libdimension: Modularize tests.

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);
+}