/*****************************************************************************
*                                                                            *
*   COLPROD.SPL  Copyright (C) 2000 DSP Development Corporation              *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Calculates the product of each column of a series           *
*                                                                            *
*   Revisions:   13 Apr 2000  RRR  Creation - from PROD.SPL                  *
*                                                                            *
*****************************************************************************/

#include 

#if @HELP_COLPROD

    COLPROD

    Purpose: Calculates the product of each column of an array.

    Syntax:  COLPROD(x)

              x - input array

    Returns: A series

    Example:
             a = {{1, 2, 3},
                  {4, 5, 6},
                  {7, 8, 9}}

             b = colprod(a)

             b == {{28}, {80}, {162}}


    See Also:
             Prod
             Sum

#endif


/* product of each column */
colprod(s)
{
        local r;

        if (argc < 1) error("colprod - input series required");

        /* convert to series if required */
        if (not(isarray(s)))
        {
                s = castseries(s);
        }

        /* colreduce does just what we need */
        r = colreduce(s, "*");

        return(r);
}