+/* Test of sqrt*() function family.
+ Copyright (C) 2012 Free Software Foundation, Inc.
+
+ This program 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.
+
+ This program 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/>. */
+
+static void
+test_function (void)
+{
+ int i;
+ int j;
+ const DOUBLE TWO_MANT_DIG =
+ /* Assume MANT_DIG <= 5 * 31.
+ Use the identity
+ n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */
+ (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
+ * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
+ * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
+ * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
+ * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));
+
+ /* Randomized tests. */
+ for (i = 0; i < SIZEOF (RANDOM); i++)
+ {
+ DOUBLE x = L_(16.0) * RANDOM[i]; /* 0.0 <= x <= 16.0 */
+ DOUBLE y = SQRT (x);
+ DOUBLE z = y * y - x;
+ ASSERT (z > - L_(16.0) / TWO_MANT_DIG
+ && z < L_(16.0) / TWO_MANT_DIG);
+ }
+
+ for (i = 0; i < SIZEOF (RANDOM) / 4; i++)
+ for (j = 0; j < SIZEOF (RANDOM) / 4; j++)
+ {
+ DOUBLE x = L_(16.0) * RANDOM[i]; /* 0.0 <= x <= 16.0 */
+ DOUBLE y = L_(16.0) * RANDOM[j]; /* 0.0 <= y <= 16.0 */
+ if (x > L_(0.0) && y > L_(0.0))
+ {
+ DOUBLE z = L_(1.0) / (x * y);
+ /* Approximately x * y * z = 1. */
+ DOUBLE p = SQRT (x) * SQRT (y) * SQRT (z);
+ ASSERT (p > L_(1.0) - L_(4.0) / TWO_MANT_DIG
+ && p < L_(1.0) + L_(4.0) / TWO_MANT_DIG);
+ }
+ }
+}
+
+volatile DOUBLE x;
+DOUBLE y;