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Hi Dave,
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<div class="">Thank you very much for your reply. That is indeed the problem. I have been working with matrices in Slepc but I don’t really understand it. I tried to preallocate but it still does not work. If you look at my code below:</div>
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<div class="">ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);</div>
<div class="">ierr = MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,h_dim,h_dim);<span class="Apple-tab-span" style="white-space:pre">
</span> // h_dim is the dimension of the square matrix A</div>
<div class="">ierr = MatSetFromOptions(A);CHKERRQ(ierr);</div>
<div class="">ierr = MatSetUp(A);CHKERRQ(ierr);</div>
<div class="">ierr = MatGetOwnershipRange(A,&Istart,&Iend);CHKERRQ(ierr);</div>
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<div class="">MatSeqAIJSetPreallocation(A,0,nnz);
<span class="Apple-tab-span" style="white-space:pre"></span>// I try to preallocate here, where nnz is the array containing the number of non-zero entries each row</div>
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<div class="">for (int i=0;i<row.size();i++) {</div>
<div class=""><span class="Apple-tab-span" style="white-space:pre"></span>MatSetValue(A,row[i],column[i],h[i],INSERT_VALUES);</div>
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<div class="">I am not sure what other information I need to give for the pre-allocation…</div>
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<div class="">Cheers,</div>
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<div class="">Yang Bo</div>
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<blockquote type="cite" class="">
<div class="">On 21 May 2020, at 4:08 PM, Dave May <<a href="mailto:dave.mayhem23@gmail.com" class="">dave.mayhem23@gmail.com</a>> wrote:</div>
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<div class=""><b style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class="">-info
| grep malloc</b></div>
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