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<TITLE>DMDAVecGetArrayRead</TITLE>
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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
<div id="bugreport" align=right><a href="mailto:petsc-maint@mcs.anl.gov?subject=Typo or Error in Documentation &body=Please describe the typo or error in the documentation: petsc-3.14.5 v3.14.5 docs/manualpages/DMDA/DMDAVecGetArrayRead.html "><small>Report Typos and Errors</small></a></div>
<A NAME="DMDAVecGetArrayRead"><H1>DMDAVecGetArrayRead</H1></A>
Returns a multiple dimension array that shares data with the underlying vector and is indexed using the global dimensions.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscdmda.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../DMDA/DMDAVecGetArrayRead.html#DMDAVecGetArrayRead">DMDAVecGetArrayRead</A>(<A HREF="../DM/DM.html#DM">DM</A> da,<A HREF="../Vec/Vec.html#Vec">Vec</A> vec,void *array)
</PRE>
Not collective
<P>
<H3><FONT COLOR="#CC3333">Input Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>da </B></TD><TD>- the distributed array
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>vec </B></TD><TD>- the vector, either a vector the same size as one obtained with <A HREF="../DM/DMCreateGlobalVector.html#DMCreateGlobalVector">DMCreateGlobalVector</A>() or <A HREF="../DM/DMCreateLocalVector.html#DMCreateLocalVector">DMCreateLocalVector</A>()
</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>array </B></TD><TD>- the array
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
Call <A HREF="../DMDA/DMDAVecRestoreArrayRead.html#DMDAVecRestoreArrayRead">DMDAVecRestoreArrayRead</A>() once you have finished accessing the vector entries.
<P>
In C, the indexing is "backwards" from what expects: array[k][j][i] NOT array[i][j][k]!
<P>
If vec is a local vector (obtained with <A HREF="../DM/DMCreateLocalVector.html#DMCreateLocalVector">DMCreateLocalVector</A>() etc) then the ghost point locations are accessible. If it is
a global vector then the ghost points are not accessible. Of course with the local vector you will have had to do the
<P>
appropriate <A HREF="../DM/DMGlobalToLocalBegin.html#DMGlobalToLocalBegin">DMGlobalToLocalBegin</A>() and <A HREF="../DM/DMGlobalToLocalEnd.html#DMGlobalToLocalEnd">DMGlobalToLocalEnd</A>() to have correct values in the ghost locations.
<P>
<H3><FONT COLOR="#CC3333">Fortran Notes</FONT></H3>
From Fortran use DMDAVecGetArrayReadF90() and pass for the array type <A HREF="../Sys/PetscScalar.html#PetscScalar">PetscScalar</A>,pointer :: array(:,...,:) of the appropriate
dimension. For a <A HREF="../DMDA/DMDA.html#DMDA">DMDA</A> created with a dof of 1 use the dimension of the <A HREF="../DMDA/DMDA.html#DMDA">DMDA</A>, for a <A HREF="../DMDA/DMDA.html#DMDA">DMDA</A> created with a dof greater than 1 use one more than the
dimension of the <A HREF="../DMDA/DMDA.html#DMDA">DMDA</A>. The order of the indices is array(xs:xs+xm-1,ys:ys+ym-1,zs:zs+zm-1) (when dof is 1) otherwise
array(0:dof-1,xs:xs+xm-1,ys:ys+ym-1,zs:zs+zm-1) where the values are obtained from
<A HREF="../DMDA/DMDAGetCorners.html#DMDAGetCorners">DMDAGetCorners</A>() for a global array or <A HREF="../DMDA/DMDAGetGhostCorners.html#DMDAGetGhostCorners">DMDAGetGhostCorners</A>() for a local array. Include petsc/finclude/petscdmda.h90 to access this routine.
<P>
Due to bugs in the compiler DMDAVecGetArrayReadF90() does not work with gfortran versions before 4.5
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../DMDA/DMDAGetGhostCorners.html#DMDAGetGhostCorners">DMDAGetGhostCorners</A>(), <A HREF="../DMDA/DMDAGetCorners.html#DMDAGetCorners">DMDAGetCorners</A>(), <A HREF="../Vec/VecGetArray.html#VecGetArray">VecGetArray</A>(), <A HREF="../Vec/VecRestoreArray.html#VecRestoreArray">VecRestoreArray</A>(), <A HREF="../DMDA/DMDAVecRestoreArrayRead.html#DMDAVecRestoreArrayRead">DMDAVecRestoreArrayRead</A>(), <A HREF="../DMDA/DMDAVecRestoreArrayDOF.html#DMDAVecRestoreArrayDOF">DMDAVecRestoreArrayDOF</A>()
<BR><A HREF="../DMDA/DMDAVecGetArrayDOF.html#DMDAVecGetArrayDOF">DMDAVecGetArrayDOF</A>(), <A HREF="../DMDA/DMDAVecGetArray.html#DMDAVecGetArray">DMDAVecGetArray</A>(), <A HREF="../DMDA/DMDAVecRestoreArray.html#DMDAVecRestoreArray">DMDAVecRestoreArray</A>(), <A HREF="../DMDA/DMDAVecGetArrayRead.html#DMDAVecGetArrayRead">DMDAVecGetArrayRead</A>(), <A HREF="../DMDA/DMDAVecRestoreArrayRead.html#DMDAVecRestoreArrayRead">DMDAVecRestoreArrayRead</A>(),
<A HREF="../DMSTAG/DMStagVecGetArrayRead.html#DMStagVecGetArrayRead">DMStagVecGetArrayRead</A>()
<P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>intermediate<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/dm/impls/da/dagetarray.c.html#DMDAVecGetArrayRead">src/dm/impls/da/dagetarray.c</A>
<P><H3><FONT COLOR="#CC3333">Examples</FONT></H3>
<A HREF="../../../src/dm/tutorials/ex3.c.html">src/dm/tutorials/ex3.c.html</A><BR>
<A HREF="../../../src/ksp/ksp/tutorials/ex43.c.html">src/ksp/ksp/tutorials/ex43.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex3.c.html">src/snes/tutorials/ex3.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex14.c.html">src/snes/tutorials/ex14.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex15.c.html">src/snes/tutorials/ex15.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex19.c.html">src/snes/tutorials/ex19.c.html</A><BR>
<A HREF="../../../src/snes/tutorials/ex78.c.html">src/snes/tutorials/ex78.c.html</A><BR>
<A HREF="../../../src/ts/tutorials/ex7.c.html">src/ts/tutorials/ex7.c.html</A><BR>
<A HREF="../../../src/ts/tutorials/ex9.c.html">src/ts/tutorials/ex9.c.html</A><BR>
<A HREF="../../../src/ts/tutorials/ex10.c.html">src/ts/tutorials/ex10.c.html</A><BR>
<A HREF="../../../src/ts/tutorials/ex13.c.html">src/ts/tutorials/ex13.c.html</A><BR>
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