[petsc-users] Can I use TS routines for operator split formulation

[Shriram Srinivasan]

It isnt an ODE actually. Its the unsteady diffusion equation u_t + div(k 
grad(u)) = f. The matrices A and B represent discretisations of the 
fluxes.  I am using operator splitting to advance the solution in two 
stages in every time step:
First compute u*, then use it to compute u.

Shriram



On 14-06-09 12:28 PM, Barry Smith wrote:
>    What is the ODE you are solving?
>
>     Barr
>
> On Jun 9, 2014, at 11:51 AM, Shriram Srinivasan <shriram at ualberta.ca> wrote:
>
>> Hi,
>> I am working with the (discretised) PDE:
>> (u* - u_prev) + (tau )A u* = f1
>> (u - u*) + (tau)B u = f2
>> Here A and B are constant matrices which have been assembled, u_prev is solution at previous time level, tau is the time step and u is the solution at current time level.
>>
>> It appears to me I cannot rewrite this in a form required by the TS module. So my question(s) are:
>>
>> 1) Am I missing something here, or is there a way to cast this into the framework of TS
>> 2) If there isn’t a way, am I better off doing the time stepping myself ?
>>
>> Thanks,
>> Shriram