Annotation of OpenXM_contrib/gmp/mpfr/agm.c, Revision 1.1
1.1 ! maekawa 1: /* mpfr_agm -- arithmetic-geometric mean of two floating-point numbers
! 2:
! 3: Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
! 4:
! 5: This file is part of the MPFR Library.
! 6:
! 7: The MPFR Library is free software; you can redistribute it and/or modify
! 8: it under the terms of the GNU Library General Public License as published by
! 9: the Free Software Foundation; either version 2 of the License, or (at your
! 10: option) any later version.
! 11:
! 12: The MPFR Library is distributed in the hope that it will be useful, but
! 13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
! 15: License for more details.
! 16:
! 17: You should have received a copy of the GNU Library General Public License
! 18: along with the MPFR Library; see the file COPYING.LIB. If not, write to
! 19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
! 20: MA 02111-1307, USA. */
! 21:
! 22: #include <stdio.h>
! 23: #include <math.h>
! 24: #include "gmp.h"
! 25: #include "gmp-impl.h"
! 26: #include "mpfr.h"
! 27:
! 28:
! 29: /*Memory gestion */
! 30: #define MON_INIT(xp, x, p, s) xp = (mp_ptr) TMP_ALLOC(s*BYTES_PER_MP_LIMB); x -> _mp_prec = p; x -> _mp_d = xp; x -> _mp_size = s; x -> _mp_exp = 0;
! 31:
! 32:
! 33:
! 34:
! 35: void
! 36: #ifdef __STDC__
! 37: mpfr_agm(mpfr_ptr r, mpfr_srcptr op2, mpfr_srcptr op1, unsigned char rnd_mode)
! 38: #else
! 39: mpfr_agm(r, a, b, rnd_mode)
! 40: mpfr_ptr r;
! 41: mpfr_srcptr a;
! 42: mpfr_srcptr b;
! 43: unsigned char rnd_mode;
! 44: #endif
! 45: {
! 46: int s, p, q, go_on;
! 47: double uo, vo;
! 48: mp_limb_t *up, *vp, *tmpp, *tmpup, *tmpvp, *ap, *bp;
! 49: mpfr_t u, v, tmp, tmpu, tmpv, a, b;
! 50: TMP_DECL(marker1);
! 51: TMP_DECL(marker2);
! 52:
! 53:
! 54: /* If a or b is NaN, the result is NaN */
! 55: if (FLAG_NAN(op1) || FLAG_NAN(op2))
! 56: { SET_NAN(r); return; }
! 57:
! 58:
! 59: /* If a or b is negative, the result is NaN */
! 60: if ((SIGN(op1)<0)||(SIGN(op2)<0))
! 61: { SET_NAN(r); return; }
! 62:
! 63:
! 64:
! 65: /* If a or b is 0, the result is 0 */
! 66: if ((SIGN(op1)==0)||(SIGN(op2)==0))
! 67: { SET_ZERO(r);
! 68: return;
! 69: }
! 70:
! 71: /* precision of the following calculus */
! 72: q = PREC(r);
! 73: p = q + 15;
! 74:
! 75:
! 76: /* Initialisations */
! 77: go_on=1;
! 78:
! 79: TMP_MARK(marker1);
! 80: s=(p-1)/BITS_PER_MP_LIMB+1;
! 81: MON_INIT(ap, a, p, s);
! 82: MON_INIT(bp, b, p, s);
! 83: TMP_MARK(marker2);
! 84: MON_INIT(up, u, p, s);
! 85: MON_INIT(vp, v, p, s);
! 86: MON_INIT(tmpup, tmpu, p, s);
! 87: MON_INIT(tmpvp, tmpv, p, s);
! 88: MON_INIT(tmpp, tmp, p, s);
! 89:
! 90:
! 91:
! 92: /* b and a will be the 2 operands but I want b>= a */
! 93: if (mpfr_cmp(op1,op2) > 0) {
! 94: mpfr_set(b,op1,GMP_RNDN); mpfr_set(a,op2,GMP_RNDN);
! 95: }
! 96: else {
! 97: mpfr_set(b,op2,GMP_RNDN); mpfr_set(a,op1,GMP_RNDN);
! 98: }
! 99:
! 100: vo=mpfr_get_d(b);
! 101: uo=mpfr_get_d(a);
! 102:
! 103: mpfr_set(u,a,GMP_RNDN);
! 104: mpfr_set(v,b,GMP_RNDN);
! 105:
! 106:
! 107: /* Main loop */
! 108:
! 109: while (go_on) {
! 110: int err, eq, can_round;
! 111:
! 112: eq=0;
! 113:
! 114: err=ceil((3.0/2.0*log((double)p)/log(2.0)+1.0)*exp(-(double)p*log(2.0))+3.0*exp(-2.0*(double)p*uo*log(2.0)/(vo-uo)));
! 115: if(p-err-3<=q) {
! 116: p=q+err+4;
! 117: err=ceil((3.0/2.0*log((double)p)/log(2.0)+1.0)*exp(-(double)p*log(2.0))+3.0*exp(-2.0*(double)p*uo*log(2.0)/(vo-uo)));
! 118: }
! 119:
! 120: /* Calculus of un and vn */
! 121: while (eq<=p-2) {
! 122: mpfr_mul(tmp,u,v,GMP_RNDN);
! 123: mpfr_sqrt(tmpu,tmp,GMP_RNDN);
! 124: mpfr_add(tmp,u,v,GMP_RNDN);
! 125: mpfr_div_2exp(tmpv,tmp,1,GMP_RNDN);
! 126: mpfr_set(u,tmpu,GMP_RNDN);
! 127: mpfr_set(v,tmpv,GMP_RNDN);
! 128: if (mpfr_cmp(v,u)>=0)
! 129: eq=mpfr_cmp2(v,u);
! 130: else
! 131: eq=mpfr_cmp2(u,v);
! 132: }
! 133:
! 134: /* printf("avant can_round %i bits faux\n v : ",err+3);
! 135: mpfr_print_raw(v); printf("\n u : ");
! 136: mpfr_print_raw(u);printf("\n");*/
! 137:
! 138:
! 139: /* Roundability of the result */
! 140: can_round=mpfr_can_round(v,p-err-3,GMP_RNDN,rnd_mode,q);
! 141:
! 142: if (can_round)
! 143: go_on=0;
! 144:
! 145: else {
! 146: go_on=1;
! 147: p+=5;
! 148: TMP_FREE(marker2);
! 149: TMP_MARK(marker2);
! 150: s=(p-1)/BITS_PER_MP_LIMB+1;
! 151: MON_INIT(up, u, p, s);
! 152: MON_INIT(vp, v, p, s);
! 153: MON_INIT(tmpup, tmpu, p, s);
! 154: MON_INIT(tmpvp, tmpv, p, s);
! 155: MON_INIT(tmpp, tmp, p, s);
! 156: mpfr_set(u,a,GMP_RNDN);
! 157: mpfr_set(v,b,GMP_RNDN);
! 158: }
! 159: }
! 160: /* End of while */
! 161:
! 162: /* Setting of the result */
! 163:
! 164: mpfr_set(r,v,rnd_mode);
! 165:
! 166:
! 167: /* Let's clean */
! 168: TMP_FREE(marker1);
! 169:
! 170: return ;
! 171: }
! 172:
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