rect_ap - filters the field through rectangle aperture.
rect_ap filters the field (first argument) through a square or rectangular aperture. The argument sx defines the side length of the (square) aperture, the sy is the length of the second side of a rectangle, x_shift and y_shift are shifts in x and y directions and the last argument is the rotation of the aperture. Only the first argument is obligatory (centered square aperture).
F1=begin(0.01,1e-6); F2=rect_ap(F1,0.004,0.004,-0.0015,-0.002); field_plot(F2); dwf_fits(F2,"F2");
Chen jingyuan, Gan guangyong (IAPCM, Beijing,China.)
rectang , rect_screen , gauss , hex_ap , rect_ap , annul_ap , aperture ,