added new function mpfr_cosu

git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14199 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 174 insertions, 0 deletions

diff --git a/tests/tcosu.c b/tests/tcosu.c
new file mode 100644
index 000000000..5fa742f76
--- /dev/null
+++ b/tests/tcosu.c
@@ -0,0 +1,174 @@
+/* Test file for mpfr_cosu.
+
+Copyright 2020 Free Software Foundation, Inc.
+Contributed by the AriC and Caramba projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MPFR Library 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
+https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
+51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#include "mpfr-test.h"
+
+static void
+test_singular (void)
+{
+  mpfr_t x, y;
+  int inexact;
+
+  mpfr_init (x);
+  mpfr_init (y);
+
+  /* check u = 0 */
+  mpfr_set_ui (x, 17, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 0, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_nan_p (y));
+
+  /* check x = NaN */
+  mpfr_set_nan (x);
+  inexact = mpfr_cosu (y, x, 1, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_nan_p (y));
+
+  /* check x = +Inf */
+  mpfr_set_inf (x, 1);
+  inexact = mpfr_cosu (y, x, 1, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_nan_p (y));
+
+  /* check x = -Inf */
+  mpfr_set_inf (x, -1);
+  inexact = mpfr_cosu (y, x, 1, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_nan_p (y));
+
+  /* check x = +0 */
+  mpfr_set_zero (x, 1);
+  inexact = mpfr_cosu (y, x, 1, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  /* check x = -0 */
+  mpfr_set_zero (x, -1);
+  inexact = mpfr_cosu (y, x, 1, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
+static void
+test_exact (void)
+{
+  mpfr_t x, y;
+  int inexact;
+
+  mpfr_init (x);
+  mpfr_init (y);
+
+  /* check 2*pi*x/u = pi/2 thus x/u = 1/4, for example x=1 and u=4 */
+  mpfr_set_ui (x, 1, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_zero_p (y) && mpfr_signbit (y) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  /* check 2*pi*x/u = pi thus x/u = 1/2, for example x=2 and u=4 */
+  mpfr_set_ui (x, 2, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_si (y, -1) == 0 && inexact == 0);
+
+  /* check 2*pi*x/u = 3*pi/2 thus x/u = 3/4, for example x=3 and u=4 */
+  mpfr_set_ui (x, 3, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_zero_p (y) && mpfr_signbit (y) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  /* check 2*pi*x/u = 2*pi thus x/u = 1, for example x=4 and u=4 */
+  mpfr_set_ui (x, 4, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0 && inexact == 0);
+
+  /* check 2*pi*x/u = -pi/2 thus x/u = -1/4, for example x=-1 and u=4 */
+  mpfr_set_si (x, -1, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_zero_p (y) && mpfr_signbit (y) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  /* check 2*pi*x/u = -pi thus x/u = -1/2, for example x=-2 and u=4 */
+  mpfr_set_si (x, -2, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_si (y, -1) == 0 && inexact == 0);
+
+  /* check 2*pi*x/u = -3*pi/2 thus x/u = -3/4, for example x=-3 and u=4 */
+  mpfr_set_si (x, -3, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_zero_p (y) && mpfr_signbit (y) == 0);
+  MPFR_ASSERTN(inexact == 0);
+
+  /* check 2*pi*x/u = -2*pi thus x/u = -1, for example x=-4 and u=4 */
+  mpfr_set_si (x, -4, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 4, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_cmp_ui (y, 1) == 0 && inexact == 0);
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
+static void
+test_regular (void)
+{
+  mpfr_t x, y, z;
+  int inexact;
+
+  mpfr_init2 (x, 53);
+  mpfr_init2 (y, 53);
+  mpfr_init2 (z, 53);
+
+  mpfr_set_ui (x, 17, MPFR_RNDN);
+  inexact = mpfr_cosu (y, x, 42, MPFR_RNDN);
+  /* y should be cos(2*17*pi/42) rounded to nearest */
+  mpfr_set_str (z, "-0xd.38462625fd3ap-4", 16, MPFR_RNDN);
+  MPFR_ASSERTN(mpfr_equal_p (y, z));
+  MPFR_ASSERTN(inexact < 0);
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+  mpfr_clear (z);
+}
+
+/* FIXME[VL]: For mpfr_cosu, the range reduction should not be expensive.
+   If I'm not mistaken, this is linear in the bitsize of the exponent
+   since one just needs to compute the argument modulo the integer u. */
+#define TEST_FUNCTION mpfr_cosu
+#define ULONG_ARG2
+#ifndef MPFR_USE_MINI_GMP
+#define REDUCE_EMAX 262143 /* otherwise arg. reduction is too expensive */
+#else
+#define REDUCE_EMAX 16383  /* reduce further since mini-gmp works in O(n^2) */
+#endif
+#include "tgeneric.c"
+
+int
+main (void)
+{
+  tests_start_mpfr ();
+
+  test_singular ();
+  test_exact ();
+  test_regular ();
+
+  test_generic (MPFR_PREC_MIN, 100, 1);
+
+  tests_end_mpfr ();
+  return 0;
+}