;+
; NAME:  grideval
; PURPOSE:
;Evaluates a function, supplied as a string, for all points of a supplied
; grid in x and y.

; INPUTS:
; KEYWORDS:
; OUTPUTS:
;
; HISTORY:
; 	Began 2007-07-27 09:19:56 by Marshall Perrin 
;-


FUNCTION grideval,   fnstring,xval,yval
	result = dblarr(n_elements(xval),n_elements(yval))
	x = dblarr(n_elements(xval),n_elements(yval))
	y = dblarr(n_elements(xval),n_elements(yval))

	for xi=0,n_elements(xval)-1 do begin
		x[xi,*]=xval[xi]
	endfor

	for yi=0,n_elements(yval)-1 do begin
		y[*,yi]=yval[yi]
	endfor

;	for yi=0,n_elements(y)-1 do begin
;		x=x[xi]
;		y=y[yi]
		r=sqrt(1.0*x^2+y^2)
		theta=atan(y,x)

		fnstr2 = "result="+fnstring
		er = execute(fnstr2)
;		result[xi,yi]=tempvar
;	endfor 
;	endfor 

	return,result

end