MatSeqBAIJSetPreallocationCSR — PETSc 3.25.1 documentation

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# MatSeqBAIJSetPreallocationCSR

Creates a sparse sequential matrix in `MATSEQBAIJ` format using the given nonzero structure and (optional) numerical values

## Synopsis

    #include "petscmat.h"
    PetscErrorCode MatSeqBAIJSetPreallocationCSR(Mat B, PetscInt bs, const PetscInt i[], const PetscInt j[], const PetscScalar v[])

Collective

## Input Parameters

- B - the matrix

- bs - the blocksize

- i - the indices into `j` for the start of each local row (indices start with zero)

- j - the column indices for each local row (indices start with zero) these must be sorted for each row

- v - optional values in the matrix, use `NULL` if not provided

## Notes

The `i`,`j`,`v` values are COPIED with this routine; to avoid the copy use `MatCreateSeqBAIJWithArrays()`

The order of the entries in values is specified by the `MatOption` `MAT_ROW_ORIENTED`. For example, C programs may want to use the default `MAT_ROW_ORIENTED` of `PETSC_TRUE` and use an array v[nnz][bs][bs] where the second index is over rows within a block and the last index is over columns within a block row. Fortran programs will likely set `MAT_ROW_ORIENTED` of `PETSC_FALSE` and use a Fortran array v(bs,bs,nnz) in which the first index is over rows within a block column and the second index is over columns within a block.

Though this routine has Preallocation() in the name it also sets the exact nonzero locations of the matrix entries and usually the numerical values as well

## See Also

Matrices, `Mat`, `MatCreate()`, `MatCreateSeqBAIJ()`, `MatSetValues()`, `MatSeqBAIJSetPreallocation()`, `MATSEQBAIJ`

## Level

advanced

## Location

src/mat/impls/baij/seq/baij.c

## Implementations

MatSeqBAIJSetPreallocationCSR_SeqBAIJ() in src/mat/impls/baij/seq/baij.c

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Index of all manual pages