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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="MatFDColoringSetParameters"><H1>MatFDColoringSetParameters</H1></A>
Sets the parameters for the sparse approximation of a Jacobian matrix using finite differences.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../MatFD/MatFDColoringSetParameters.html#MatFDColoringSetParameters">MatFDColoringSetParameters</A>(<A HREF="../Mat/MatFDColoring.html#MatFDColoring">MatFDColoring</A> matfd,<A HREF="../Sys/PetscReal.html#PetscReal">PetscReal</A> error,<A HREF="../Sys/PetscReal.html#PetscReal">PetscReal</A> umin)
</PRE>
Logically Collective on <A HREF="../Mat/MatFDColoring.html#MatFDColoring">MatFDColoring</A>
<P>
The Jacobian is estimated with the differencing approximation
<PRE>
F'(u)_{:,i} = [F(u+h*dx_{i}) - F(u)]/h where
htype = 'ds':
h = error_rel*u[i] if abs(u[i]) > umin
= +/- error_rel*umin otherwise, with +/- determined by the sign of u[i]
dx_{i} = (0, ... 1, .... 0)
htype = 'wp':
h = error_rel * sqrt(1 + ||u||)
</PRE>
<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>coloring </B></TD><TD>- the coloring context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>error_rel </B></TD><TD>- relative error
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>umin </B></TD><TD>- minimum allowable u-value magnitude
</TD></TR></TABLE>
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../MatFD/MatFDColoringCreate.html#MatFDColoringCreate">MatFDColoringCreate</A>(), <A HREF="../MatFD/MatFDColoringSetFromOptions.html#MatFDColoringSetFromOptions">MatFDColoringSetFromOptions</A>()
<BR>
<P>
<P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>advanced<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/mat/matfd/fdmatrix.c.html#MatFDColoringSetParameters">src/mat/matfd/fdmatrix.c</A>
<BR><A HREF="./index.html">Index of all MatFD routines</A>
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