[Wien] question about how to continue calculation on a supercomputer with unix system (Stefaan Cottenier)

[Dong Su]

Dear Stefaan:
Thanks for answering my question. I am not sure I understood your answer. If I run "run_lapw -i 1 -NI". then "In this way, every 
iteration is technically independent of what came before, and all info about the previous iterations is used and read from files. " Does it mean that after this iteration, the result will be saved back the files? therefore I may continue to run another iteration? 

regards



Dong


In the last e-mail you said:
"

Other people might have smarter strategies, but one that works is to 
add "-i 1 -NI" to your run_lapw command (= run only 1 iteration and 
reuse the broyden files if there are any). In this way, every 
iteration is technically independent of what came before, and all info 
about the previous iterations is used and read from files. It avoids 
that you have to let your calculation crash due to exceeding the wall 
time limit.

It requires that at the end of your pbs script you set the command to 
submit this very same pbs script again. In this way, iteration after 
iteration is executed, in an endless loop. You have to watch it (once 
per day?) to decide whether convergence is reached and stop it by e.g. 
removing the pbs script. It will then "crash" in a clean way after the 
current iteration.

If you inspect the wall time used after the first iteration (by having 
the dayfile copied within the pbs script, for instance), you can adapt 
the required wall time accordingly. This will ensure you do not ask 
more walltime than you need, and on most systems this means your jobs 
will spend less time in the queue.
"




Dong SU,Ph.D
Dept. Of Physics, Arizona State University
P.O. Box 871504
Tempe, Arizona 85287-1504
Phone: 480-965-6327
Fax: 480-965-7954
E-mail: dong.su at asu.edu