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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
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<A NAME="MatGetValuesLocal"><H1>MatGetValuesLocal</H1></A>
retrieves values from certain locations in a matrix using the local numbering of the indices defined previously by <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>()
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../Mat/MatGetValuesLocal.html#MatGetValuesLocal">MatGetValuesLocal</A>(<A HREF="../Mat/Mat.html#Mat">Mat</A> mat,<A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> nrow,const <A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> irow[],<A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> ncol,const <A HREF="../Sys/PetscInt.html#PetscInt">PetscInt</A> icol[],<A HREF="../Sys/PetscScalar.html#PetscScalar">PetscScalar</A> y[])
</PRE>
Not Collective
<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>mat </B></TD><TD>- the matrix
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>nrow, irow </B></TD><TD>- number of rows and their local indices
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ncol, icol </B></TD><TD>- number of columns and their local indices
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>y </B></TD><TD>- a logically two-dimensional array of values
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
If you create the matrix yourself (that is not with a call to <A HREF="../DM/DMCreateMatrix.html#DMCreateMatrix">DMCreateMatrix</A>()) then you MUST call <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>() before using this routine.
<P>
This routine can only return values that are owned by the requesting MPI rank. That is, for standard matrix formats, rows that, in the global numbering,
are greater than or equal to restart and less than rend where restart and rend are obtainable from <A HREF="../Mat/MatGetOwnershipRange.html#MatGetOwnershipRange">MatGetOwnershipRange</A>(mat,&rstart,&rend). One can
determine if the resulting global row associated with the local row r is owned by the requesting MPI rank by applying the <A HREF="../IS/ISLocalToGlobalMapping.html#ISLocalToGlobalMapping">ISLocalToGlobalMapping</A> set
with <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>().
<P>
<H3><FONT COLOR="#CC3333">Developer Notes</FONT></H3>
This is labelled with C so does not automatically generate Fortran stubs and interfaces
because it requires multiple Fortran interfaces depending on which arguments are scalar or arrays.
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Mat/MatAssemblyBegin.html#MatAssemblyBegin">MatAssemblyBegin</A>(), <A HREF="../Mat/MatAssemblyEnd.html#MatAssemblyEnd">MatAssemblyEnd</A>(), <A HREF="../Mat/MatSetValues.html#MatSetValues">MatSetValues</A>(), <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>(),
<BR><A HREF="../Mat/MatSetValuesLocal.html#MatSetValuesLocal">MatSetValuesLocal</A>(), <A HREF="../Mat/MatGetValues.html#MatGetValues">MatGetValues</A>()
<P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>advanced<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/mat/interface/matrix.c.html#MatGetValuesLocal">src/mat/interface/matrix.c</A>
<BR><A HREF="./index.html">Index of all Mat routines</A>
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