Annotation of OpenXM_contrib/gmp/mpfr/asinh.c, Revision 1.1
1.1 ! ohara 1: /* mpfr_asinh -- Inverse Hyperbolic Sinus of Unsigned Integer Number
! 2:
! 3: Copyright 2001, 2002 Free Software Foundation.
! 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 Lesser General Public License as published by
! 9: the Free Software Foundation; either version 2.1 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 Lesser General Public
! 15: License for more details.
! 16:
! 17: You should have received a copy of the GNU Lesser 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 "gmp.h"
! 23: #include "gmp-impl.h"
! 24: #include "mpfr.h"
! 25: #include "mpfr-impl.h"
! 26:
! 27: /* The computation of asinh is done by
! 28:
! 29: asinh= ln(x+sqrt(x^2+1))
! 30: */
! 31: int
! 32: mpfr_asinh (mpfr_ptr y, mpfr_srcptr xt, mp_rnd_t rnd_mode)
! 33: {
! 34: int inexact;
! 35: mpfr_t x;
! 36: int flag_neg=0;
! 37: mp_prec_t Nx;
! 38:
! 39: if (MPFR_IS_NAN(xt))
! 40: {
! 41: MPFR_SET_NAN(y);
! 42: MPFR_RET_NAN;
! 43: }
! 44:
! 45: MPFR_CLEAR_NAN(y);
! 46:
! 47: if (MPFR_IS_INF(xt))
! 48: {
! 49: MPFR_SET_INF(y);
! 50: MPFR_SET_SAME_SIGN(y, xt);
! 51: MPFR_RET(0);
! 52: }
! 53:
! 54: MPFR_CLEAR_INF(y);
! 55:
! 56: if (MPFR_IS_ZERO(xt))
! 57: {
! 58: MPFR_SET_ZERO(y); /* asinh(0) = 0 */
! 59: MPFR_SET_SAME_SIGN(y, xt);
! 60: MPFR_RET(0);
! 61: }
! 62:
! 63: Nx = MPFR_PREC(xt); /* Precision of input variable */
! 64: mpfr_init2(x, Nx);
! 65: mpfr_set(x, xt, GMP_RNDN);
! 66:
! 67: if (MPFR_SIGN(x) < 0)
! 68: {
! 69: MPFR_CHANGE_SIGN(x);
! 70: flag_neg=1;
! 71: }
! 72:
! 73: /* General case */
! 74: {
! 75: /* Declaration of the intermediary variable */
! 76: mpfr_t t, te,ti;
! 77:
! 78: /* Declaration of the size variable */
! 79: mp_prec_t Nx = MPFR_PREC(x); /* Precision of input variable */
! 80: mp_prec_t Ny = MPFR_PREC(y); /* Precision of input variable */
! 81:
! 82: mp_prec_t Nt; /* Precision of the intermediary variable */
! 83: long int err; /* Precision of error */
! 84:
! 85: /* compute the precision of intermediary variable */
! 86: Nt=MAX(Nx,Ny);
! 87: /* the optimal number of bits : see algorithms.ps */
! 88: Nt=Nt+4+_mpfr_ceil_log2(Nt);
! 89:
! 90: /* initialise of intermediary variable */
! 91: mpfr_init(t);
! 92: mpfr_init(te);
! 93: mpfr_init(ti);
! 94:
! 95: /* First computation of cosh */
! 96: do {
! 97:
! 98: /* reactualisation of the precision */
! 99: mpfr_set_prec(t,Nt);
! 100: mpfr_set_prec(te,Nt);
! 101: mpfr_set_prec(ti,Nt);
! 102:
! 103: /* compute asinh */
! 104: mpfr_mul(te,x,x,GMP_RNDD); /* (x^2) */
! 105: mpfr_add_ui(ti,te,1,GMP_RNDD); /* (x^2+1) */
! 106: mpfr_sqrt(t,ti,GMP_RNDN); /* sqrt(x^2+1) */
! 107: mpfr_add(t,t,x,GMP_RNDN); /* sqrt(x^2+1)+x */
! 108: mpfr_log(t,t,GMP_RNDN); /* ln(sqrt(x^2+1)+x)*/
! 109:
! 110: /* estimation of the error see- algorithms.ps*/
! 111: /*err=Nt-_mpfr_ceil_log2(1+pow(2,3-MPFR_EXP(t)));*/
! 112: err=Nt-(MAX(3-MPFR_EXP(t),0)+1);
! 113:
! 114: /* actualisation of the precision */
! 115: Nt += 10;
! 116:
! 117: } while ((err < 0) || (!mpfr_can_round(t,err,GMP_RNDN,rnd_mode,Ny) || (MPFR_IS_ZERO(t))));
! 118:
! 119: if(flag_neg)
! 120: MPFR_CHANGE_SIGN(t);
! 121:
! 122: inexact = mpfr_set(y,t,rnd_mode);
! 123:
! 124: mpfr_clear(t);
! 125: mpfr_clear(ti);
! 126: mpfr_clear(te);
! 127: }
! 128: mpfr_clear(x);
! 129: MPFR_RET(inexact);
! 130: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>