<div dir="ltr"><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">Hello,</div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">I'm trying to solve for the first ten smallest eigenvalues of a diffusion equation in a 3d heterogeneous medium (varying diffusion coefficient), but I'm getting an error message:</div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Traceback (most recent call last):<br>  File "eigendrake_spe10_v2.py", line 121, in <module><br>    es.solve()<br>  File "SLEPc/EPS.pyx", line 1132, in slepc4py.SLEPc.EPS.solve<br>petsc4py.PETSc.Error: error code 55<br>[0] EPSSolve() line 136 in /tmp/pip-req-build-6t_4bkg3/src/eps/interface/epssolve.c<br>[0] EPSSetUp() line 269 in /tmp/pip-req-build-6t_4bkg3/src/eps/interface/epssetup.c<br>[0] STSetUp() line 271 in /tmp/pip-req-build-6t_4bkg3/src/sys/classes/st/interface/stsolve.c<br>[0] STSetUp_Shift() line 119 in /tmp/pip-req-build-6t_4bkg3/src/sys/classes/st/impls/shift/shift.c<br>[0] KSPSetUp() line 391 in /tmp/pip-req-build-070lpqqd/src/ksp/ksp/interface/itfunc.c<br>[0] PCSetUp() line 932 in /tmp/pip-req-build-070lpqqd/src/ksp/pc/interface/precon.c<br>[0] PCSetUp_LU() line 99 in /tmp/pip-req-build-070lpqqd/src/ksp/pc/impls/factor/lu/lu.c<br>[0] MatLUFactorSymbolic() line 3111 in /tmp/pip-req-build-070lpqqd/src/mat/interface/matrix.c<br>[0] MatLUFactorSymbolic_SeqAIJ() line 366 in /tmp/pip-req-build-070lpqqd/src/mat/impls/aij/seq/aijfact.c<br>[0] PetscMallocA() line 390 in /tmp/pip-req-build-070lpqqd/src/sys/memory/mal.c<br>[0] MatLUFactorSymbolic_SeqAIJ() line 366 in /tmp/pip-req-build-070lpqqd/src/mat/impls/aij/seq/aijfact.c<br>[0] Out of memory. Allocated: 0, Used by process: 14097043456<br>[0] Memory requested 18446744069467867136</blockquote></blockquote></div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">I'm using code from <a href="https://www.firedrakeproject.org/" target="_blank">Firedrake Project</a> (finite-element method) to discretize the equations.</div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">My code is available here: <a href="https://github.com/rbpiccinini/codes/blob/master/eigendrake/eigendrake_spe10_v2.py" target="_blank">https://github.com/rbpiccinini/codes/blob/master/eigendrake/eigendrake_spe10_v2.py</a></div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">The code was run with 64GB available as RAM memory. The requested memory seems to be abnormally high, though.</div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">I'm able to solve for the eigenvalues of a 2d smaller problem. However, if I try to solve the 3d problem, I get the out of memory error.</div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">Could anybody help me understand the issue?</div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br></div><div class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature">Thanks in advance.</div><div dir="ltr" class="m_1645492619721453989gmail_signature" data-smartmail="gmail_signature"><br>--<br>Rodrigo</div></div>