MKL / PARDISO Multithreading Issue

[Roman_S_7]

Hello!

I am using PARDISO for factorization of symmetrical complex matrices. Recently I downloaded evaluation library v. 11.2 upd3 and run a code that was developed for v.10 library some time ago. It solves the problem with success but only with 1 thread. I.e. I failed to enable multithreading for PARDISO. Last time I used OMP_NUM_THREADS variable and it was ok.

How can I enable multithreading? Can the evaluation (trial) license be locked for more than 1 thread?

Environment:

• Win7 OS

• MS Visual Studio 2010 C++

• Desktop PC with Intel i5 CPU

Pardiso iparm:

iparm[0] = 0; // No solver default.

iparm[1] = 3; // The parallel (OpenMP) version of the nested dissection algorithm

iparm[2] = 0; //

iparm[3] = 0; // No iterative-direct algorithm.

iparm[4] = 0; // No user fill-in reducing permutation.

iparm[5] = 0; // Write solution into x.

iparm[6] = 0; // Not in use.

iparm[7] = 2; // Max numbers of iterative refinement steps.

iparm[8] = 0; // Not in use.

iparm[9] = 13; // Perturb the pivot elements with 1E-13.

iparm[10] = 1; // Use nonsymmetric permutation and scaling MPS.

iparm[11] = 0; // Not in use.

iparm[12] = 0; // Not in use.

iparm[13] = 0; // Output: Number of perturbed pivots.

iparm[14] = 0; // Not in use.

iparm[15] = 0; // Not in use.

iparm[16] = 0; // Not in use.

iparm[17] = -1; // Output: Number of nonzeros in the factor LU.

iparm[18] = -1; // Output: Mflops for LU factorization.

iparm[19] = 0; // Output: Numbers of CG Iterations.

Task: Reordering + factorization of Complex symmetrical matrix;

Goal: multithread run within OpenMP paradigm

I tried following methods for multithreading:

• Set environment variable OMP_NUM_THREADS– does not work (process uses 1 thread/CPU kernel)

• Set variable MKL_NUM_THREADS– does not work (process uses 1 thread)

• Call function omp_set_num_threads(num_threads) – does not work (process uses 1 thread)

• Call function mkl_set_num_thread(num threads) – does not work (process uses 1 thread)

All “*_set_num_thread” functions call are in the main() before calling any Pardiso routine. Variables are set for the process or in the main function.

Thank you in advance.

[Gennady_F_Intel]

Roman, the evaluation version of MKL is the same as the product version. How do you link your application? it looks like you linked sequential threading libs. 

[Roman_S_7]

Thank you for answer!

It seems so. Could you tell me please, what libraries are necessary to link in order to use PARDISO in a parallel? I mean, static libs?

[Gennady_F_Intel]

static or dynamic - doesn't make a sense from threading point of view.  Please refer to the mkl linker adviser follow with the link: https://software.intel.com/en-us/articles/intel-mkl-link-line-advisor/  to find how to link with threading version. 

[Roman_S_7]

The link is very helpful. Thanks a lot!