/*****************************************************************************
*                                                                            *
*   SIGN.SPL      Copyright (C) 2003 DSP Development Corporation             *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Returns positive, zero or negative based on sign of data    *
*                                                                            *
*   Revisions:   29 Mar 2003  RRR  Creation                                  *
*                                                                            *
*****************************************************************************/


#if @HELP_SIGN

    SIGN

    Purpose: Returns +1, 0 or -1 based on the sign of the input

    Syntax:  SIGN(x)

              x - a real or series

    Returns: A real or series

    Example:
             sign({10, 0, -10})

             returns {1, 0, -1}


    Remarks:
             If the input x is complex, SIGN returns x / mag(x).
             For example:

             sign(3 + 4i)

             return 0.6 + 0.8i

    See Also:
             Abs
             Mag
#endif



/* return +1, 0, or -1 based on sign of input */
sign(x)
{
        local s;

        if (iscomplx(x))
        {
                s = x / mag(x);
        }
        else
        {
                s = (x > 0) - (x < 0);
        }

        return(s);
}