Hi,

I am going to change my solver from TDMA to GMRES. Does anyone know which one is faster. I do not want to waiste my time by changing my solver.

Is there any big difference in CPU time if I use GMRES?

Regards,

GMRES by itself is very inefficient (as far as my experience goes). It needs a good preconditioner. So you must have some knowledge about preconditioners.

If you are using TMDA, I guess your matrix is triangular. TMDA is the best scheme in this case.

Yes I agree with raju and praveen. If you have a tridiagonal matrix keep on using the TDMA which has been specifically developed. As raju said GMRES is not the solution to every problem! You need a good preconditioner to reduce the number of iteration and you may run out of memory is you have many degrees of freedom. Luca