/*****************************************************************************
*                                                                            *
*   MAXVAL.SPL   Copyright (C) 1997-2001 DSP Development Corporation         *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Returns maximum of one or two input arguments               *
*                                                                            *
*   Revisions:    9 Jun 1997  RRR  Creation                                  *
*                 6 Nov 1997  RRR  accepts single input argument             *
*                18 Mar 2000  RRR  also accepts no arguments                 *
*                27 Jul 2001  RRR  use refseries for speed                   *
*                                                                            *
*****************************************************************************/

#include 

#if @HELP_MAXVAL

    MAXVAL

    Purpose: Returns the maximum of one or two input arguments

    Syntax:  MAXVAL(val1, val2)

                 val1  -  series or numeric argument
                 val2  -  series or numeric argument

    Returns: A real or series

    Example:
             Maxval(10, 20)

             returns 20

             Maxval({1, 2, 3}, {0, 4, 2})

             returns the series {1, 4, 3}

    Example:
             W1:{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
             W2: maxval(w1)

             W2 == {7, 8, 9} the maximums of each column of W1.

    Remarks:
             MAXVAL with no input arguments uses the current Window.

    See Also:
             Max
             Min
             Minval

#endif


maxval(a, b)
{
        local idx, m;

        if (argc < 2)
        {
                if (argc < 1)
                {
                        a = refseries();
                }
                
                /* single series or array */
                if (isscalar(a))
                {
                        /* just return the scalar */
                        return(a);
                }
                else if (not(isarray(a)))
                {
                        /* else cast to series */
                        a = castseries(a);
                }

                if (numcols(a) > 1)
                {
                        /* find maxs of each column and transpose into a series */
                        m = colmax(a)';
                }
                else
                {
                        m = max(a);
                }

                if (outargc > 1)
                {
                        /*
                         *  generate "unraveled" indices and re-ravel - works
                         *  for non-equal column lengths
                         */
                        
                        idx = reshape(1..length(unravel(a)), collength(a)');

                        /* sort indices based on data */
                        idx = reorder(idx, grade(a, 0));

                        /* first row contains indices of maximums */
                        idx = idx[1, ..]';

                        /* return value and index */
                        return(m, idx);
                }
                else
                {
                        return(m);
                }
        }
        
        /* return larger of two items */
        if (isstring(a)) a = castseries(a);
        if (isstring(b)) b = castseries(b);

        return(max(a, b));
}