added several tests, and a routine that generates worst cases

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1044 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 129 insertions, 3 deletions

diff --git a/tests/tcmp2.c b/tests/tcmp2.c
index b4e5e05fe..8d9866c60 100644
--- a/tests/tcmp2.c
+++ b/tests/tcmp2.c
@@ -1,6 +1,6 @@
 /* Test file for mpfr_cmp2.
 
-Copyright (C) 1999-2000 Free Software Foundation.
+Copyright (C) 1999-2001 Free Software Foundation.
 
 This file is part of the MPFR Library.
 
@@ -29,8 +29,93 @@ MA 02111-1307, USA. */
 
 void tcmp2 (double, double, int);
 void special (void);
+void worst_cases (void);
+void set_bit (mpfr_t, unsigned int, int);
 
-void tcmp2 (double x, double y, int i)
+/* set bit n of x to b, where bit 0 is the most significant one */
+void
+set_bit (mpfr_t x, unsigned int n, int b)
+{
+  unsigned l;
+  mp_size_t xn;
+
+  xn = (MPFR_PREC(x) - 1) / mp_bits_per_limb;
+  l = n / mp_bits_per_limb;
+  n %= mp_bits_per_limb;
+  n = mp_bits_per_limb - 1 - n;
+  if (b)
+    MPFR_MANT(x)[xn - l] |= (mp_limb_t) 1 << n;
+  else
+    MPFR_MANT(x)[xn - l] &= ~((mp_limb_t) 1 << n);
+}
+
+/* check that for x = 1.u 1 v 0^k low(x)
+                  y = 1.u 0 v 1^k low(y)
+   mpfr_cmp2 (x, y) returns 1 + |u| + |v| + k for low(x) >= low(y),
+                        and 1 + |u| + |v| + k + 1 otherwise */
+void
+worst_cases ()
+{
+  mpfr_t x, y;
+  unsigned int i, j, k, l, b, expected;
+
+  mpfr_init2 (x, 200);
+  mpfr_init2 (y, 200);
+  for (i=0; i<64; i++) /* |u| = i */
+    {
+      mpfr_random (x);
+      mpfr_set (y, x, GMP_RNDN);
+      set_bit (x, i + 1, 1);
+      set_bit (y, i + 1, 0);
+      for (j=0; j<64; j++) /* |v| = j */
+	{
+	  b = random () % 2;
+	  set_bit (x, i + j + 2, b);
+	  set_bit (y, i + j + 2, b);
+
+	  for (k=0; k<64; k++)
+	    {
+
+	      if (k) set_bit (x, i + j + k + 1, 0);
+	      if (k) set_bit (y, i + j + k + 1, 1);
+
+	      set_bit (x, i + j + k + 2, 1);
+	      set_bit (y, i + j + k + 2, 0);
+	      l = mpfr_cmp2 (x, y);
+	      expected = i + j + k + 1;
+	      if (l != expected)
+		{
+		  fprintf (stderr, "Error in mpfr_cmp2:\nx=");
+		  mpfr_out_str (stderr, 2, 0, x, GMP_RNDN);
+		  fprintf (stderr, "\ny=");
+		  mpfr_out_str (stderr, 2, 0, y, GMP_RNDN);
+		  fprintf (stderr, "\ngot %u instead of %u\n", l, expected);
+		  exit(1);
+		}
+
+	      set_bit (x, i + j + k + 2, 0);
+	      set_bit (x, i + j + k + 3, 0);
+	      set_bit (y, i + j + k + 3, 1);
+	      l = mpfr_cmp2 (x, y);
+	      expected = i + j + k + 2;
+	      if (l != expected)
+		{
+		  fprintf (stderr, "Error in mpfr_cmp2:\nx=");
+		  mpfr_out_str (stderr, 2, 0, x, GMP_RNDN);
+		  fprintf (stderr, "\ny=");
+		  mpfr_out_str (stderr, 2, 0, y, GMP_RNDN);
+		  fprintf (stderr, "\ngot %u instead of %u\n", l, expected);
+		  exit(1);
+		}
+	    }
+	}
+    }
+  mpfr_clear (x);
+  mpfr_clear (y);
+}
+
+void
+tcmp2 (double x, double y, int i)
 {
   mpfr_t xx, yy;
   int j;
@@ -44,7 +129,11 @@ void tcmp2 (double x, double y, int i)
   mpfr_set_d(yy, y, 0);
   j = mpfr_cmp2(xx, yy);
   if (j != i) {
-    printf("Error in mpfr_cmp2: x=%1.20e y=%1.20e mpfr_cmp2(x,y)=%d instead of %d\n",x,y,j,i); 
+    fprintf (stderr, "Error in mpfr_cmp2 for\nx=");
+    mpfr_out_str (stderr, 2, 0, xx, GMP_RNDN);
+    fprintf (stderr, "\ny=");
+    mpfr_out_str (stderr, 2, 0, yy, GMP_RNDN);
+    fprintf (stderr, "\ngot %u instead of %u\n", j, i);
     exit(1);
   }
   mpfr_clear(xx); mpfr_clear(yy);
@@ -96,6 +185,42 @@ void special ()
     exit(1);
   }
 
+  /* bug found by Nathalie Revol, 29 March 2001 */
+  mpfr_set_prec (x, 130); mpfr_set_prec (y, 130);
+  mpfr_set_str_raw (x, "0.1100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000E2");
+  mpfr_set_str_raw (y, "0.1011111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111100E2");
+  if ((j=mpfr_cmp2(x, y)) != 127) {
+    printf("Error in mpfr_cmp2:\n");
+    printf("x="); mpfr_print_raw(x); putchar('\n');
+    printf("y="); mpfr_print_raw(y); putchar('\n');
+    printf("got %d, expected 127\n", j);
+    exit(1);
+  }
+
+  /* bug found by Nathalie Revol, 2 Apr 2001 */
+  mpfr_set_prec (x, 65); mpfr_set_prec (y, 65);
+  mpfr_set_ui (x, 5, GMP_RNDN);
+  mpfr_set_str_raw (y, "0.10011111111111111111111111111111111111111111111111111111111111101E3");
+  if ((j=mpfr_cmp2(x, y)) != 63) {
+    printf("Error in mpfr_cmp2:\n");
+    printf("x="); mpfr_print_raw(x); putchar('\n');
+    printf("y="); mpfr_print_raw(y); putchar('\n');
+    printf("got %d, expected 63\n", j);
+    exit(1);
+  }
+
+  /* bug found by Nathalie Revol, 2 Apr 2001 */
+  mpfr_set_prec (x, 65); mpfr_set_prec (y, 65);
+  mpfr_set_str_raw (x, "0.10011011111000101001110000000000000000000000000000000000000000000E-69");
+  mpfr_set_str_raw (y, "0.10011011111000101001101111111111111111111111111111111111111111101E-69");
+  if ((j=mpfr_cmp2(x, y)) != 63) {
+    printf("Error in mpfr_cmp2:\n");
+    printf("x="); mpfr_print_raw(x); putchar('\n');
+    printf("y="); mpfr_print_raw(y); putchar('\n');
+    printf("got %d, expected 63\n", j);
+    exit(1);
+  }
+
   mpfr_clear(x); mpfr_clear(y);
 }
 
@@ -111,6 +236,7 @@ main (void)
     set_fpc_csr(exp.fc_word);
 #endif
 
+  worst_cases ();
   special ();
   tcmp2(5.43885304644369510000e+185, -1.87427265794105340000e-57, 1);
   tcmp2(1.06022698059744327881e+71, 1.05824655795525779205e+71, -1);