/* $Id: polevl.c,v 1.1 2003/04/15 03:20:17 cher Exp $ */

/* This file is taken from Cephes math library */

/*
  Cephes Math Library Release 2.1:  December, 1988
  Copyright 1984, 1987, 1988 by Stephen L. Moshier
  Direct inquiries to 30 Frost Street, Cambridge, MA 02140
*/

#include "cephes.h"
#include "mconf.h"
#include <math.h>

/*							polevl.c
 *							p1evl.c
 *
 *	Evaluate polynomial
 *
 *
 *
 * SYNOPSIS:
 *
 * int N;
 * double x, y, coef[N+1], polevl[];
 *
 * y = polevl( x, coef, N );
 *
 *
 *
 * DESCRIPTION:
 *
 * Evaluates polynomial of degree N:
 *
 *                     2          N
 * y  =  C  + C x + C x  +...+ C x
 *        0    1     2          N
 *
 * Coefficients are stored in reverse order:
 *
 * coef[0] = C  , ..., coef[N] = C  .
 *            N                   0
 *
 *  The function p1evl() assumes that coef[N] = 1.0 and is
 * omitted from the array.  Its calling arguments are
 * otherwise the same as polevl().
 *
 *
 * SPEED:
 *
 * In the interest of speed, there are no checks for out
 * of bounds arithmetic.  This routine is used by most of
 * the functions in the library.  Depending on available
 * equipment features, the user may wish to rewrite the
 * program in microcode or assembly language.
 *
 */

double
cephes_polevl(double x, double coef[], int N)
{
  double ans;
  int i;
  double *p;

  p = coef;
  ans = *p++;
  i = N;

  do
    ans = ans * x  +  *p++;
  while( --i );

  return( ans );
}

/*							p1evl()	*/
/*                                          N
 * Evaluate polynomial when coefficient of x  is 1.0.
 * Otherwise same as polevl.
 */

double
cephes_p1evl(double x, double coef[], int N)
{
  double ans;
  double *p;
  int i;

  p = coef;
  ans = x + *p++;
  i = N-1;

  do
    ans = ans * x  + *p++;
  while( --i );

  return( ans );
}

/*
 * Local variables:
 *  compile-command: "make -C .."
 * End:
 */