Optimize cosh a few by removing an unused intermedary var.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2897 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 74 insertions, 84 deletions

diff --git a/cosh.c b/cosh.c
index bf1caf77a..dbfd9d0b9 100644
--- a/cosh.c
+++ b/cosh.c
@@ -23,99 +23,89 @@ MA 02111-1307, USA. */
 #include "mpfr-impl.h"
 
  /* The computation of cosh is done by
-
-    cosh= 1/2[e^(x)+e^(-x)]
- */
+        cosh= 1/2[e^(x)+e^(-x)]  */
 
 int
 mpfr_cosh (mpfr_ptr y, mpfr_srcptr xt , mp_rnd_t rnd_mode)
 {
-
   /****** Declaration ******/
-    mpfr_t x;
-    mp_prec_t Nxt = MPFR_PREC(xt);
-    int inexact =0;
+  mpfr_t x;
+  mp_prec_t Nxt = MPFR_PREC(xt);
+  int inexact =0;
+  
+  if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(xt)))
+    {
+      if (MPFR_IS_NAN(xt))
+	{
+	  MPFR_SET_NAN(y);
+	  MPFR_RET_NAN;
+	}
+      else if (MPFR_IS_INF(xt))
+	{
+	  MPFR_SET_INF(y);
+	  MPFR_SET_POS(y);
+	  MPFR_RET(0);
+	}
+      else
+	{
+	  MPFR_ASSERTD(MPFR_IS_ZERO(xt));
+	  return mpfr_set_ui (y, 1, rnd_mode); /* cosh(0) = 1 */
+	}
+    }
+  
+  mpfr_init2 (x, Nxt);
+  mpfr_abs (x, xt, GMP_RNDN);
 
-    if (MPFR_UNLIKELY(MPFR_IS_SINGULAR(xt)))
+  /* General case */
+  {
+    /* Declaration of the intermediary variable */
+    mpfr_t t, te;
+    
+    /* Declaration of the size variable */
+    mp_prec_t Nx = Nxt;            /* Precision of input variable */
+    mp_prec_t Ny = MPFR_PREC(y);   /* Precision of output variable */
+    
+    mp_prec_t Nt;                  /* Precision of the intermediary variable */
+    long int err;                  /* Precision of error */
+    
+    /* compute the precision of intermediary variable */
+    Nt = MAX(Nx, Ny);
+    /* The optimal number of bits : see algorithms.ps */
+    Nt = Nt + 3 + __gmpfr_ceil_log2 (Nt);
+        
+    /* initialise of intermediary variables */
+    mpfr_init2 (t, Nt);
+    mpfr_init2 (te, Nt);
+    
+    /* First computation of cosh */
+    do
       {
-	if (MPFR_IS_NAN(xt))
-	  {
-	    MPFR_SET_NAN(y);
-	    MPFR_RET_NAN;
-	  }
-	else if (MPFR_IS_INF(xt))
-	  {
-	    MPFR_SET_INF(y);
-	    MPFR_SET_POS(y);
-	    MPFR_RET(0);
-	  }
-	else
-          {
-            MPFR_ASSERTD(MPFR_IS_ZERO(xt));
-            return mpfr_set_ui (y, 1, rnd_mode); /* cosh(0) = 1 */
-          }
+	/* Reactualisation of the precision */	
+	mpfr_set_prec (t, Nt);
+	mpfr_set_prec (te, Nt);
+	
+	/* Compute cosh */
+	mpfr_exp (te, x, GMP_RNDD);         /* exp(x) */
+	mpfr_ui_div (t, 1, te, GMP_RNDU);   /* 1/exp(x) */
+	mpfr_add (t, te, t, GMP_RNDN);      /* exp(x) + 1/exp(x)*/
+	mpfr_div_2ui (t, t, 1, GMP_RNDN);   /* 1/2(exp(x) + 1/exp(x))*/
+	
+	/* Estimation of the error */
+	err = Nt - 3;
+	
+	/* Actualisation of the precision */
+	Nt += 10;
       }
-
-    mpfr_init2 (x, Nxt);
-    mpfr_abs (x, xt, GMP_RNDN);
-
-    /* General case */
-    {
-    /* Declaration of the intermediary variable */
-      mpfr_t t, te,ti;
-
-      /* Declaration of the size variable */
-      mp_prec_t Nx = Nxt;   /* Precision of input variable */
-      mp_prec_t Ny = MPFR_PREC(y);   /* Precision of input variable */
-
-      mp_prec_t Nt;   /* Precision of the intermediary variable */
-      long int err;  /* Precision of error */
-
-      /* compute the precision of intermediary variable */
-      Nt = MAX(Nx, Ny);
-      /* the optimal number of bits : see algorithms.ps */
-      Nt = Nt + 3 + __gmpfr_ceil_log2 (Nt);
-
-
-      /* initialise of intermediary	variable */
-      mpfr_init (t);
-      mpfr_init (te);
-      mpfr_init (ti);
-
-      /* First computation of cosh */
-      do
-        {
-
-          /* reactualisation of the precision */
-
-          mpfr_set_prec (t, Nt);
-          mpfr_set_prec (te, Nt);
-          mpfr_set_prec (ti, Nt);
-
-          /* compute cosh */
-          mpfr_exp (te, x, GMP_RNDD);         /* exp(x) */
-          mpfr_ui_div (ti, 1, te, GMP_RNDU);   /* 1/exp(x) */
-          mpfr_add (t, te, ti, GMP_RNDN);      /* exp(x) + 1/exp(x)*/
-          mpfr_div_2ui (t, t, 1, GMP_RNDN);    /* 1/2(exp(x) + 1/exp(x))*/
-
-          /* estimation of the error */
-          err = Nt - 3;
-
-          /* actualisation of the precision */
-          Nt += 10;
-
-        }
-      while ((err < 0) || !mpfr_can_round (t, err, GMP_RNDN, GMP_RNDZ,
+    while ((err < 0) || !mpfr_can_round (t, err, GMP_RNDN, GMP_RNDZ,
                                            Ny + (rnd_mode == GMP_RNDN)));
 
-      inexact = mpfr_set (y, t, rnd_mode);
-
-      mpfr_clear (t);
-      mpfr_clear (ti);
-      mpfr_clear (te);
-    }
-
-    mpfr_clear (x);
+    inexact = mpfr_set (y, t, rnd_mode);
 
-    return inexact;
+    mpfr_clear (te);
+    mpfr_clear (t);
+  }
+  
+  mpfr_clear (x);
+  
+  return inexact;
 }