pardiso residual

[Humphrey]

Dear mkl experts,

I get a problem when I am trying to solve a linear system with pardiso. The relative residual(||Ax-b||/||b||, A is a 2000000 * 2000000 sparse matrix)is always maintained at 0.001072 and I want to get a more accurate result. Here is the iparm values:

iparm[0] = 1; 
iparm[1] = 3;

iparm[7] = 100;

iparm[9] = 13;

iparm[10] = 1;

iparm[12] = 1;

iparm[17] = -1;

iparm[18] = -1;

iparm[23] = 1;

iparm[26] = 1;

iparm[31] = 1;

iparm[33] = 8;

iparm[34] = 1;

How should I adjust the iparm values? Your help appreciated.

[Ruqiu_C_Intel]

Hi,

Generally, if your input matrices with large condition numbers, then solver matrices would have better accuracy output. Can you check your input matrix? And could you please attach a simple reproducer, then you might get help from other MKL users in this community?