STSetMatStructure#
Sets an internal MatStructure attribute to indicate which is the relation of the sparsity pattern of all ST matrices.
Synopsis#
#include "slepcst.h"
PetscErrorCode STSetMatStructure(ST st,MatStructure str)
Logically Collective
Input Parameters#
st - the spectral transformation context
str - either
SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SUBSET_NONZERO_PATTERN, orUNKNOWN_NONZERO_PATTERN
Options Database Key#
-st_matstructure
- the structure flag, one ofsame,different,subset,unknown.
Notes#
If the sparsity pattern of the second matrix is equal or a subset of the
pattern of the first matrix then it is recommended to set this attribute
for efficiency reasons (in particular, for internal MatAXPY() operations).
If not set, the default is UNKNOWN_NONZERO_PATTERN, in which case the patterns
will be compared to determine if they are equal.
This function has no effect in the case of standard eigenproblems.
In case of polynomial eigenproblems, the flag applies to all matrices relative to the first one.
See Also#
Level#
advanced
Location#
src/sys/classes/st/interface/stset.c
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