10
I have a Mathematica code where I have to evaluate numerically thousands of integrals similar to this one
NIntegrate[
(Pi*Cos[(Pi*(-2*x + y))/(1 + y)] + (1 + y)*(-Sin[(2*Pi*x)/(1 + y)] +
Sin[(Pi*(-2*x + y))/(1 + y)]))/(E^x*(1 + y)),
{x, 0, 100}, {y, 0, 100}
] //AbsoluteTiming
The integrand is a nice absolutely integrable function without singularities, which decays exponentially in one direction and as 1/y^3 in the other direction.
The NIntegrate command was working fine in Mathematica 7, but in the newest version 8.0.4 it slows down by two orders of magnitude. I assume in the new version it tries to better control the error, but at the expense of this tremendous increase in time. Are there some settings I could use so that the computation proceeds with the same speed as in Mathematica 7?