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<p>Hello,</p>
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<p>I am using TSSolve to solve a linear problem. </p>
<p>In the FormIJacobian function that I provide to TSSetIJacobian, I first set the coefficients of both J and Jpre matrices the same way (J and Jpre matrices are equal in the first step). Then I call MatAXPY to prepare Jpre (Jpre := Jpre - another_matrix. So,
Jpre and J are not equal anymore). </p>
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<p>But I get the error once FormIJacobian is called the second time inside TSSolve: </p>
<p>"[0]PETSC ERROR: New nonzero at (5,1) caused a malloc</p>
<p>Use MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE) to turn off this check".</p>
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<p>It looks like MatAXPY changes the allocation of Jpre, which the second FormIJacobian does not like unless Jpre is destroyed first.</p>
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<p>Do you have any suggestions to fix this malloc issue? </p>
<p>Thanks.</p>
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<p>Best regards,</p>
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<p>Zakariae</p>
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