Thanks a lot, I'm using petsc since 2004
On 7/11/2024 5:09 PM, Barry Smith wrote:
The default behavior previously was the flip of the current
behavior. By the way, we also now have much better performance if you
do not preallocate (not as good as with perfect preallocation, but
much better than in ancient history; you simply do not preallocate to
get this behavior).
Barry
On Jul 11, 2024, at 4:51 PM, Michael Povolotskyi <mpovo...@gmail.com>
wrote:
Thanks a lot.
Is this a new feature? It seems to me that 10 years ago the default
behavior was different.
Michael.
On 7/11/2024 4:04 PM, Barry Smith wrote:
By default, if you preallocate but not enough, it will
automatically error unless you call
MatSetOption(mat,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
On Jul 11, 2024, at 4:02 PM, Michael Povolotskyi
<mpovo...@gmail.com> wrote:
Thank you,
let me clarify my question.
Imagine that I have a sparse matrix, and the number of non zero
entries that I specified is too small.
I know that I can insert values in it but it will be slow.
I remember there was a way to make PETSC to throw an error if a
number of non zero elements per row was bigger that was
preallocated. Then I could fix my algorithm. Is this functionality
available with the current version?
Michael.
On 7/11/2024 3:55 PM, Barry Smith wrote:
MatGetInfo() is the programmatic interface used to get this
information. You can also run a proggram with -info and grep for
malloc.
Barry
On Jul 11, 2024, at 1:55 PM, Michael Povolotskyi
<mpovo...@gmail.com> wrote:
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Hello,
is there an option in PETSC that allows to check at run time if a sparse
matrix has been preallocated correctly? I remember there was something
like that is the older versions, but cannot find it now.
The goal is to get rid of any possible time overhead due to dynamic
preallocation.
Thank you,
Michael.
