test file for div_ui, initial revision

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@177 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 62 insertions, 0 deletions

diff --git a/tests/tdiv_ui.c b/tests/tdiv_ui.c
new file mode 100644
index 000000000..6232ea5e8
--- /dev/null
+++ b/tests/tdiv_ui.c
@@ -0,0 +1,62 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "gmp.h"
+#include "mpfr.h"
+#include "time.h"
+
+double drand()
+{
+  double d; long int *i;
+
+  i = (long int*) &d;
+  i[0] = lrand48();
+  i[1] = lrand48();
+  if (lrand48()%2) d=-d; /* generates negative numbers */
+  return d;
+}
+
+/* returns the number of ulp's between a and b */
+int ulp(a,b) double a,b;
+{
+  double eps=1.1102230246251565404e-16; /* 2^(-53) */
+  b = (a-b)/a; if (b<0) b = -b;
+  return (int) floor(b/eps);
+}
+
+check(double d, unsigned int u, unsigned char rnd)
+{
+  mpfr_t x, y; double e, f;
+
+  mpfr_init2(x, 53); mpfr_init2(y, 53);
+  mpfr_set_machine_rnd_mode(rnd);
+  e = d / u;
+  mpfr_set_d(x, d, rnd); 
+  mpfr_div_ui(y, x, u, rnd); 
+  f = mpfr_get_d(y);
+  if (f != e && (!isnan(f) || !isnan(e))) {
+    printf("mpfr_div_ui failed for x=%1.20e, u=%lu, rnd=%d\n",d,u,rnd);
+    printf("expected result is %1.20e, got %1.20e, dif=%d ulp\n",e,f,
+	   ulp(e,f));
+    exit(1);
+  }
+  mpfr_clear(x); 
+}
+
+int
+main(int argc, char **argv)
+{
+  int i; unsigned int u; double d;
+
+  srand(getpid());
+  check(1.0, 3, 0);
+  check(1.0, 3, 1);
+  check(1.0, 3, 2);
+  check(1.0, 3, 3);
+  check(1.0, 2116118, 0);
+  for (i=0;i<1000000;i++) {
+    do { u = lrand48(); } while (u==0);
+    do { d = drand(); } while (fabs(d/u)<2.2e-307);
+    check(d, u, rand() % 4);
+  }
+}