Discussion Forum

Hi

I would concetrate on the message

"Failed to find consistent initial values"

if you make a complex model its important to check that your initial values are OK. I often runa "get initial values" that just populates the matrices and check that it got a good starting point. When yuhave many physics this can be trieckier, and one should start one at the time, but then often the consistent initial values come when you mix two ore more, so one must remain critical to analyse if this error also appears for single physics.

Good luck
Ivar

Hi!

Thanks for rapid reply.
I will try it.
I'm COMSOL beginner ^^
I would you like to keep in touch with you.

Thank you so much.

form LEE

Hi,

I have run this model a few month ago and had the same message.

Two things:

Take care to follow the step by step solution closely in the solve section. You might have missed the "store solution" steps.

Second, RAM might be the case even if you have 4GB. Comsol needs approx. 1.2 GB space for this model. And it has to be in a single Ram block and this is often the problem. After startup, only open Comsol and try again.

Good luck,

Martin

Thank you for your reply^^

I checked 'store solution' step & 'after startup .....'
but I have 'same error message'

he can do, she can do, why not me? ^_^

thanks.

chanhee

Just try to reduce the mesh resolution

What type of computer do you have ? If you have a 32-bit machine, which I suspect you do, then the maximum amount of memory that a single application can use (including COMSOL) is ~ 2 GB. It has nothing to do with a COMSOL limitation, this is a limitation of the hardware whether it be Windows, or Linux. The OS can use all 4 GB with multiple applications, but a SINGLE application is limited to ~ 2 GB (2^31= 2GB).

So, if you are using COMSOL on a problem that approaches this limitation, that is your problem. In Linux, you can monitor this using the "top" command. I don't know how to monitor memory usage in Windows. I believe that the Windows version of COMSOL will show the memory usage in the bottom right-hand corner. In v4, the memory usage shows up on all OSs.

If your hardware is a 64-bit processor, COMSOL can use as much memory as you can load into the box. This will make it much easier to solve larger problems, but a direct solver will still quickly use up all your memory; especially in 3D. So, this is why folks use iterative solvers in 3D with COMSOL.

Hi

FO following the interiour of the process (including RAM use) in Windows you have the excellent tools of Mark Russinovich (no bought in by MS), search for sysinternals and procexp (process explorer) on the web

if you are "just" at the limit for your calculation on a windows 32bit PC, I managed to solve my cases by useing the "client - server" approach, I gain approximatively 25 to 30% RAM available for the solver. But now since I have got a 64 bit machine, I tend to forget all tat ;)

Have fun Comoling
Ivar