1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML3.2 EN">
<HTML>
<HEAD> <link rel="canonical" href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/TS/TSAlphaSetParams.html" />
<META NAME="GENERATOR" CONTENT="DOCTEXT">
<TITLE>TSAlphaSetParams</TITLE>
</HEAD>
<BODY BGCOLOR="FFFFFF">
<div id="version" align=right><b>petsc-3.4.2 2013-07-02</b></div>
<A NAME="TSAlphaSetParams"><H1>TSAlphaSetParams</H1></A>
sets the algorithmic parameters for <A HREF="../TS/TSALPHA.html#TSALPHA">TSALPHA</A>
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscts.h"
PetscErrorCode TSAlphaSetParams(TS ts,PetscReal alpha_m,PetscReal alpha_f,PetscReal gamma)
</PRE>
Not Collective
<P>
<H3><FONT COLOR="#CC3333">Second-order accuracy can be obtained so long as</FONT></H3>
\gamma = 0.5 + alpha_m - alpha_f
<P>
<H3><FONT COLOR="#CC3333">Unconditional stability requires</FONT></H3>
\alpha_m >= \alpha_f >= 0.5
<P>
<H3><FONT COLOR="#CC3333">Backward Euler method is recovered when</FONT></H3>
\alpha_m = \alpha_f = gamma = 1
<P>
<P>
<H3><FONT COLOR="#CC3333">Input Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ts </B></TD><TD>- timestepping context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>\alpha_m </B></TD><TD>- algorithmic paramenter
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>\alpha_f </B></TD><TD>- algorithmic paramenter
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>\gamma </B></TD><TD>- algorithmic paramenter
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Options Database</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-ts_alpha_alpha_m <alpha_m></B></TD><TD>- . -ts_alpha_alpha_f <alpha_f>
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-ts_alpha_gamma <gamma></B></TD><TD>-
Note:
Use of this function is normally only required to hack <A HREF="../TS/TSALPHA.html#TSALPHA">TSALPHA</A> to
use a modified integration scheme. Users should call
<A HREF="../TS/TSAlphaSetRadius.html#TSAlphaSetRadius">TSAlphaSetRadius</A>() to set the desired spectral radius of the methods
(i.e. high-frequency damping) in order so select optimal values for
these parameters.
</TD></TR></TABLE>
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../TS/TSAlphaSetRadius.html#TSAlphaSetRadius">TSAlphaSetRadius</A>(), <A HREF="../TS/TSAlphaGetParams.html#TSAlphaGetParams">TSAlphaGetParams</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>advanced
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/ts/impls/implicit/alpha/alpha.c.html#TSAlphaSetParams">src/ts/impls/implicit/alpha/alpha.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>
</BODY></HTML>
|
