Threaded version of Pardiso

[farukhsharipov]

We are using Intel Visual Fortran Composer XE 2011 with MKL library, and we trying to solve large matrices using pardiso using multithread enabled but it's not working. When runing mkl_get_max_threads() it shows only 2 instead of 4 even if we use call mkl_set_num_threads(4) it still shows 2 and we can see from Task Manager that not all the threads are working 100% just 20% and only sometime...

We set

iparm(2) = 3 ! fill-in reordering from METIS

iparm(3) = 4 ! numbers of processors

This is runing on Intel Core i7 with 2 Cores and 4 Threads 

Can anyone please advise why this is not working?

Thanks in advance.

[Zhang_Z_Intel]

Currently, iparm(3) is not supported in Intel MKL PARDISO. Do not use it to set the number of threads. Instead, you should use either the support function mkl_set_num_threads, or the environment variable MKL_NUM_THREADS.

Please try this before you call pardiso:

mkl_set_dynamic(0);
mkl_set_num_threads(4);

Let us know if it works.You can also check the output statistics from PARDISO to see how many threads are actually used. You'd look for a line in the output that starts with "< Parallel Direct Factorization with number of processors: >".