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<div id="version" align=right><b>slepc-3.23.1 2025-05-01</b></div>
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<H1>EPSGetLeftEigenvector</H1>
Gets the i-th left eigenvector as computed by <A HREF="../EPS/EPSSolve.html#EPSSolve">EPSSolve</A>().
<H3><FONT COLOR="#883300">Synopsis</FONT></H3>
<PRE>
#include "slepceps.h"
<A HREF="https://petsc.org/release/manualpages/Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../EPS/EPSGetLeftEigenvector.html#EPSGetLeftEigenvector">EPSGetLeftEigenvector</A>(<A HREF="../EPS/EPS.html#EPS">EPS</A> eps,<A HREF="https://petsc.org/release/manualpages/Sys/PetscInt.html#PetscInt">PetscInt</A> i,<A HREF="https://petsc.org/release/manualpages/Vec/Vec.html#Vec">Vec</A> Wr,<A HREF="https://petsc.org/release/manualpages/Vec/Vec.html#Vec">Vec</A> Wi)
</PRE>
Collective
<P>
<H3><FONT COLOR="#883300">Input Parameters</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>eps </B></TD><TD> - eigensolver context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>i </B></TD><TD> - index of the solution
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#883300">Output Parameters</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Wr </B></TD><TD> - real part of left eigenvector
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Wi </B></TD><TD> - imaginary part of left eigenvector
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#883300">Notes</FONT></H3>
The caller must provide valid <A HREF="https://petsc.org/release/manualpages/Vec/Vec.html#Vec">Vec</A> objects, i.e., they must be created
by the calling program with e.g. <A HREF="https://petsc.org/release/manualpages/Mat/MatCreateVecs.html#MatCreateVecs">MatCreateVecs</A>().
<P>
If the corresponding eigenvalue is real, then Wi is set to zero. If PETSc is
configured with complex scalars the eigenvector is stored directly in Wr
(Wi is set to zero). In any case, the user can pass NULL in Wr or Wi if
one of them is not required.
<P>
The index i should be a value between 0 and nconv-1 (see <A HREF="../EPS/EPSGetConverged.html#EPSGetConverged">EPSGetConverged</A>()).
Eigensolutions are indexed according to the ordering criterion established
with <A HREF="../EPS/EPSSetWhichEigenpairs.html#EPSSetWhichEigenpairs">EPSSetWhichEigenpairs</A>().
<P>
Left eigenvectors are available only if the twosided flag was set, see
<A HREF="../EPS/EPSSetTwoSided.html#EPSSetTwoSided">EPSSetTwoSided</A>().
<P>
<P>
<H3><FONT COLOR="#883300">See Also</FONT></H3>
<A HREF="../EPS/EPSGetEigenvector.html#EPSGetEigenvector">EPSGetEigenvector</A>(), <A HREF="../EPS/EPSGetConverged.html#EPSGetConverged">EPSGetConverged</A>(), <A HREF="../EPS/EPSSetWhichEigenpairs.html#EPSSetWhichEigenpairs">EPSSetWhichEigenpairs</A>(), <A HREF="../EPS/EPSSetTwoSided.html#EPSSetTwoSided">EPSSetTwoSided</A>()
<BR><P><B></B><H3><FONT COLOR="#883300">Level</FONT></H3>intermediate<BR>
<H3><FONT COLOR="#883300">Location</FONT></H3>
</B><A HREF="../../../src/eps/interface/epssolve.c.html#EPSGetLeftEigenvector">src/eps/interface/epssolve.c</A>
<P><H3><FONT COLOR="#883300">Examples</FONT></H3>
<A HREF="../../../src/eps/tutorials/ex41.c.html">src/eps/tutorials/ex41.c</A><BR>
<A HREF="../../../src/eps/tutorials/ex55.c.html">src/eps/tutorials/ex55.c</A><BR>
<BR><BR><A HREF="./index.html">Index of all EPS routines</A>
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<BR><A HREF="../singleindex.html">Index of all manual pages</A>
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