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<div id="version" align=right><b>petsc-3.4.2 2013-07-02</b></div>
<A NAME="TSSetIJacobian"><H1>TSSetIJacobian</H1></A>
Set the function to compute the matrix dF/dU + a*dF/dU_t where F(t,U,U_t) is the function you provided with <A HREF="../TS/TSSetIFunction.html#TSSetIFunction">TSSetIFunction</A>().
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscts.h"
PetscErrorCode TSSetIJacobian(TS ts,Mat Amat,Mat Pmat,TSIJacobian f,void *ctx)
</PRE>
Logically Collective on <A HREF="../TS/TS.html#TS">TS</A>
<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>ts </B></TD><TD>- the <A HREF="../TS/TS.html#TS">TS</A> context obtained from <A HREF="../TS/TSCreate.html#TSCreate">TSCreate</A>()
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Amat </B></TD><TD>- (approximate) Jacobian matrix
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Pmat </B></TD><TD>- matrix used to compute preconditioner (usually the same as Amat)
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>f </B></TD><TD>- the Jacobian evaluation routine
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ctx </B></TD><TD>- user-defined context for private data for the Jacobian evaluation routine (may be NULL)
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Calling sequence of f</FONT></H3>
<pre>
f(<A HREF="../TS/TS.html#TS">TS</A> ts,<A HREF="../Sys/PetscReal.html#PetscReal">PetscReal</A> t,<A HREF="../Vec/Vec.html#Vec">Vec</A> U,<A HREF="../Vec/Vec.html#Vec">Vec</A> U_t,<A HREF="../Sys/PetscReal.html#PetscReal">PetscReal</A> a,<A HREF="../Mat/Mat.html#Mat">Mat</A> *Amat,<A HREF="../Mat/Mat.html#Mat">Mat</A> *Pmat,<A HREF="../Mat/MatStructure.html#MatStructure">MatStructure</A> *flag,void *ctx);
</pre>
<P>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>t </B></TD><TD>- time at step/stage being solved
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>U </B></TD><TD>- state vector
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>U_t </B></TD><TD>- time derivative of state vector
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>a </B></TD><TD>- shift
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Amat </B></TD><TD>- (approximate) Jacobian of F(t,U,W+a*U), equivalent to dF/dU + a*dF/dU_t
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Pmat </B></TD><TD>- matrix used for constructing preconditioner, usually the same as Amat
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>flag </B></TD><TD>- flag indicating information about the preconditioner matrix
structure (same as flag in <A HREF="../KSP/KSPSetOperators.html#KSPSetOperators">KSPSetOperators</A>())
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ctx </B></TD><TD>- [optional] user-defined context for matrix evaluation routine
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
The matrices Amat and Pmat are exactly the matrices that are used by <A HREF="../SNES/SNES.html#SNES">SNES</A> for the nonlinear solve.
<P>
The matrix dF/dU + a*dF/dU_t you provide turns out to be
the Jacobian of F(t,U,W+a*U) where F(t,U,U_t) = 0 is the DAE to be solved.
The time integrator internally approximates U_t by W+a*U where the positive "shift"
a and vector W depend on the integration method, step size, and past states. For example with
the backward Euler method a = 1/dt and W = -a*U(previous timestep) so
W + a*U = a*(U - U(previous timestep)) = (U - U(previous timestep))/dt
<P>
<P>
<H3><FONT COLOR="#CC3333">Keywords</FONT></H3>
<A HREF="../TS/TS.html#TS">TS</A>, timestep, DAE, Jacobian
<BR>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../TS/TSSetIFunction.html#TSSetIFunction">TSSetIFunction</A>(), <A HREF="../TS/TSSetRHSJacobian.html#TSSetRHSJacobian">TSSetRHSJacobian</A>(), <A HREF="../SNES/SNESComputeJacobianDefaultColor.html#SNESComputeJacobianDefaultColor">SNESComputeJacobianDefaultColor</A>(), <A HREF="../SNES/SNESComputeJacobianDefault.html#SNESComputeJacobianDefault">SNESComputeJacobianDefault</A>()
<BR>
<P>
<P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>beginner
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/ts/interface/ts.c.html#TSSetIJacobian">src/ts/interface/ts.c</A>
<BR><A HREF="./index.html">Index of all TS routines</A>
<BR><A HREF="../../index.html">Table of Contents for all manual pages</A>
<BR><A HREF="../singleindex.html">Index of all manual pages</A>
<P><H3><FONT COLOR="#CC3333">Examples</FONT></H3>
<A HREF="../../../src/ts/examples/tutorials/ex6.c.html">src/ts/examples/tutorials/ex6.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex8.c.html">src/ts/examples/tutorials/ex8.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex9.c.html">src/ts/examples/tutorials/ex9.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex10.c.html">src/ts/examples/tutorials/ex10.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex14.c.html">src/ts/examples/tutorials/ex14.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex15.c.html">src/ts/examples/tutorials/ex15.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex16.c.html">src/ts/examples/tutorials/ex16.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex17.c.html">src/ts/examples/tutorials/ex17.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex22.c.html">src/ts/examples/tutorials/ex22.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex23.c.html">src/ts/examples/tutorials/ex23.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex24.c.html">src/ts/examples/tutorials/ex24.c.html</A><BR>
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