Make an animated gif of a Mandelbrot Fractal pattern in R

[Paul Johnson <>]

In the R-help list,  Jarek Tuszynski, PhD. (Jaroslaw.W.Tuszynski AT 
saic.com,  Science Applications International Corporation) just posted 
this neat R code. Assuming you have "fields" and "caTools" packages 
installed, then this creates an animated gif output file. If you view in 
your web browser, the output file "Mandelbrot.gif" is truly amazing.  My 
mail program was translating one part of this into an R mistake, and I 
expect yours will too. So I'm correcting that part and posting here. You 
should be able to just cut and paste this whole section into a running R 
and get the result. The R screen does not show the animated gif. It is 
necessary to view the output file in a web browser.



library(fields)  # for tim.colors
library(caTools) # for write.gif
m = 400          # grid size
C = complex( real=rep(seq(-1.8,0.6, length.out=m), each=m ),
             imag=rep(seq(-1.2,1.2, length.out=m),      m ) )
C = matrix(C,m,m)
Z = 0
X = array(0, c(m,m,20))
for (k in 1:20) {
  Z = Z * Z +C
  X[,,k] = exp(-abs(Z))
}
image(X[,,k], col=tim.colors(256)) # show final image in R
write.gif(X, "Mandelbrot.gif", col=tim.colors(256), delay=100)

pj

--
Paul E. Johnson                       email: pauljohn_AT_ku.edu
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
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