https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Problem-in-MKL-example-for-CG-with-SSOR/m-p/1104006#M24039 <P>I think there is something wrong with the sample "cg_ssor_precon_c.c" in the for loop that applies the SSOR iteration. The purpose of the loop is to apply SSOR repeatedly on the array &amp;tmp[3*n]. but inside the loop every time it starts using tmp[2*n] and overwrites the previous value in tmp[3*n]. So effectively the loop is equivalent to a single SSOR run regardless of the number of iterations desired.</P> <P><SPAN style="font-size: 1em;">Can somebody help me confirm this?</SPAN></P> Wed, 10 May 2017 21:04:40 GMT Tysseer_H_ 2017-05-10T21:04:40Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Problem-in-MKL-example-for-CG-with-SSOR/m-p/1104006#M24039 <P>I think there is something wrong with the sample "cg_ssor_precon_c.c" in the for loop that applies the SSOR iteration. The purpose of the loop is to apply SSOR repeatedly on the array &amp;tmp[3*n]. but inside the loop every time it starts using tmp[2*n] and overwrites the previous value in tmp[3*n]. So effectively the loop is equivalent to a single SSOR run regardless of the number of iterations desired.</P> <P><SPAN style="font-size: 1em;">Can somebody help me confirm this?</SPAN></P> Wed, 10 May 2017 21:04:40 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Problem-in-MKL-example-for-CG-with-SSOR/m-p/1104006#M24039 Tysseer_H_ 2017-05-10T21:04:40Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Problem-in-MKL-example-for-CG-with-SSOR/m-p/1104007#M24040 <P>Do you mean snippet from line 208 to line 228 in the c file?</P> <P>tmp[3*n] will be updated in the function call mkl_dcsrsv (line 225).</P> <P>In the function call mkl_dcsrmv (line 221), tmp[3*n] is used as input, so in each iteration, tmp[3*n] will be updated and the inputs to mkl_dcsrmv are different.</P> Fri, 12 May 2017 07:41:35 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Problem-in-MKL-example-for-CG-with-SSOR/m-p/1104007#M24040 Jing_Xu 2017-05-12T07:41:35Z