sin_cos.c: precision was increased by prec/2 too early

acos.c: now increment precision by p/2 after two loops
asin.c: precision was increased by prec/2 too early


git-svn-id: svn://scm.gforge.inria.fr/svn/mpc/trunk@1398 211d60ee-9f03-0410-a15a-8952a2c7a4e4

3 files changed, 8 insertions, 7 deletions

diff --git a/src/acos.c b/src/acos.c
index 6117786..b95387d 100644
--- a/src/acos.c
+++ b/src/acos.c
@@ -24,7 +24,7 @@ along with this program. If not, see http://www.gnu.org/licenses/ .
 int
 mpc_acos (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
 {
-  int inex_re, inex_im, inex;
+  int inex_re, inex_im, inex, loop = 0;
   mpfr_prec_t p_re, p_im, p;
   mpc_t z1;
   mpfr_t pi_over_2;
@@ -190,7 +190,8 @@ mpc_acos (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
   mpfr_init2 (pi_over_2, p);
   for (;;)
     {
-      p += mpc_ceil_log2 (p) + 3;
+      loop ++;
+      p += (loop <= 2) ? mpc_ceil_log2 (p) + 3 : p / 2;
 
       mpfr_set_prec (mpc_realref(z1), p);
       mpfr_set_prec (pi_over_2, p);
diff --git a/src/asin.c b/src/asin.c
index 2d18489..e796461 100644
--- a/src/asin.c
+++ b/src/asin.c
@@ -23,10 +23,10 @@ along with this program. If not, see http://www.gnu.org/licenses/ .
 int
 mpc_asin (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
 {
-  mpfr_prec_t p, p_re, p_im, incr_p = 0;
+  mpfr_prec_t p, p_re, p_im;
   mpfr_rnd_t rnd_re, rnd_im;
   mpc_t z1;
-  int inex;
+  int inex, loop = 0;
 
   /* special values */
   if (mpfr_nan_p (mpc_realref (op)) || mpfr_nan_p (mpc_imagref (op)))
@@ -148,8 +148,8 @@ mpc_asin (mpc_ptr rop, mpc_srcptr op, mpc_rnd_t rnd)
   {
     mpfr_exp_t ex, ey, err;
 
-    p += mpc_ceil_log2 (p) + 3 + incr_p; /* incr_p is zero initially */
-    incr_p = p / 2;
+    loop ++;
+    p += (loop <= 2) ? mpc_ceil_log2 (p) + 3 : p / 2;
     mpfr_set_prec (mpc_realref(z1), p);
     mpfr_set_prec (mpc_imagref(z1), p);
 
diff --git a/src/sin_cos.c b/src/sin_cos.c
index 980e413..fe44c42 100644
--- a/src/sin_cos.c
+++ b/src/sin_cos.c
@@ -317,7 +317,7 @@ mpc_sin_cos (mpc_ptr rop_sin, mpc_ptr rop_cos, mpc_srcptr op,
       do {
          loop ++;
          ok = 1;
-         prec += (loop == 1) ? mpc_ceil_log2 (prec) + 5 : prec / 2;
+         prec += (loop <= 2) ? mpc_ceil_log2 (prec) + 5 : prec / 2;
 
          mpfr_set_prec (s, prec);
          mpfr_set_prec (c, prec);