[petsc-users] Problem when switching from debug to optimized

Bogdan Dita bogdan at lmn.pub.ro
Mon Nov 14 06:02:06 CST 2011


  Hello,

  Below is my post from a few days ago and this time I've attached the
output from log_summary.
"
  Until a few days ago I've only be using PETSc in debug mode and when I
switch to the optimised version(--with-debugging=0) I got a strange
result regarding the solve time, what I mean is that it was 10-15 %
higher then in debug mode.
  I'm trying to solve a linear system in parallel with superlu_dist, and
I've tested my program on a Beowulf cluster, so far only using a single
node with 2 quad-core Intel processors.
  From what I know the "no debug" version should be faster and I know it
should be faster because on my laptop(dual-core Intel) for the same
program and even the same matrices the solve time for the optimised
version is 2 times faster, but when I use the cluster the optimised
version time is slower then the debug version.
  Any thoughts?

"
  Best regards,
  Bogdan Dita



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