
plot3d: Plot 3-d surface plot 

DESCRIPTION:

    Plots a three dimensional surface plot within the environment set up
    by plw3d.  The surface is defined by the two-dimensional array z[
    nx][
    ny], the point z[i][j] being the value of the function at (
    x[i], 
    y[j]).  Note that the points in arrays x and y do not need to be
    equally spaced, but must be stored in ascending order.  The parameter
    opt controls the way in which the surface is displayed.  For further
    details see the PLplot documentation. The only difference between
    plmesh and plot3d is that plmesh draws the botton side of the surface,
    while plot3d only draws the surface as viewed from the top. 

SYNOPSIS:

plot3d(x, y, z, nx, ny, opt, side)

ARGUMENTS:

    x (PLFLT *, input) :    Pointer to set of x coordinate values at which
    the function is evaluated. 

    y (PLFLT *, input) :    Pointer to set of y coordinate values at which
    the function is evaluated. 

    z (PLFLT **, input) :    Pointer to a vectored two-dimensional array
    with set of function values. 

    nx (PLINT, input) :    Number of x values at which function is
    evaluated. 

    ny (PLINT, input) :    Number of y values at which function is
    evaluated. 

    opt (PLINT, input) :    Determines the way in which the surface is
    represented: opt=DRAW_LINEX: Lines are drawn showing z as a
    function of x for each value of y[j]. 
        opt=DRAW_LINEY: Lines are drawn showing z as a function of y
        for each value of x[i]. 
        opt=DRAW_LINEXY: Network of lines is drawn connecting points
        at which function is defined. 


    side (PLBOOL, input) :    Flag to indicate whether or not ``sides''
    should be draw on the figure.  If side is true sides are drawn,
    otherwise no sides are drawn. 
