exp.c

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/*
 
  $Id: exp.c 1669 2019-06-26 17:24:57Z coelho $
 
  Copyright 1989-2016 MINES ParisTech
 
  This file is part of Linear/C3 Library.
 
  Linear/C3 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
  any later version.
 
  Linear/C3 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 Linear/C3 Library.  If not, see <http://www.gnu.org/licenses/>.
 
*/
 
 /* package arithmetique 
  */
 
/*LINTLIBRARY*/
/* no overflow is checked 
 */
 
#ifdef HAVE_CONFIG_H
    #include "config.h"
#endif
#include <stdlib.h>
#include <stdio.h>
 
#include "arithmetique.h"
#include "linear_assert.h"
 
/* int exponentiate(x,n):  raise x to the power n
 * 
 * Precondition:        n => 0
 */
Value exponentiate(Value x, int n)
{
    Value y;
 
    /* validation - n is positive 
     */
    assert(n >= 0);
    if (n == 0) return VALUE_ONE;
 
    /* FI: la complexite pourrait etre reduite de O(n) a O(log n) 
     */
    for(y=VALUE_ONE; n>0; n--)
        value_product(y,x);
 
    return y;
}