[petsc-users] correction to previous email

Barry Smith bsmith at petsc.dev
Mon Apr 5 14:18:51 CDT 2021

   That does seem like a great deal of memory per timestep. We need a bit more information to help you. 

    Which TSTrajectory are you using?  Have you built PETSc with --download-revolve?  Are you trying to save the entire trajectory for post-processing or just enough to run with TSAdjoint and do an optimization? The TSTRAJECTORYMEMORY (mis-named) can store some trajectory in memory (which is really what you want) and also some trajectory on disk if needed. Normally with TSAjoint and revolve you don't need to save a huge number of time-steps to files. It sounds like you might be saving all the steps to disk?

    Once we have this information, Hong Zhang who is the expert can provide you with advice on optimizing the use of TSTrajectory.


> On Apr 5, 2021, at 1:30 PM, Zane Charles Jakobs <Zane.Jakobs at colorado.edu> wrote:
> Hi PETSc devs,
> In an email I sent a few minutes ago, I claimed that the TS was writing files of size about 1MB per timestep. That is incorrect; it is actually writing files with a few kB (about 10 kB) per timestep. My questions in the previous email (why are these so big, and can I change that somehow?) still apply though, since this is still much larger than these files "should" be based on the size of the state (128 bits) and the time variable (64 bits).
> My apologies for the error, and thank you for any help you can provide.
> -Zane Jakobs

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