[petsc-users] Conditional Constraints

[Shri]

----- Original Message -----



On Sun, Jul 31, 2011 at 22:11, Vijay S. Mahadevan < vijay.m at gmail.com > wrote: 



I saw from the documentation that the GL methods were capable of 
handling DAE systems. But the intention of my question was about the 
usage of the newton solver with functional constraints (with VI) for a 
DAE since in a sense, the DAE systems are a composite of an ODE and a 
constraint. So I was curious whether we could use temporal methods 
that were not intended for DAEs but for stiff ODEs only and use the VI 
solver to augment/restrict the solution with constraints. The reason 
for this is due to the fact that in the creation of a stiff solver, 
there are additional coefficient constraints that need to be satisfied 
to be used for a DAE but this is less restrictive for solving ODEs. 

Do you want equality or inequality constraints? Equality constraints are naturally handled by writing a DAE. Inequality constraints would be handled by VI. VI is not currently available through TS, but my understanding is that Shri is looking into this and it will eventually be available there too. 

I have already added TSVISetVariableBounds() by which lower and upper bounds can be set for variables directly through the TS interface. I am currently working on getting an example ready for TS with VI solver. Hopefully, i will add it by this week. 


Thanks, 
Shri 

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