| u, v
	  (PLFLT **, input)	   Pointers to a pair of vectored two-dimensional arrays
	   containing the x and y components of the vector data to be
	   plotted.
	   nx, ny
 	  (PLINT, input) 	    Physical dimensions of the arrays
 	    u and
 	    v.
 	  scale
	   (PLFLT, input)	     Parameter to control the scaling factor of the vectors for plotting.
	     If scale = 0 then
	     the scaling factor is automatically calculated for the data.
	     If scale < 0 then
	     the scaling factor is automatically calculated for the data and
	     then multiplied by -scale.
	     If scale > 0 then
	     the scaling factor is set to scale.
	   pltr
	  (void (*) (PLFLT, PLFLT, PLFLT *, PLFLT *, PLPointer)
           , input)	    Pointer to function that defines transformation between indices
	    in array z and the
	    world coordinates (C only).  Transformation functions are
	    provided in the PLplot library:
	    pltr0for identity mapping, andpltr1andpltr2for
	    arbitrary mappings respectively defined by one- and
	    two-dimensional arrays.  In addition, user-supplied routines
	    for the transformation can be used as well.  Examples of
	    all of these approaches are given in
	    the Section called Contour Plots from C in Chapter 3.
	    The transformation function should
	    have the form given by any ofpltr0,pltr1, orpltr2.pltr_data
	  (PLPointer, input)	    Extra parameter to help
	    pass information to pltr0,pltr1,pltr2, or whatever routine
	    that is externally supplied.
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