
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 view 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 (PLINT, input) :     Flag to indicate whether or not ``sides''
        should be draw on the figure.  If side=0 no sides are drawn,
        otherwise the sides are drawn. 
