petsc-3.14.6 2021-03-30

TSAlphaSetParams

sets the algorithmic parameters for TSALPHA

Synopsis

#include "petscts.h"   
PetscErrorCode TSAlphaSetParams(TS ts,PetscReal alpha_m,PetscReal alpha_f,PetscReal gamma)

Logically Collective on TS

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 with

\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.

Level

advanced

Location

src/ts/impls/implicit/alpha/alpha1.c

Implementations

TSAlphaSetParams_Alpha in src/ts/impls/implicit/alpha/alpha1.c

Index of all TS routines
Table of Contents for all manual pages
Index of all manual pages