Hi,
This code below works.
But it should give circles outside unit cirle.
The most inner curve is not a cirle.
Where is error ?
Adam
== Code =============================================
/* Mario Rodriguez */
GiveSLogPhi(zre, zim,c,e_r,i_max):=
block(
[z:zre+%i*zim, logphi, fac:1/2, i:0],
while i<i_max and cabs(z)<e_r do
(z:z*z+c,
fac:fac/2,
i:i+1 ),
if i=i_max
then logphi:0
else logphi:fac*log(cabs(z)),
float(logphi) )$
fun(x,y):= GiveSLogPhi(x,y,0,10,500)$
load(draw) $
draw3d(
explicit(fun, zx,-2.5,2.5,zy,-2.5,2.5),
contour = map,
contour_levels = {1.0, 0.5, 0.1, 0.01}
);