petsc-3.3-p7 2013-05-11

TSAlphaSetParams

 sets the algorithmic parameters for TSALPHA

Synopsis

#include "petscts.h"   
PetscErrorCode  TSAlphaSetParams(TS ts,PetscReal alpha_m,PetscReal alpha_f,PetscReal gamma)
Not Collective

Second-order accuracy can be obtained so long as

\gamma = 0.5 + alpha_m - alpha_f

Unconditional stability requires

\alpha_m >= \alpha_f >= 0.5

Backward Euler method is recovered when

\alpha_m = \alpha_f = gamma = 1

Input Parameter

ts - timestepping context
\alpha_m - algorithmic paramenter
\alpha_f - algorithmic paramenter
\gamma - algorithmic paramenter

Options Database

-ts_alpha_alpha_m <alpha_m>- . -ts_alpha_alpha_f <alpha_f>
-ts_alpha_gamma <gamma>- Note: Use of this function is normally only required to hack TSALPHA to use a modified integration scheme. Users should call TSAlphaSetRadius() to set the desired spectral radius of the methods (i.e. high-frequency damping) in order so select optimal values for these parameters.

See Also

TSAlphaSetRadius(), TSAlphaGetParams()

Level:advanced
Location:src/ts/impls/implicit/alpha/alpha.c
Index of all TS routines
Table of Contents for all manual pages
Index of all manual pages