[CIG-SHORT] [EXTERNAL] Re: Pylith stuck in the final step "Formulation finalize."

[Brad Aagaard]

On 10/02/2018 02:49 AM, Matthew Knepley wrote:
> On Tue, Oct 2, 2018 at 3:01 AM <hkj at mail.ustc.edu.cn 
> <mailto:hkj at mail.ustc.edu.cn>> wrote:
> 
> 
>     Thank you for nice advice, I already used hdf5 output before, but
>     turning off the volume output do help a lot!
> 
>     There are still two things bothering me:
> 
>     1. Since I only need two time points: 30yr's and 40yr's output among
>     the whole 40 yr's simulation, but the minimum time step is 0.01 yr.
>     Except changing material properties, can pylith only simulate the
>     model for  dt = 0.01 yr in the first few years, and than gradually
>     get larger in the remaining time period?
> 
> 
> Yes, you are in control of the timestep. You can use
> 
> [pylithapp.problem.formulation]
> solver = pylith.problems.SolverNonlinear
> time_step = pylith.problems.TimeStepAdapt
> 
> or TimeStepUser.

TimeStepAdapt for a linear Maxwell model will result in a uniform time 
step equal to 1/10 of the Maxwell time. For a powerlaw rheology it will 
result in a time step equal to 1/10 of the current Maxwell time.

TimeStepUser will do whatever you prescribe it to do.

> 
>     2. Is it possible make material properties change with time during
>     the simulation?(For example, let viscosity to be 1.0e+20 during 0~10
>     year and to be 1.0e+21 during 10~20 year)
> 
> 
> Brad and Charles will know how to do this. However, does this make 
> physical sense?

The generalized Maxwell rheology or powerlaw rheology may be of interest 
to you. As Matt said, be sure what you are trying to do makes physical 
sense.

Regards,
Brad