praat/external/gsl/gsl_multiroots__enorm.c

/* multiroots/enorm.c
 * 
 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
 * 
 * This program 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 3 of the License, or (at
 * your option) any later version.
 * 
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

static double enorm (const gsl_vector * f);

static double enorm (const gsl_vector * f) {
  double e2 = 0 ;
  size_t i, n = f->size ;
  for (i = 0; i < n ; i++) {
    double fi= gsl_vector_get(f, i);
    e2 += fi * fi ;
  }
  return sqrt(e2);
}