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<H1>SVDSetDimensions</H1>
Sets the number of singular values to compute and the dimension of the subspace.
<H3><FONT COLOR="#883300">Synopsis</FONT></H3>
<PRE>
#include "slepcsvd.h"
<A HREF="https://petsc.org/release/manualpages/Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../SVD/SVDSetDimensions.html#SVDSetDimensions">SVDSetDimensions</A>(<A HREF="../SVD/SVD.html#SVD">SVD</A> svd,<A HREF="https://petsc.org/release/manualpages/Sys/PetscInt.html#PetscInt">PetscInt</A> nsv,<A HREF="https://petsc.org/release/manualpages/Sys/PetscInt.html#PetscInt">PetscInt</A> ncv,<A HREF="https://petsc.org/release/manualpages/Sys/PetscInt.html#PetscInt">PetscInt</A> mpd)
</PRE>
Logically 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>svd </B></TD><TD> - the singular value solver context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>nsv </B></TD><TD> - number of singular values to compute
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ncv </B></TD><TD> - the maximum dimension of the subspace to be used by the solver
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>mpd </B></TD><TD> - the maximum dimension allowed for the projected problem
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#883300">Options Database Keys</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-svd_nsv <nsv> </B></TD><TD> - Sets the number of singular values
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-svd_ncv <ncv> </B></TD><TD> - Sets the dimension of the subspace
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-svd_mpd <mpd> </B></TD><TD> - Sets the maximum projected dimension
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#883300">Notes</FONT></H3>
Use <A HREF="https://petsc.org/release/manualpages/Sys/PETSC_DETERMINE.html#PETSC_DETERMINE">PETSC_DETERMINE</A> for ncv and mpd to assign a reasonably good value, which is
dependent on the solution method and the number of singular values required. For
any of the arguments, use <A HREF="https://petsc.org/release/manualpages/Sys/PETSC_CURRENT.html#PETSC_CURRENT">PETSC_CURRENT</A> to preserve the current value.
<P>
The parameters ncv and mpd are intimately related, so that the user is advised
to set one of them at most. Normal usage is that
(a) in cases where nsv is small, the user sets ncv (a reasonable default is 2*nsv); and
(b) in cases where nsv is large, the user sets mpd.
<P>
The value of ncv should always be between nsv and (nsv+mpd), typically
ncv=nsv+mpd. If nsv is not too large, mpd=nsv is a reasonable choice, otherwise
a smaller value should be used.
<P>
<P>
<H3><FONT COLOR="#883300">See Also</FONT></H3>
<A HREF="../SVD/SVDGetDimensions.html#SVDGetDimensions">SVDGetDimensions</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/svd/interface/svdopts.c.html#SVDSetDimensions">src/svd/interface/svdopts.c</A>
<P><H3><FONT COLOR="#883300">Examples</FONT></H3>
<A HREF="../../../src/svd/tutorials/ex8.c.html">src/svd/tutorials/ex8.c</A><BR>
<A HREF="../../../src/svd/tutorials/ex51.c.html">src/svd/tutorials/ex51.c</A><BR>
<BR><BR><A HREF="./index.html">Index of all SVD routines</A>
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<BR><A HREF="../singleindex.html">Index of all manual pages</A>
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