mirror of https://github.com/macssh/macssh.git
117 lines
3.1 KiB
C
Executable File
117 lines
3.1 KiB
C
Executable File
/* mpfr_zeta -- Riemann Zeta function at a floating-point number
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Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
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This file is part of the MPFR Library.
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The MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Library General Public License as published by
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the Free Software Foundation; either version 2 of the License, or (at your
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option) any later version.
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The MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
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License for more details.
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You should have received a copy of the GNU Library General Public License
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along with the MPFR Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include <stdio.h>
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#include <math.h>
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#include "gmp.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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#include "mpfr.h"
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int
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#if __STDC__
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mpfr_zeta(mpfr_ptr result, mpfr_srcptr op, unsigned char rnd_mode)
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#else
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mpfr_zeta(result, op, rnd_mode)
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mpfr_ptr result;
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mpfr_srcptr op;
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unsigned char rnd_mode;
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#endif
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{
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mpfr_t s,s2,x,y,u,b,v,nn,z,z2;
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int i,n,succes;
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/* first version */
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if (mpfr_get_d(op) != 2.0 || rnd_mode != GMP_RNDN
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|| PREC(result) != 53) {
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fprintf(stderr, "not yet implemented\n"); exit(1);
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}
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mpfr_set_default_prec(67);
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mpfr_init(x);
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mpfr_init(y);
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mpfr_init(s);
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mpfr_init(s2);
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mpfr_init(u);
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mpfr_init(b);
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mpfr_init(v);
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mpfr_init(nn);
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mpfr_init(z);
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mpfr_init(z2);
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mpfr_set_ui(u,1,GMP_RNDN);
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mpfr_set_ui(s,0,GMP_RNDN);
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/*s=Somme des 1/i^2 (i=100...2)*/
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n=100;
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for (i=n; i>1; i--)
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{
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mpfr_set_ui(x,i*i,GMP_RNDN);
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mpfr_div(y,u,x,GMP_RNDN);
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mpfr_add(s,s,y,GMP_RNDN);
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};
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/*mpfr_print_raw(s);printf("\n");
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t=mpfr_out_str(stdout,10,0,s,GMP_RNDN);printf("\n");*/
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/*Application d'Euler-Maclaurin, jusqu'au terme 1/n^7 - n=100)*/
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mpfr_set_ui(nn,n,GMP_RNDN);
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mpfr_div(z,u,nn,GMP_RNDN);
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mpfr_set(s2,z,GMP_RNDN);
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mpfr_mul(z2,z,z,GMP_RNDN);
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mpfr_div_2exp(v,z2,1,GMP_RNDN);
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mpfr_sub(s2,s2,v,GMP_RNDN);
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mpfr_set_ui(b,6,GMP_RNDN);
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mpfr_mul(z,z,z2,GMP_RNDN);
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mpfr_div(v,z,b,GMP_RNDN);
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mpfr_add(s2,s2,v,GMP_RNDN);
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mpfr_set_si(b,-30,GMP_RNDN);
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mpfr_mul(z,z,z2,GMP_RNDN);
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mpfr_div(v,z,b,GMP_RNDN);
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mpfr_add(s2,s2,v,GMP_RNDN);
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mpfr_set_si(b,42,GMP_RNDN);
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mpfr_mul(z,z,z2,GMP_RNDN);
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mpfr_div(v,z,b,GMP_RNDN);
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mpfr_add(s2,s2,v,GMP_RNDN);
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/*mpfr_print_raw(s2);printf("\n");
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t=mpfr_out_str(stdout,10,0,s2,GMP_RNDN);printf("\n");*/
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mpfr_add(s,s,s2,GMP_RNDN);
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/*mpfr_print_raw(s);printf("\n");
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t=mpfr_out_str(stdout,10,0,s,GMP_RNDN);printf("\n");*/
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mpfr_add(s,s,u,GMP_RNDN);
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/*mpfr_print_raw(s);printf("\n");
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t=mpfr_out_str(stdout,10,0,s,GMP_RNDN);printf("\n");*/
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/*Peut-on arrondir ? La reponse est oui*/
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succes=mpfr_can_round(s,57,GMP_RNDN,GMP_RNDN,53);
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if (succes) mpfr_set(result,s,GMP_RNDN);
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else {
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fprintf(stderr, "can't round in mpfr_zeta\n"); exit(1);
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}
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mpfr_clear(x);
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mpfr_clear(y);
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mpfr_clear(s);
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mpfr_clear(s2);
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mpfr_clear(u);
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mpfr_clear(b);
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mpfr_clear(v);
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mpfr_clear(nn);
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mpfr_clear(z);
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mpfr_clear(z2);
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return 1; /* result is inexact */
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}
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