petsc-3.12.5 2020-03-29

TSSetI2Function

Set the function to compute F(t,U,U_t,U_tt) where F = 0 is the DAE to be solved.

#include "petscts.h"  
PetscErrorCode TSSetI2Function(TS ts,Vec F,TSI2Function fun,void *ctx)

Logically Collective on TS

	ts	- the TS context obtained from TSCreate()
	F	- vector to hold the residual (or NULL to have it created internally)
	fun	- the function evaluation routine
	ctx	- user-defined context for private data for the function evaluation routine (may be NULL)

    PetscErrorCode fun(TS ts,PetscReal t,Vec U,Vec U_t,Vec U_tt,Vec F,ctx);

	t	- time at step/stage being solved
	U	- state vector
	U_t	- time derivative of state vector
	U_tt	- second time derivative of state vector
	F	- function vector
	ctx	- [optional] user-defined context for matrix evaluation routine (may be NULL)

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