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</o:shapelayout></xml><![endif]--></head><body lang=DE link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hey,<o:p></o:p></p><p class=MsoNormal><span lang=EN-US>i have a precomputed scipy sparse matrix for which I want to solve the eigenvalue problem for a matrix of size 35000x35000. I donīt really get how to parallelize this problem correctly. <br>Similar to another thread(<a href="https://lists.mcs.anl.gov/mailman/htdig/petsc-users/2013-August/018501.html">https://lists.mcs.anl.gov/mailman/htdig/petsc-users/2013-August/018501.html</a>) I tried the following code:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal>D = scipy.sparse.load_npz("sparse.npz")<o:p></o:p></p><p class=MsoNormal><span lang=EN-US>B = D.tocsr()<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US># Construct the matrix Ds in parallel<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Ds = PETSc.Mat().create()<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Ds.setSizes(CSRmatrix.shape)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Ds.assemble()<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US># Fill the matrix<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>rstart, rend = Ds.getOwnershipRange()<o:p></o:p></span></p><p class=MsoNormal>csr = (<o:p></o:p></p><p class=MsoNormal> B.indptr[rstart:rend+1] - B.indptr[rstart],<o:p></o:p></p><p class=MsoNormal> B.indices[B.indptr[rstart]:B.indptr[rend]],<o:p></o:p></p><p class=MsoNormal> B.data[B.indptr[rstart]:B.indptr[rend]]<o:p></o:p></p><p class=MsoNormal><span lang=EN-US>)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Ds = PETSc.Mat().createAIJ(size=CSRmatrix.shape, csr=csr)<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Ds.assemble()<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US># Solve the eigenvalue problem<o:p></o:p></span></p><p class=MsoNormal>solve_eigensystem(Ds)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US>This code works for 1 processor with mpiexec –n 1 python example.py, however for increasing number of processors it appears as if al processors try to solve the overall problem instead of splitting it into blocks and solve for a subset of eigenvalues and eigenvectors. <br>Why is this the case or did I miss something? <br><br><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Greetings Jan <o:p></o:p></span></p></div></body></html>