Hey,
I've modified my code that it counts the total number of non-zeros (trivial to
put in the preallocation code) and decides upon that wheather to create a
MATSBAIJ or MATDENSE matrix.
Using sparse matrices (for one that is really dense) I've made good experiences
with -pc_factor_shift_type
On Nov 7, 2014, at 7:03 AM, Florian Lindner mailingli...@xgm.de wrote:
Hey,
I've modified my code that it counts the total number of non-zeros (trivial
to put in the preallocation code) and decides upon that wheather to create a
MATSBAIJ or MATDENSE matrix.
Using sparse matrices
Florian Lindner mailingli...@xgm.de writes:
I'm more or less aware of that, but I'm surprised that the performance is
such poor.
If you've ever written a naive triply-nested loop dgemm, you'd know that
it gives up orders of magnitude.
I changed the format of matrixC to dense now, but the
Am Dienstag, 4. November 2014, 19:14:58 schrieb Jed Brown:
Barry Smith bsm...@mcs.anl.gov writes:
I've tried to use a direct solver like suggested on pp 72, but:
./petBench 600 1 -ksp_type preonly -pc_type lu
You cannot use LU with SBAIJ format. Only Cholesky. So use -pc_type
Am Dienstag, 4. November 2014, 10:08:27 schrieb Barry Smith:
There are a lot of questions here.
Yes, thanks for replying!
On Nov 4, 2014, at 328 AM, Florian Lindner mailingli...@xgm.de wrote:
Hello,
I have a fulll matrix of size e.g. 603x603 of which I'm very disappointed
So you have a dense, very ill-conditioned matrix. Seems to me you should just
be using the dense LU/Cholesky factorization unless you know how to
preconditioner these types of matrices.
http://scicomp.stackexchange.com/questions/7561/do-rbf-kernel-matrices-tend-to-be-ill-conditioned
You
Hello,
I have a fulll matrix of size e.g. 603x603 of which I'm very disappointed with
the runtime, compared to a naive LU / forward / backward solution. My petsc
solution takes about 14s, while the old one takes just 0.5s. (when you're
looking at sparse matrices the figures are almost
There are a lot of questions here.
On Nov 4, 2014, at 3:28 AM, Florian Lindner mailingli...@xgm.de wrote:
Hello,
I have a fulll matrix of size e.g. 603x603 of which I'm very disappointed
with the runtime, compared to a naive LU / forward / backward solution. My
petsc solution
Barry Smith bsm...@mcs.anl.gov writes:
I've tried to use a direct solver like suggested on pp 72, but:
./petBench 600 1 -ksp_type preonly -pc_type lu
You cannot use LU with SBAIJ format. Only Cholesky. So use -pc_type cholesky
And using a sparse matrix format for a dense matrix is a
