I'm no longer certain how this mistake crept into the code ; previously the variable u was being assigned a different value every time an iteration was completed. This is a more correct version ; doesn't , at the moment, produce such an interesting fractal ; however the results are now more accurate than previously. I do however have a question . The formula for Newton's Method is: x Pd } comment { The floating point option needs to be selected , 512 iterations , or more , should be selected . Also a logarithmic palette . Minibrot structures aren't immediately apparent at the default parameter settings . A parameter setting of : xmin - 0.005770310598 xmax - 0.005666943901 ymin 0.000516417395 ymax 0.000594104392 shows embedded mimibrots and spirals , wether this is relevant in a real diode is unknown . You might be able to locate mimibrots elsewhere on the map . } ========END PARAMETER FILE==================