/* mpfr_dot -- dot product of two array of numbers

Copyright 2018 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The GNU 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

#include "mpfr-impl.h"

/* FIXME: handle intermediate overflows and underflows. */

/* res <- a[0]*b[0] + ... + a[n-1]*b[n-1] */
int
mpfr_dot (mpfr_ptr res, const mpfr_ptr *a, const mpfr_ptr *b,
          unsigned long n, mpfr_rnd_t rnd)
{
  mpfr_t *c;
  size_t i;
  int inex;
  mpfr_ptr *tab;

  if (MPFR_UNLIKELY (n == 0))
    {
      MPFR_SET_ZERO (res);
      MPFR_SET_POS (res);
      MPFR_RET (0);
    }

  c = (mpfr_t *) mpfr_allocate_func (n * sizeof (mpfr_t));
  tab = (mpfr_ptr *) mpfr_allocate_func (n * sizeof (mpfr_ptr));
  for (i = 0; i < n; i++)
    {
      mpfr_init2 (c[i], mpfr_get_prec (a[i]) + mpfr_get_prec (b[i]));
      inex = mpfr_mul (c[i], a[i], b[i], MPFR_RNDZ); /* exact except... */
      MPFR_ASSERTN (inex == 0); /* failure in case of overflow/underflow */
      tab[i] = c[i];
    }
  inex = mpfr_sum (res, tab, n, rnd);
  for (i = 0; i < n; i++)
    mpfr_clear (c[i]);
  mpfr_free_func (c, n * sizeof (mpfr_t));
  mpfr_free_func (tab, n * sizeof (mpfr_ptr));
  return inex;
}