MatSeqBDiagSetPreallocation

Sets the nonzero structure and (optionally) arrays.

int MatSeqBDiagSetPreallocation(Mat B,int nd,int bs,int *diag,PetscScalar **diagv)

Collective on MPI_Comm

    diag = i/bs - j/bs  (integer division)

Set diag=PETSC_NULL on input for PETSc to dynamically allocate memory as needed (expensive).

	B	- the matrix
	nd	- number of block diagonals (optional)
	bs	- each element of a diagonal is an bs x bs dense matrix
	diag	- optional array of block diagonal numbers (length nd). For a matrix element A[i,j], where i=row and j=column, the diagonal number is
	diagv	- pointer to actual diagonals (in same order as diag array), if allocated by user. Otherwise, set diagv=PETSC_NULL on input for PETSc to control memory allocation.

-mat_block_size <bs> -Sets blocksize

-mat_bdiag_diags <s1,s2,s3,...> -Sets diagonal numbers

See the users manual for further details regarding this storage format.

Fortran programmers cannot set diagv; this value is ignored.

matrix, block, diagonal, sparse