Hi! Please tell me how can I run def-file in cfx-solve with writing res-file after each iteration?

Hi there, just define that you want to backup results (full) every iteration. You can do so in CFX-Pre. By the way, why do you want to do that? You will need much hard disk space if you are using many cells.

Kramer

Because calculation time is about 4 days. And if something happens with power I wouldn't be able to recover results

hi if you write result for each iteration it will take lot of time to finish the simulation. By default it will automatically over writes the old result file with new one. So you can overcome hard disk space problem.

First of all, you need intermediate result in case your job stops abnormally. However, it may not be necessary to save an intermediate result at end of each iteration because it will increase total simulation time. Saving intermediate result will also hurt parallel performance. The more partition you have, the longer saving result will take. The frequency of saving intermediate result depends on how long the running time you can afford to loss. If you don't want to loss more than one- or two-hour running time and solver can complete N iterations in this period, you need to save result every N iterations.

Hi,

As Kramer and Siv said, in Pre (Output Control, Backup Results) you can choose to backup (full) results every N iterations. This will create a file k*N_full.bak when the iteration k*N is completed. By default, when this backup file is created, the last backup file (k-1)*N_full.bak is delected.

Rui

hi all, i just want to confirm wat rui said.if it is goin to delete the the previous bak up file while creating the new one then what if i want to post process the results intermediately.then in tht case wat do i do?.

thanx rajit

When you use the "interval" option previous backup file is deleted after the latest one has been successfully written.

You can post process the previous one until it's deleted I suppose. You can post process the latest one once it is written...??

Neale

You can just choose to keep all backup files (option in cfx-pre, again watch for your hard disk space; for my last simulation the bak-files (full) were aboute 600 MB, 3M Hexas). Just set the backup interval (cfx-pre) to a good compromis between safety, hard disk usage and speed. The writing of the backup-files can take about 15 min on a big simulation, especially when solving parallel.

When you do so, you will be able to analyse all the intermediate steps in your simulation.

Kramer

As long as the backup isn't bigger than 2GB the default operation is to delete the older files. It seems that there's an issue in the code that I had to delete manually my older backup files. My system is a linux 32bit with ext3 filesystem. I had res files up to 3.5GB. Big runs.

DAK

If at all you have space on your drive and if you want NOT TO DELETE old backup files, use expert parameters option in CFX pre and say to the software not to delete the old backup files.

Be careful, you should have space on your drive else, you cannot get the latest results file also

R P

II just want to add to all the pervious.

1- Check your mesh. Bad quality mesh results in difficulty in coverage. It takes more time to reach required residuals.

2- Upgrade the memory. This'll save a lot of time. In my computer, memory upgrade from 1 to 2 GB reduced calculation time from 4-6 days to 10-12 hours!!

3- If you have a parallel license, run the simulation as local parallel on your machine. This also save time.

Ali

According to your item 2) it looks like you've got 4-6 days running the simulation using the virtual memory. Poor hard disc.

I don't think virtual memory affect simulation time. I incresed it but it didn't help.

Ali