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, or UNKNOWN_NONZERO_PATTERN

Options Database Key#

  • -st_matstructure - Indicates the structure flag, where is one of ‘same’ (matrices have the same nonzero pattern), ‘different’ (different nonzero pattern), ‘subset’ (pattern is a subset of the first one), or ‘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#

STSetMatrices(), MatAXPY()

Level#

advanced

Location#

src/sys/classes/st/interface/stset.c

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