, "roots[%zu] == %.17g\n", j, roots[j]); + } + fprintf(stderr, "----\n"); + ck_abort_msg("Expected root %.17g not found", root_ex); + } + } + va_end(ap); +} + + +DMNSN_TEST(linear, no_positive_roots) +{ + // poly[] = x + 1 + static const double poly[] = { + [1] = 1.0, + [0] = 1.0, + }; + dmnsn_assert_roots(poly, 1, 0); +} + +DMNSN_TEST(linear, one_root) +{ + // poly[] = x - 1 + static const double poly[] = { + [1] = 1.0, + [0] = -1.0, + }; + dmnsn_assert_roots(poly, 1, 1, 1.0); +} + + +DMNSN_TEST(quadratic, no_roots) +{ + // poly[] = x^2 + 1 + static const double poly[] = { + [2] = 1.0, + [1] = 0.0, + [0] = 1.0, + }; + dmnsn_assert_roots(poly, 2, 0); +} + +DMNSN_TEST(quadratic, no_positive_roots) +{ + // poly[] = (x + 1)^2 + static const double poly[] = { + [2] = 1.0, + [1] = 2.0, + [0] = 1.0, + }; + dmnsn_assert_roots(poly, 2, 0); +} + +DMNSN_TEST(quadratic, one_positive_root) +{ + // poly[] = (x + 1)*(x - 1) + static const double poly[] = { + [2] = 1.0, + [1] = 0.0, + [0] = -1.0, + }; + dmnsn_assert_roots(poly, 2, 1, 1.0); +} + +DMNSN_TEST(quadratic, two_roots) +{ + // poly[] = (x - 1.2345)*(x - 2.3456) + static const double poly[] = { + [2] = 1.0, + [1] = -3.5801, + [0] = 2.8956432, + }; + dmnsn_assert_roots(poly, 2, 2, 1.2345, 2.3456); +} + + +DMNSN_TEST(cubic, no_positive_roots) +{ + // poly[] = x^3 + 1 + static const double poly[] = { + [3] = 1.0, + [2] = 0.0, + [1] = 0.0, + [0] = 1.0, + }; + dmnsn_assert_roots(poly, 3, 0); +} + +DMNSN_TEST(cubic, one_root) +{ + // poly[] = x^3 - 1 + static const double poly[] = { + [3] = 1.0, + [2] = 0.0, + [1] = 0.0, + [0] = -1.0, + }; + dmnsn_assert_roots(poly, 3, 1, 1.0); +} + +DMNSN_TEST(cubic, two_roots) +{ + // poly[] = (x - 1)*(x - 4)^2 + static const double poly[] = { + [3] = 1.0, + [2] = -9.0, + [1] = 24.0, + [0] = -16.0, + }; + dmnsn_assert_roots(poly, 3, 2, 1.0, 4.0); +} + +DMNSN_TEST(cubic, three_roots) +{ + // poly[] = (x - 1.2345)*(x - 2.3456)*(x - 100) + static const double poly[] = { + [3] = 1.0, + [2] = -103.5801, + [1] = 360.9056432, + [0] = -289.56432, + }; + dmnsn_assert_roots(poly, 3, 3, 1.2345, 2.3456, 100.0); +} + + +DMNSN_TEST(quintic, four_roots) +{ + // poly[] = 2*(x + 1)*(x - 1.2345)*(x - 2.3456)*(x - 5)*(x - 100) + static const double poly[] = { + [5] = 2.0, + [4] = -215.1602, + [3] = 1540.4520864, + [2] = -2430.5727856, + [1] = -1292.541872, + [0] = 2895.6432, + }; + dmnsn_assert_roots(poly, 5, 4, 1.2345, 2.3456, 5.0, 100.0); +} + +// repeated_root[] = (x - 1)^6 +static const double repeated_root[7] = { + [6] = 1.0, + [5] = -6.0, + [4] = 15.0, + [3] = -20.0, + [2] = 15.0, + [1] = -6.0, + [0] = 1.0, +}; + +DMNSN_TEST(stability, equal_bounds) +{ + double root = dmnsn_bisect_root(repeated_root, 6, 1.0, 1.0); + ck_assert_msg(root == 1.0, "root == %.17g", root); +} + +DMNSN_TEST(stability, equal_values_at_bounds) +{ + double root = dmnsn_bisect_root(repeated_root, 6, 0.9, 1.1); + ck_assert_msg(fabs(root - 1.0) < dmnsn_epsilon, "root == %.17g", root); +} |