topic memory overwrite when using cluster solver with one MPI process in Intel® oneAPI Math Kernel Library

memory overwrite when using cluster solver with one MPI process

Charlotte_Ching — Mon, 26 Jun 2023 04:44:39 GMT

I tried to run cluster solver with one MPI process to solve a symmetric sparse linear system.

The software settings are:

mkl 2022.2.0
windows 10
c++

The parameter are defined as follows

iparm[0] = 1; // no solver default iparm[1] = 3; // parallel version of the nested dissection algorithm iparm[5] = 1; // write solution to b iparm[7] = 2; // max numbers of iterative refinement steps iparm[9] = 8; // perturb pivot tolerance iparm[10] = 1; // use nonsymmetric permutation and scaling MPS iparm[12] = 1; // maximum weighted matching iparm[27] = 0; // double precision iparm[34] = 1; // C-style indexing iparm[39] = 2; // distributed input iparm[59] = 0; // cluster sparse solver mode

Since we write solution to b, I suppose the input for solution can be a dummy double. So I create a dummy double `ddum` and use `&ddum` as input for solution .

It works when I run with multiple processes. However, if I run with single process, it will overwrite the memory at the address of the solution. I check the length of the overwritten memory, it is of the size of the linear system (The example I test is 1188). I tried with a very small matrix (3x3), it did not give me any error.

Could anyone help me with the problem?

Re: memory overwrite when using cluster solver with one MPI process

VarshaS_Intel — Tue, 27 Jun 2023 11:15:05 GMT

Hi,

Thanks for posting in Intel Communities.

We had tried with the sample example(C:\Program Files (x86)\Intel\oneAPI\mkl\latest\examples\examples_cluster_c.zip\c_mpi\cluster_sparse_solver\source\cl_solver_sym_sp_0_based_c.c) where it is using cluster_sparse_solver, we are able to run the code without any errors with single and multiple processes.

Could you please provide us with the complete sample reproducer code(data file if any) along with the steps if you had followed to investigate more on your issue?

Thanks & Regards,

Varsha

Re: memory overwrite when using cluster solver with one MPI process

Charlotte_Ching — Wed, 28 Jun 2023 05:54:33 GMT

Thank you for your reply.

For the example you tested, you can try set ipam[5] = 1 (write solution to b) and print the x array. Cluster solver will write values to x as well.

Re:memory overwrite when using cluster solver with one MPI process

VarshaS_Intel — Fri, 30 Jun 2023 18:21:17 GMT

Hi,

Thanks for your reply.

Could you please let us know what exact errors you are getting at the time of running the code on a single process?

And also, could you please let us know what compilation and running commands you are using for your code?

Thanks & Regards,

Varsha

Re:memory overwrite when using cluster solver with one MPI process

VarshaS_Intel — Mon, 10 Jul 2023 10:07:46 GMT

Hi,

We have not heard back from you. Could you please let us know what exact errors you are getting at the time of running the code on a single process?

And also, could you please let us know what compilation and running commands you are using for your code?

Thanks & Regards,

Varsha