First Release

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@653 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 271 insertions, 0 deletions

diff --git a/exp3.c b/exp3.c
new file mode 100644
index 000000000..35ad20d26
--- /dev/null
+++ b/exp3.c
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+/* mpfr_exp -- exponential of a floating-point number
+
+Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
+
+This file is part of the MPFR Library.
+
+The MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Library General Public License as published by
+the Free Software Foundation; either version 2 of the License, or (at your
+option) any later version.
+
+The MPFR Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the MPFR Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include <stdio.h>
+#include <math.h>
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "mpfr.h"
+
+/*#define DEBUG    */
+/*#define TIMING   */
+
+int mpfr_extract(mpz_ptr , mpfr_srcptr , int );
+
+
+#define MY_INIT_MPZ(x, s) { \
+   (x)->_mp_alloc = (s); \
+   (x)->_mp_d = (mp_ptr) TMP_ALLOC((s)*BYTES_PER_MP_LIMB); \
+   (x)->_mp_size = 0; }
+
+int
+#if __STDC__
+mylog2(int x)
+#else
+mylog2(x)
+int x;
+#endif
+{
+  int i = 0;
+  for ( ; x != 1; x >>= 1, i++) ;
+  return i;
+}
+
+int
+#if __STDC__
+mpfr_exp_rational(mpfr_ptr y,mpz_srcptr p,int r,int m)
+#else
+mpfr_exp_rational(y,p,r,m)
+mpfr_ptr y;
+mpz_srcptr p;
+int r;
+int m;
+#endif
+{
+  int n,i,k,j,l;
+  mpz_t* P,*S;
+  mpz_t* ptoj;
+  int diff,expo;
+  int precy = PREC(y);
+  int * mult;
+  int prec_i_have;
+  int *nb_terms;
+  int accu;
+  n = 1 << m;
+  P = (mpz_t*) malloc((m+1) * sizeof(mpz_t));
+  S = (mpz_t*) malloc((m+1) * sizeof(mpz_t));
+
+  ptoj = (mpz_t*) malloc((m+1) * sizeof(mpz_t)); /* ptoj[i] = mantissa^(2^i) */
+  mult = (int*) malloc((m+1) * sizeof(int)); 
+  nb_terms = (int*) malloc((m+1) * sizeof(int)); 
+  mult[0] = 0;
+  for (i=0;i<=m;i++) { mpz_init(P[i]); mpz_init(S[i]); mpz_init(ptoj[i]);
+ }
+  mpz_set(ptoj[0], p);
+  for (i=1;i<m;i++) mpz_mul(ptoj[i], ptoj[i-1], ptoj[i-1]);
+  mpz_set_ui(P[0], 1);
+  mpz_set_ui(S[0], 1);
+  k = 0;
+   prec_i_have = 0; 
+   for (i=1;(prec_i_have < precy) && (i < n) ;i++) {
+    k++;
+    nb_terms[k] = 1;
+    mpz_set_ui(P[k], i+1);
+    /*    mpz_set_ui(S[k], i+1);*/
+    mpz_set(S[k], P[k]);;
+    j=i+1; l=0; while ((j & 1) == 0) {      
+      mpz_mul(S[k], S[k], ptoj[l]);
+      mpz_mul(S[k-1], S[k-1], P[k]);
+      mpz_mul_2exp(S[k-1], S[k-1], r*(1<<l));
+      mpz_add(S[k-1], S[k-1], S[k]);
+      mpz_mul(P[k-1], P[k-1], P[k]);
+      nb_terms[k-1] = nb_terms[k-1]+ nb_terms[k];
+      mult[k] = mult[k-1] + (1 << l)*(r >> 2) + mpz_sizeinbase(P[k],2) - 1;
+      prec_i_have = mult[k];
+      l++; j>>=1; k--;
+    }
+  }
+   l = 0;
+   accu = 0;
+   while (k > 0){
+     mpz_mul(S[k], S[k], ptoj[mylog2(nb_terms[k])]);
+     mpz_mul(S[k-1], S[k-1], P[k]);
+     accu += nb_terms[k];
+     mpz_mul_2exp(S[k-1], S[k-1], r* accu);
+     mpz_add(S[k-1], S[k-1], S[k]);
+     mpz_mul(P[k-1], P[k-1], P[k]);     
+     l++; k--;
+   }
+
+  diff = mpz_sizeinbase(S[0],2) - 2*precy;
+  expo = diff;
+  if (diff >=0)
+    {
+      mpz_div_2exp(S[0],S[0],diff);
+    } else 
+      {
+	mpz_mul_2exp(S[0],S[0],-diff);
+      }
+  diff = mpz_sizeinbase(P[0],2) - precy;
+  expo -= diff;
+  if (diff >=0)
+    {
+      mpz_div_2exp(P[0],P[0],diff);
+    } else
+      {
+	mpz_mul_2exp(P[0],P[0],-diff);
+	}
+  mpz_tdiv_q(S[0], S[0], P[0]);
+  mpfr_set_z(y,S[0], GMP_RNDD);
+  EXP(y) += expo;
+
+
+  mpfr_div_2exp(y, y, r*(i-1),GMP_RNDN); 
+  for (i=0;i<=m;i++) { mpz_clear(P[i]); mpz_clear(S[i]); mpz_clear(ptoj[i]); }
+  TMP_FREE(marker);
+  return 0;
+}
+
+#define shift (BITS_PER_MP_LIMB/2)
+
+int
+#if __STDC__
+mpfr_exp3(mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
+#else
+mpfr_exp3(y,x,rnd_mode)
+mpfr_ptr y;
+mpfr_srcptr x; 
+mp_rnd_t rnd_mode;
+#endif
+{
+  mpfr_t t;
+  mpfr_t x_copy;
+  int i,k;
+  mpz_t uk;
+  mpfr_t tmp;
+  int ttt;
+  int twopoweri;
+  int Prec;
+#ifdef TIMING
+  int st;
+#endif
+#ifdef TIMING
+  int dummy;
+#endif
+  int loop;
+  int prec_x;
+  int shift_x = 0;
+  int good = 0;
+  int realprec = 0;
+  int iter;
+  int logn;
+  /* commencons par 0 */
+  if (FLAG_NAN(x)) { SET_NAN(y); return 1; }
+  if (!NOTZERO(x)) { mpfr_set_ui(y, 1, GMP_RNDN); return 0; }
+
+  /* Decomposer x */
+  /* on commence par ecrire x = 1.xxxxxxxxxxxxx
+     ----- k bits -- */
+  prec_x = (int) ceil(log
+		      ((double) (PREC(x)) / (double) BITS_PER_MP_LIMB)
+		      /log(2.0));  
+  logn =  (int) ceil(log
+		      ((double) prec_x)
+		      /log(2.0));  
+  if (logn < 2) logn = 2;
+  ttt = EXP(x);
+  mpfr_init2(x_copy,PREC(x));
+  mpfr_set(x_copy,x,GMP_RNDD);
+  
+  /* on fait le shift pour que le nombre soit inferieur a 1 */
+  if (ttt > 0) 
+    {
+      shift_x = ttt;
+      mpfr_mul_2exp(x_copy,x,-ttt, GMP_RNDN); 
+      ttt = EXP(x_copy);
+    }
+  realprec = PREC(y)+logn;
+  while (!good){      
+/*    Prec = realprec+shift +shift_x + 2*prec_x;*/
+      Prec = realprec+shift+2+shift_x;
+    k = (int) ceil(log
+		   ((double) (Prec) / (double) BITS_PER_MP_LIMB)
+		   /log(2.0));
+    /* Maintenant, il faut extraire : */
+    mpfr_init2(t, Prec);
+    mpfr_init2(tmp, Prec);
+    mpfr_set_ui(tmp,1,GMP_RNDN);
+    twopoweri = BITS_PER_MP_LIMB;   
+    if (k <= prec_x) iter = k; else iter= prec_x;
+    for(i = 0; i <= iter; i++){
+      mpfr_extract(uk,x_copy,i);
+#ifdef DEBUG
+	mpz_out_str(stderr,2, uk);  
+	fprintf(stderr, "---\n");
+	fprintf(stderr, "---%d\n", twopoweri - ttt);
+#endif 
+#ifdef TIMING
+	st = cputime();
+#endif
+	if (i)
+#ifdef TIMING      
+	  for (dummy = 0; dummy < 30; dummy++)
+#endif
+	    mpfr_exp_rational(t,uk,twopoweri - ttt, k  - i + 1);
+	else
+	  {
+	    /* cas particulier : on est oblige de faire les calculs avec x/2^. 
+	       puis elever au carre (plus rapide) */    
+#ifdef TIMING
+	    for (dummy = 0; dummy < 30; dummy++)
+#endif
+	      mpfr_exp_rational(t,uk, shift + twopoweri - ttt, k+1);
+	    for (loop= 0 ; loop < shift; loop++)
+	      mpfr_mul(t,t,t,GMP_RNDD);
+	  }
+	mpfr_mul(tmp,tmp,t,GMP_RNDD); 
+#ifdef TIMING
+	fprintf(stderr, "temps : %d ms \n", cputime() - st);
+#endif
+#ifdef DEBUG
+	fprintf(stderr, "fin\n");
+	mpfr_out_str(stderr, 2, PREC(y), t, GMP_RNDD);
+	fprintf(stderr, "\n ii --- ii \n");
+#endif
+	twopoweri <<= 1;
+      }
+      for (loop= 0 ; loop < shift_x; loop++)
+	mpfr_mul(tmp,tmp,tmp,GMP_RNDD);
+      if (mpfr_can_round(tmp, realprec, GMP_RNDD, rnd_mode, PREC(y))){
+	    mpfr_set(y,tmp,rnd_mode);
+	    good = 1;
+      } else {
+	realprec += 3*logn;
+      }
+    }
+    return 0;
+} 
+
+
+
+
+
+