Slow DSS solver

Slow DSS solver

Hello everone!

I have two questions about DSS solver.
1. Why is the first use of dss_reorder( ) VERY SLOW? For a matrix 1300x1300 with only 5000nnz I had to stop my program because it hunged (even for a matrix of size 7 it takes about a second or two to reorder) Is this normal, or I am doing some kind of a mistake....

2. What could possibly be a couse of an error "MKL-DSS-DSS-Error, An unclassifiable error occured"? I get it while using several time the routine for solving which is almost identical to an example program in dss_sym. It always crashes on reordering routine and it occures in unpredictable moments. This happens during solving the same system in each routine call.

Thank you in advance for any answer


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First of all, thanks for trying out DSS.

It is difficult to diagnose this issue with the information given. DSS should be fast and should reorder that matrix efficiently.

I would suggest reporting this to Intel Premier support with a suitable example.


Hi Peter

The DSS solver is based on PARDISO and I am one of the authors. Do you haveany dense rows or columns in the sparse systems. This might be a problem in theMKL Pardiso Version.

I am interested in the problem. Could you please send me the system?

Olaf Schenk
CS Department
University of Basel

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