<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta http-equiv="content-type"
content="text/html; charset=utf-8"></head><body><div dir="ltr"><p><span style="color: rgb(0, 0, 0);">
Hello,</span></p><p> </p><p> </p><p><span style="color: rgb(0, 0, 0);">I
intend to compute a parallel Matrix-Vector-Product (via MPI) and
therefore would like to scatter the entries of the input MPI-Vec v
to
a local vector containing all entries relevant to the current
process. </span></p><p> </p><p><span style="color: rgb(0, 0, 0);">To
achieve this I tried defining
a VecScatter, which
scatters
from v
to a sequential Vec
v_seq (each process has it's own version of v_seq). However,
storing v_seq (which has one
entry for each global row, thus
containing a large amount of
zero-entries)
may demand too
much storage space (in
comparison to my data-sparse Matrix-Storage-Format).</span></p><p> </p><p><span style="color: rgb(0, 0,
0);">I
am interested in possibilities to scatter v to a sparse Vec-type
to avoid storing unnecessary large
amounts of
zero-entries. Is there a sparse Vector format in Petsc
compatible to
the VecScatter procedure
or is there another efficient way to compute
Matrix-Vector-Products
without usinglarge amounts
of storage space on each process?
</span></p><p> </p><p> </p><p><span style="color: rgb(0, 0, 0);">Best
Regards</span></p><p><span style="color: rgb(0, 0, 0);"> Hannes
Brandt</span></p><p><span style="color: rgb(0, 0, 0);"></span></p></div></body></html>