https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806162#M3431 Hi,<DIV>It's depend on type of your matrix H and H-tI. Are they always positive defined or not?</DIV><DIV>With best regards,</DIV><DIV>Alexander Kalinkin</DIV> Sun, 19 Feb 2012 07:49:43 GMT Alexander_K_Intel2 2012-02-19T07:49:43Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806161#M3430 Hi,<BR />=-=<BR /><BR />I am trying to solve a large and sparse system of linear equations with multiple right hand sides using pardiso in mkl. The system has a structure (H-tI)x=b, where H is the large sparse matrix (symmetric), t is a real number and I is the unit matrix. I need the solution for several different values of the parameter t. Therefore, in every case only the diagonal elements change, the rest of the matrix is untouched. The right hand side is the same in all cases as well. I would like to know, whether it is enough to perform the symbolic factorization (phase 1) only once or whether it is necessary to perform it every time I change the value of t again and again.<BR /><BR />Thank you for any reaction.<BR /> Michal Sun, 19 Feb 2012 07:44:55 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806161#M3430 Michal_Tarana 2012-02-19T07:44:55Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806162#M3431 Hi,<DIV>It's depend on type of your matrix H and H-tI. Are they always positive defined or not?</DIV><DIV>With best regards,</DIV><DIV>Alexander Kalinkin</DIV> Sun, 19 Feb 2012 07:49:43 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806162#M3431 Alexander_K_Intel2 2012-02-19T07:49:43Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806163#M3432 Matrix H is postive definite and H-tI can be indefinite. I use mtype=-2. Thank you for your flexible reaction.<BR /><BR />Michal Sun, 19 Feb 2012 08:30:48 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806163#M3432 Michal_Tarana 2012-02-19T08:30:48Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806164#M3433 In such case you need to use mtype = -2 for all cases and disable scaling and matching (iparm(11) and iparm(13)). But if you disable them for some matrices (for example indefinite or near indefinite) result will be quite wrong so I recommend you to use symbolic factorization for each matrix.<DIV>With best regards,</DIV><DIV>Alexander Kalinkin</DIV> Sun, 19 Feb 2012 08:37:09 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806164#M3433 Alexander_K_Intel2 2012-02-19T08:37:09Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806165#M3434 Thank you.<BR />Michal Sun, 19 Feb 2012 08:41:58 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-for-multiple-matrices/m-p/806165#M3434 Michal_Tarana 2012-02-19T08:41:58Z