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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML3.2 EN">
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<TITLE>TSSetIJacobian</TITLE>
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<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 A,Mat B,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>A </B></TD><TD>- Jacobian matrix
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>B </B></TD><TD>- preconditioning matrix for A (may be same as A)
</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 <A HREF="../Sys/PETSC_NULL.html#PETSC_NULL">PETSC_NULL</A>)
</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> *A,<A HREF="../Mat/Mat.html#Mat">Mat</A> *B,<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>A </B></TD><TD>- Jacobian of G(U) = 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>B </B></TD><TD>- preconditioning matrix for A, may be same as A
</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 A and B 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 G(U) = 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>()
<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/ex8.c.html">src/ts/examples/tutorials/ex8.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/ex18.c.html">src/ts/examples/tutorials/ex18.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/ex22f.F.html">src/ts/examples/tutorials/ex22f.F.html</A><BR>
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