added new function mpfr_exp2m1 for 2^x-1

git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14384 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 151 insertions, 0 deletions

diff --git a/tests/texp2m1.c b/tests/texp2m1.c
new file mode 100644
index 000000000..903954187
--- /dev/null
+++ b/tests/texp2m1.c
@@ -0,0 +1,151 @@
+/* Test file for mpfr_exp2m1.
+
+Copyright 2001-2021 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"
+
+#define TEST_FUNCTION mpfr_exp2m1
+#define TEST_RANDOM_EMIN -36
+#define TEST_RANDOM_EMAX 36
+#include "tgeneric.c"
+
+static void
+special (void)
+{
+  mpfr_t x, y;
+  int i;
+
+  mpfr_init2 (x, 2);
+  mpfr_init2 (y, 2);
+
+  mpfr_set_nan (x);
+  mpfr_exp2m1 (y, x, MPFR_RNDN);
+  if (!mpfr_nan_p (y))
+    {
+      printf ("Error for exp2m1(NaN)\n");
+      exit (1);
+    }
+
+  mpfr_set_inf (x, 1);
+  mpfr_exp2m1 (y, x, MPFR_RNDN);
+  if (!mpfr_inf_p (y) || mpfr_sgn (y) < 0)
+    {
+      printf ("Error for exp2m1(+Inf)\n");
+      exit (1);
+    }
+
+  mpfr_set_inf (x, -1);
+  mpfr_exp2m1 (y, x, MPFR_RNDN);
+  if (mpfr_cmp_si (y, -1) != 0)
+    {
+      printf ("Error for exp2m1(-Inf)\n");
+      exit (1);
+    }
+
+  mpfr_set_ui (x, 0, MPFR_RNDN);
+  mpfr_exp2m1 (y, x, MPFR_RNDN);
+  if (MPFR_NOTZERO (y) || MPFR_IS_NEG (y))
+    {
+      printf ("Error for exp2m1(+0)\n");
+      exit (1);
+    }
+
+  mpfr_neg (x, x, MPFR_RNDN);
+  mpfr_exp2m1 (y, x, MPFR_RNDN);
+  if (MPFR_NOTZERO (y) || MPFR_IS_POS (y))
+    {
+      printf ("Error for exp2m1(-0)\n");
+      exit (1);
+    }
+
+  /* Check overflow of exp2m1(x) */
+  mpfr_clear_flags ();
+  mpfr_set_str_binary (x, "1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDN);
+  MPFR_ASSERTN (MPFR_IS_INF (x) && MPFR_IS_POS (x));
+  MPFR_ASSERTN (mpfr_overflow_p ());
+  MPFR_ASSERTN (i > 0);
+
+  mpfr_clear_flags ();
+  mpfr_set_str_binary (x, "1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDU);
+  MPFR_ASSERTN (MPFR_IS_INF (x) && MPFR_IS_POS (x));
+  MPFR_ASSERTN (mpfr_overflow_p ());
+  MPFR_ASSERTN (i > 0);
+
+  mpfr_clear_flags ();
+  mpfr_set_str_binary (x, "1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDD);
+  MPFR_ASSERTN (!MPFR_IS_INF (x) && MPFR_IS_POS (x));
+  MPFR_ASSERTN (mpfr_overflow_p ());
+  MPFR_ASSERTN (i < 0);
+
+  /* Check internal underflow of exp2m1 (x) */
+  mpfr_set_prec (x, 2);
+  mpfr_clear_flags ();
+  mpfr_set_str_binary (x, "-1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDN);
+  MPFR_ASSERTN (mpfr_cmp_si (x, -1) == 0);
+  MPFR_ASSERTN (!mpfr_overflow_p () && !mpfr_underflow_p ());
+  MPFR_ASSERTN (i < 0);
+
+  mpfr_set_str_binary (x, "-1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDD);
+  MPFR_ASSERTN (mpfr_cmp_si (x, -1) == 0);
+  MPFR_ASSERTN (!mpfr_overflow_p () && !mpfr_underflow_p ());
+  MPFR_ASSERTN (i < 0);
+
+  mpfr_set_str_binary (x, "-1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDZ);
+  MPFR_ASSERTN (mpfr_cmp_str (x, "-0.11", 2, MPFR_RNDN) == 0);
+  MPFR_ASSERTN (!mpfr_overflow_p () && !mpfr_underflow_p ());
+  MPFR_ASSERTN (i > 0);
+
+  mpfr_set_str_binary (x, "-1.1E1000000000");
+  i = mpfr_exp2m1 (x, x, MPFR_RNDU);
+  MPFR_ASSERTN (mpfr_cmp_str (x, "-0.11", 2, MPFR_RNDN) == 0);
+  MPFR_ASSERTN (!mpfr_overflow_p () && !mpfr_underflow_p ());
+  MPFR_ASSERTN (i > 0);
+
+  /* hard-coded test */
+  mpfr_set_prec (x, 32);
+  mpfr_set_prec (y, 32);
+  mpfr_set_ui_2exp (x, 1686629713UL, -29, MPFR_RNDN); /* approximates Pi */
+  i = mpfr_exp2m1 (y, x, MPFR_RNDN);
+  MPFR_ASSERTN (mpfr_cmp_ui_2exp (y, 2100501491UL, -28) == 0);
+  MPFR_ASSERTN (i < 0);
+
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
+int
+main (int argc, char *argv[])
+{
+  tests_start_mpfr ();
+
+  special ();
+
+  test_generic (MPFR_PREC_MIN, 100, 100);
+
+  tests_end_mpfr ();
+  return 0;
+}