Re: Computing zero set of function of two variables


glen herrmannsfeldt wrote:
veda wrote:

Lets say you have a function of two variables (z=z(x,y) )available to
you defined on a "grid" of points (x_i,y_i ), say, uniformly spaced on
the domain

(snip)

Using the "grid" (note that these are not finite elements, merely
square grid of points), how do you compute the curve(s) that represent
the set of points where z=0 on the domain?

There are routines to do contour plots. That sounds like what you want.

I believe there is a routine in
http://ftp.riken.go.jp/pub/iris/ugs/ugs.tar.gz

I would call Gnuplot (a good, free, and portable graphing program) from
Fortran using the "system" command (an extension present in most
Fortran compilers) to create contour plots, or on Unix, using
gnuplotfortran http://sourceforge.net/projects/gnuplotfortran .

.

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