I use MKL 10.1 to solve sparse linear system. System is symmetric and positive definite but during phase 22 PARDISO fails with error code -1 and message is 'Error in PARDISO: zero or negative pivot, A is not SPD-matrix'
Can anyone help me to find the reason for this error? I have attached a part of code from my software and some statistical information printed by PARDISO. Please see the attachment. Please find the sparse matrix at the end of this mail.
That means sparse matrix structure is correct. I too solved this matrix by modifying MKL sample program. Its strange
that it did not give any such error and easily factorised the matrix in phase 22. After you pointed out, I made sure that all the data and data type are
same in both MKL sample program and my software.
As a matter of fact, I have been using this code for solving sparse system for quite some time. Recently, I made changes to add few more terms in coefficient matrix. Since, then I have been getting such error.
Can you suggest some way to get more information on what is going wrong?
I found that there was a problem while assembling the matrix which made it indefinite. I had a print statement in my code to output content which was truncating the double till 6 digit places after decimal. And this made matrix look like positive definite. I printed some more decimal places in matrix and found that it is not positive definite.