Integral3 is taking forever to finish computing integral

I have the following code:

fun = @(x,y,z,r,s,t) log((r.*s.*t).^2+1-2.*r.*s.*t*cos(x+y+z)).*cos(x+y+z)./(r.*s.*t);
A=integral3(@(r,s,t)arrayfun(@(r,s,t)integral3(@(x,y,z)fun(x,y,z,r,s,t),0,2*pi,0,2*pi,0,2*pi),r,s,t),1.01,100,1.01,100,1.01,100);
%B=integral3(@(r,s,t)arrayfun(@(r,s,t)integral3(@(x,y,z)fun(x,y,z,r,s,t),0,2*pi,0,2*pi,0,2*pi),r,s,t),0.1,.9,0.1,.9,0.1,.9,);
A

The value of A is not showing up even after half an hour. I wonder if there's something wrong with my code or it's just that this nested integral really takes some time to compute. Any help is greatly appreciated. Thanks!

Answer 1

[Walter Roberson]

The nested integral (6 total levels) just takes a long time to compute.

[Walter Roberson]

I have had the calculation going for the last 10 days, but it shows no sign of being finished any time soon.