[Pw_forum] insufficient virtual memory for a Zn48O48 system!!!!!!!!

[Shujun Hu]

Dear Drs,
I try to do the calculation for a 96-atom system, Zn48O48 (before doping, for the
purpose of comparing). There are totle 864 electrons, 12 for Zn and 6 for O
respectively. And the number of bands is set to be 450. After running the memory.x
system gave such information:
**********************************************************
     Program memory    v.2.1.2  starts ...
     Today is 28Feb2005 at 15:49:49
     Estimated Max memory (k-point code): 14690.79Mb
     nonscalable memory =  123.65Mb
        scalable memory = 3654.75Mb
     nonscalable wspace =  148.32Mb
        scalable wspace =10764.07Mb   (diag:10764.07Mb, mix:  287.04Mb)
     Estimates based on 16-byte complex,  8-byte reals,  4-byte integers
**********************************************************
As my pc taking only 512M physical momory, I selected "conjugate-gradient
diagonalization" mode. Then i run memory.x again:
**********************************************************
     Program memory    v.2.1.2  starts ...
     Today is 28Feb2005 at 15:54:12
     Estimated Max memory (k-point code):  4048.99Mb
     nonscalable memory =   97.94Mb
        scalable memory = 3654.75Mb
     nonscalable wspace =    9.27Mb
        scalable wspace =  287.04Mb   (diag:   23.92Mb, mix:  287.04Mb)
     Estimates based on 16-byte complex,  8-byte reals,  4-byte integers
**********************************************************
Then i run pw.x programme. Unfortunately such information appeared:
**********************************************************
......
     threshold for starting DIIS:       0.0010
     reduced basis size:     3
forrtl: severe (41): insufficient virtual memory
Image              PC        Routine            Line        Source
pw.x               082622F4  Unknown               Unknown  Unknown
 
Stack trace terminated abnormally.
**********************************************************
Noting that there is insufficient virtual memory (swap partition is working, but
only 2G for Redhat linux), I set up an 5G active swapfile to add to the virtual
memory. But same information appeared as above.
    Maybe such system is too large. I want to know why it cannt work as there is
enough virtual memory. Should i add the physical memory?

    Best wishes

                              Shujun Hu
____________________________
hushujun at mail.sdu.edu.cn