1)How to calculate this integral, because I have some very small values (10^-20) in solution and values on this position in matrix should be equal to zero. If I can not do that with working precision, how to set automatically this values to be zero in matrix for further?
2)Also there is a problem, because I don't know what is a true. Maybe mathematica is wrong because of precision, if it is not (I suppose), I want to set this values to be zero.
3)This command is not numerical integration, but can I use parallelize or other ways to obtaining the solution faster?
Here is a file:
Thank you very much in advance