<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2900.2769" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>Sorry, Herbert, but it doesn't work.</FONT></DIV>
<DIV><FONT face=Arial size=2>First, the /func definition has a
mistake:</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV> 1 x 2 exp yVal 2 exp add sqrt %
1/sqrt(x^2+y^2)<BR> 1 x 10 sub 2 exp yVal 2 exp
add sqrt % 1/sqrt((x-10)^2+y^2)</DIV>
<DIV><BR><FONT face=Arial size=2>must be replaced by</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV> 1 x 2 exp yVal 2 exp add sqrt div%
1/sqrt(x^2+y^2)<BR> 1 x 10 sub 2 exp yVal 2 exp
add sqrt div % 1/sqrt((x-10)^2+y^2)</DIV>
<DIV> </DIV>
<DIV>(the inverse of the square root), and the error message reported by
the ps viewer (gsview 4.7 with ghostscript 8.53) is the same I have obtained in
the past.</DIV>
<DIV>You say that maybe the Steffensen algorithm is not the best tool in this
case. What is the way to draw these equipotential lines?</DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Another question: the \psplot used in this example
contains the 'polarplot' option, and we are using Cartesian coordinates.
Why? I have used both options, Cartesian and polarplot, but I just obtained the
same error message.</FONT></DIV>
<DIV><FONT face=Arial size=2>Thanks by your interest.</FONT></DIV>
<DIV><FONT face=Arial size=2>Oscar Ecenarro</FONT></DIV></BODY></HTML>