petsc-3.14.5 2021-03-03
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# MatMPIBAIJSetPreallocationCSR

Creates a sparse parallel matrix in BAIJ format using the given nonzero structure and (optional) numerical values

### Synopsis

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

Collective

### Input Parameters

| B | - the matrix
| bs | - the block size
| i | - the indices into j for the start of each local row (starts with zero)
| j | - the column indices for each local row (starts with zero) these must be sorted for each row
| v | - optional values in the matrix

### Notes

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=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=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

MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIBAIJSetPreallocation(), MatCreateAIJ(), MPIAIJ, MatCreateMPIBAIJWithArrays(), MPIBAIJ

### Level

advanced

### Location

src/mat/impls/baij/mpi/mpibaij.c

### Implementations

MatMPIBAIJSetPreallocationCSR_MPIBAIJ in src/mat/impls/baij/mpi/mpibaij.c
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