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<div id="version" align=right><b>petsc-3.7.5 2017-01-01</b></div>
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<A NAME="MatCreateSeqSBAIJ"><H1>MatCreateSeqSBAIJ</H1></A>
Creates a sparse symmetric matrix in block AIJ (block compressed row) format. For good matrix assembly performance the user should preallocate the matrix storage by setting the parameter nz (or the array nnz). By setting these parameters accurately, performance during matrix assembly can be increased by more than a factor of 50.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
PetscErrorCode MatCreateSeqSBAIJ(MPI_Comm comm,PetscInt bs,PetscInt m,PetscInt n,PetscInt nz,const PetscInt nnz[],Mat *A)
</PRE>
Collective on <A HREF="../Sys/MPI_Comm.html#MPI_Comm">MPI_Comm</A>
<P>
<H3><FONT COLOR="#CC3333">Input Parameters</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>comm </B></TD><TD>- MPI communicator, set to <A HREF="../Sys/PETSC_COMM_SELF.html#PETSC_COMM_SELF">PETSC_COMM_SELF</A>
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>bs </B></TD><TD>- size of block, the blocks are ALWAYS square. One can use <A HREF="../Mat/MatSetBlockSizes.html#MatSetBlockSizes">MatSetBlockSizes</A>() to set a different row and column blocksize but the row
blocksize always defines the size of the blocks. The column blocksize sets the blocksize of the vectors obtained with <A HREF="../Mat/MatCreateVecs.html#MatCreateVecs">MatCreateVecs</A>()
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>m </B></TD><TD>- number of rows, or number of columns
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>nz </B></TD><TD>- number of block nonzeros per block row (same for all rows)
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>nnz </B></TD><TD>- array containing the number of block nonzeros in the upper triangular plus
diagonal portion of each block (possibly different for each block row) or NULL
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<DT><B>A </B> -the symmetric matrix
<br>
<P>
<H3><FONT COLOR="#CC3333">Options Database Keys</FONT></H3>
<DT><B>-mat_no_unroll </B> -uses code that does not unroll the loops in the
block calculations (much slower)
<br>
<DT><B>-mat_block_size </B> -size of the blocks to use
<br>
<P>
<P>
It is recommended that one use the <A HREF="../Mat/MatCreate.html#MatCreate">MatCreate</A>(), <A HREF="../Mat/MatSetType.html#MatSetType">MatSetType</A>() and/or <A HREF="../Mat/MatSetFromOptions.html#MatSetFromOptions">MatSetFromOptions</A>(),
MatXXXXSetPreallocation() paradgm instead of this routine directly.
[MatXXXXSetPreallocation() is, for example, <A HREF="../Mat/MatSeqAIJSetPreallocation.html#MatSeqAIJSetPreallocation">MatSeqAIJSetPreallocation</A>]
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
The number of rows and columns must be divisible by blocksize.
This matrix type does not support complex Hermitian operation.
<P>
Specify the preallocated storage with either nz or nnz (not both).
Set nz=<A HREF="../Sys/PETSC_DEFAULT.html#PETSC_DEFAULT">PETSC_DEFAULT</A> and nnz=NULL for PETSc to control dynamic memory
allocation. See Users-Manual: ch_mat for details.
<P>
If the nnz parameter is given then the nz parameter is ignored
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Mat/MatCreate.html#MatCreate">MatCreate</A>(), <A HREF="../Mat/MatCreateSeqAIJ.html#MatCreateSeqAIJ">MatCreateSeqAIJ</A>(), <A HREF="../Mat/MatSetValues.html#MatSetValues">MatSetValues</A>(), <A HREF="../Mat/MatCreateSBAIJ.html#MatCreateSBAIJ">MatCreateSBAIJ</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>intermediate
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/mat/impls/sbaij/seq/sbaij.c.html#MatCreateSeqSBAIJ">src/mat/impls/sbaij/seq/sbaij.c</A>
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