https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-BSR3-VBSR-variations/m-p/1697390#M37217 <P>Hello. I used MKL 2024.0 in this test. I tried VBSR variant with mtype=2 with a matrix about 100'000 unknowns and default parameters. It worked fine with CSR3 format and VBSR with iparm[36]=-95. Then I specified iparm[36]=-1 just to see what happens and it also computed the solution with good relative residual 1e-13 but percentage statistics was broken:</P><P>...<BR />1143 %<BR />1149 %<BR />1154 %<BR />1156 %<BR />100 %<BR />However, the solver should be terminated in this case, because if it merges all rows with at least 1% similarity into supernodes, the matrix should be almost dense and solver should break with error like "non enough memory", which it did on some another matrix. The solver may actually&nbsp; behave the other way in this case, for example, specify block size -iparm[36] in VBSR, so this should be either documented or fixed.<BR />I also have a question about MKL BSR3 format (iparm[36]&gt;0). MKL 2024.2 documentation states that "Intel ® oneAPI Math Kernel Library (oneMKL) supports only the VBSR format for real and symmetric positive definite or indefinite matrices (mtype = 2 or mtype = -2).". Is that correct the user cannot use in PARDISO any symmetric BSR3 format to factorize a symmetric matrix?&nbsp; However, when I specify iparm[36]=1, it works fine. Do I have to convert the matrix to unsymmetric BSR3 format in order to use to use BSR3 solver even for an SPD matrix&nbsp; and solve with mtype=11?</P><P>&nbsp;</P> Mon, 16 Jun 2025 04:36:26 GMT morskaya_svinka_1 2025-06-16T04:36:26Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-BSR3-VBSR-variations/m-p/1697390#M37217 <P>Hello. I used MKL 2024.0 in this test. I tried VBSR variant with mtype=2 with a matrix about 100'000 unknowns and default parameters. It worked fine with CSR3 format and VBSR with iparm[36]=-95. Then I specified iparm[36]=-1 just to see what happens and it also computed the solution with good relative residual 1e-13 but percentage statistics was broken:</P><P>...<BR />1143 %<BR />1149 %<BR />1154 %<BR />1156 %<BR />100 %<BR />However, the solver should be terminated in this case, because if it merges all rows with at least 1% similarity into supernodes, the matrix should be almost dense and solver should break with error like "non enough memory", which it did on some another matrix. The solver may actually&nbsp; behave the other way in this case, for example, specify block size -iparm[36] in VBSR, so this should be either documented or fixed.<BR />I also have a question about MKL BSR3 format (iparm[36]&gt;0). MKL 2024.2 documentation states that "Intel ® oneAPI Math Kernel Library (oneMKL) supports only the VBSR format for real and symmetric positive definite or indefinite matrices (mtype = 2 or mtype = -2).". Is that correct the user cannot use in PARDISO any symmetric BSR3 format to factorize a symmetric matrix?&nbsp; However, when I specify iparm[36]=1, it works fine. Do I have to convert the matrix to unsymmetric BSR3 format in order to use to use BSR3 solver even for an SPD matrix&nbsp; and solve with mtype=11?</P><P>&nbsp;</P> Mon, 16 Jun 2025 04:36:26 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/PARDISO-BSR3-VBSR-variations/m-p/1697390#M37217 morskaya_svinka_1 2025-06-16T04:36:26Z