I was thinking about computing the discrepancy (for different numbers of
samples), to see what are the best values for count with the current samples
data in pov
I found a description to compute the star discrepancy, but only for uniform
distribution in a unit square
http://mathworld.wolfram.com/StarDiscrepancy.html
http://ina.eivd.ch/Collaborateurs/etr/research.html

As i don't know how to adapt it for a disc, I decided to map the disc to a
square
(x,y) the sample in the disc gives nx=x*x+y*y and ny=atan2(y,x)/(2*pi)+.5 in
the square unit

But when applying this transformation to povray samples I get those bad
looking results (at least for small N)
http://195.221.122.126/samples/rad_square010.jpg
http://195.221.122.126/samples/rad_square020.jpg
http://195.221.122.126/samples/rad_square050.jpg
http://195.221.122.126/samples/rad_square100.jpg

So I wonder if it's a good way to measure the discrepancy
Or is the povray distribution not that good ?

M

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Mael wrote:
> As i don't know how to adapt it for a disc, I decided to map the disc to a
> square

That would distort the disc in all sorts of ways, so the bad results aren't
surprising.

Anders

--
#macro E(D)(#if(D<2)D#else#declare I=I+1;mod(pow(.5mod(I 6))*asc(substr(
"X0(1X([\\&Q@TV'YDGU`3F(-V[6Y4aL4XFUTD#N#F8\\A+F1BFO4`#bJN61EM8PFSbFA?C"
I/6 1))2)<1#end)#end#macro R(D,I,T,X,Y)#if(E(D))R(D-1I,T,Y/2X)R(D-1I,T+Y
/2Y/2X)#else box{T T+X+Y pigment{rgb E(2)*9}}#end#end R(10,5z*3-1v*2u*2)

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