arb/fmprb/mul.c
2012-09-01 23:32:52 +02:00

119 lines
3.7 KiB
C

/*=============================================================================
This file is part of ARB.
ARB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
ARB 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2012 Fredrik Johansson
******************************************************************************/
#include "fmprb.h"
void
fmprb_mul(fmprb_t z, const fmprb_t x, const fmprb_t y, long prec)
{
long r;
if (fmprb_is_exact(x))
{
if (fmprb_is_exact(y))
{
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_set_error_result(fmprb_radref(z), fmprb_midref(z), r);
}
else
{
/* x * (y+b) = x*y + x*b */
fmpr_mul(fmprb_radref(z), fmprb_midref(x), fmprb_radref(y), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(fmprb_radref(z), fmprb_radref(z));
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), fmprb_radref(z),
fmprb_midref(z), r, FMPRB_RAD_PREC, FMPR_RND_UP);
}
}
else
{
if (fmprb_is_exact(x))
{
/* (x+a) * y = x*y + y*a */
fmpr_mul(fmprb_radref(z), fmprb_midref(y), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(fmprb_radref(z), fmprb_radref(z));
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), fmprb_radref(z),
fmprb_midref(z), r, FMPRB_RAD_PREC, FMPR_RND_UP);
}
else
{
/* (x+a)*(y+b) = x*y + x*b + y*a + a*b*/
fmpr_t t, u;
fmpr_init(t);
fmpr_init(u);
fmpr_mul(t, fmprb_midref(x), fmprb_radref(y), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(t, t);
fmpr_mul(u, fmprb_midref(y), fmprb_radref(x), FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_abs(u, u);
fmpr_add(t, t, u, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_addmul(t, fmprb_radref(x), fmprb_radref(y), FMPRB_RAD_PREC, FMPR_RND_UP);
r = fmpr_mul(fmprb_midref(z), fmprb_midref(x), fmprb_midref(y), prec, FMPR_RND_DOWN);
fmpr_add_error_result(fmprb_radref(z), t,
fmprb_midref(z), r, FMPRB_RAD_PREC, FMPR_RND_UP);
fmpr_clear(t);
fmpr_clear(u);
}
}
fmprb_adjust(z);
}
void
fmprb_mul_ui(fmprb_t z, const fmprb_t x, ulong y, long prec)
{
fmprb_t t;
fmprb_init(t);
fmprb_set_ui(t, y);
fmprb_mul(z, x, t, prec);
fmprb_clear(t);
}
void
fmprb_mul_si(fmprb_t z, const fmprb_t x, long y, long prec)
{
fmprb_t t;
fmprb_init(t);
fmprb_set_si(t, y);
fmprb_mul(z, x, t, prec);
fmprb_clear(t);
}
void
fmprb_mul_fmpz(fmprb_t z, const fmprb_t x, const fmpz_t y, long prec)
{
fmprb_t t;
fmprb_init(t);
fmprb_set_fmpz(t, y);
fmprb_mul(z, x, t, prec);
fmprb_clear(t);
}