added tests for tan(3*Pi/4) and tan(7*Pi/4)

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1742 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 37 insertions, 1 deletions

diff --git a/tests/ttan.c b/tests/ttan.c
index 9b7b4c435..b14683dd0 100644
--- a/tests/ttan.c
+++ b/tests/ttan.c
@@ -55,20 +55,56 @@ int
 main(int argc, char *argv[])
 {
   mpfr_t x;
+  unsigned int i;
+  unsigned int prec[10] = {14, 15, 19, 22, 23, 24, 25, 40, 41, 52};
+  unsigned int prec2[10] = {4, 5, 6, 19, 70, 95, 100, 106, 107, 108};
 
   check53(0.0/0.0, 0.0/0.0, GMP_RNDN); 
   check53(1.0/0.0, 0.0/0.0, GMP_RNDN); 
   check53(-1.0/0.0, 0.0/0.0, GMP_RNDN); 
 
   mpfr_init (x);
+
   mpfr_set_prec (x, 2);
   mpfr_set_d (x, 0.5, GMP_RNDN);
   mpfr_tan (x, x, GMP_RNDD);
-  if (mpfr_get_d(x) != 0.5)
+  if (mpfr_get_d (x) != 0.5)
     {
       fprintf (stderr, "mpfr_tan(0.5, GMP_RNDD) failed\n");
+      fprintf (stderr, "expected 0.5, got %f\n", mpfr_get_d (x));
       exit (1);
     }
+
+  /* check that tan(3*Pi/4) ~ -1 */
+  for (i=0; i<10; i++)
+    {
+      mpfr_set_prec (x, prec[i]);
+      mpfr_const_pi (x, GMP_RNDN);
+      mpfr_mul_ui (x, x, 3, GMP_RNDN);
+      mpfr_div_ui (x, x, 4, GMP_RNDN);
+      mpfr_tan (x, x, GMP_RNDN);
+      if (mpfr_cmp_si (x, -1))
+        {
+          fprintf (stderr, "tan(3*Pi/4) fails for prec=%u\n", prec[i]);
+          exit (1);
+        }
+    }
+
+  /* check that tan(7*Pi/4) ~ -1 */
+  for (i=0; i<10; i++)
+    {
+      mpfr_set_prec (x, prec2[i]);
+      mpfr_const_pi (x, GMP_RNDN);
+      mpfr_mul_ui (x, x, 7, GMP_RNDN);
+      mpfr_div_ui (x, x, 4, GMP_RNDN);
+      mpfr_tan (x, x, GMP_RNDN);
+      if (mpfr_cmp_si (x, -1))
+        {
+          fprintf (stderr, "tan(3*Pi/4) fails for prec=%u\n", prec2[i]);
+          exit (1);
+        }
+    }
+
   mpfr_clear (x);
 
   test_generic (2, 100, 100);