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https://software.intel.com/en-us/recent/554807
enSparse Matrix Structure leads Zero Pivot Error
https://software.intel.com/en-us/forums/topic/471780
<p>Hi all,</p>
<p>I am using the DSS from MKL to solve the linear system of equations Ax=b, for which the resulting matrix A is sparse and not symmetric, but its structure is symmetric.</p>
<p>Concerning the options, I am using MKL_DSS_SYMMETRIC_STRUCTURE in the definition of the structure and MKL_DSS_INDEFINITE in the factorization.</p>
<p> I am using the following example (15*15 matrix in attachment) to try and solve a system considering that the matrix A is sparse. Unfortunately, the DSS solver gives an error of “MKL-DSS-DSS-Error, Zero Pivot detected”, but the matrix is non-singular. The determinant of the matrix is about -3.1e+62 (calculated in excel) and I get the solution both in excel and matlab.</p>
<p>When I switch the definition of the matrix structure for MKL_DSS_NON_SYMMETRIC, I get the correct solution. I don’t understand why!</p>
<p>In order to understand this problem I create a new subroutine. Using the initial definition of matrix structure, I give all elements of A as non-zero (dense matrix), I am not take advantage of the sparse matrix. With this structure, DSS solver gives the correct solution.</p>
<p>Someone can help me why I cannot use the MKL_DSS_SYMMETRIC_STRUCTURE definition in the sparse matrix structure.</p>
<p>Both subroutines are in attachment.</p>
<p>Thank you.</p>
<p>Diogo</p>
Tue, 03 Sep 13 10:01:21 -0700diogoneto471780