setting for rimp2 caculation with ricc2

[YangSiYa]

Dear Sir

   I have 14 separate machines with  4-CPU  and 8 GB memory in each machine , these nodes connected to each other.When parallel RI-MP2 calculation with ricc2 is executed, how should I set up processor and memory the caculation coulld be achived best.
   I would be grateful for any help to resolve this issue.
 

[christof.haettig]

Well, this depends on the size of your systems and on your priorities: is it more important for you to get a few calculations done very fast or is it more important to
get a lot of calculations done as soon as possible. Parallelization will help you only in the first case and if you problem size is large enough. Also the number of nodes that the program can use efficiently depends on the system size (number of correlated electrons and basis set size).

Best regards,
C.H.

[YangSiYa]

My system now is operating 50 atoms,the calculation method is rimp2/TZVPP and the process is 4.
How can I set my computer's memory and disk size?Or is there any other way to make my cluster operate normally?

In addition,I am confronted with these problems in job.1:

 upper limit for coordinate changes =   0.3000
 interpolation/extrapolation has been enabled
 display optimization statistics for the last   5 cycles

 ------------------------------------------------------------------------------

     relaxation of NUCLEAR COORDINATES in cartesian space

 ------------------------------------------------------------------------------

 reading data block $coord from file <coord>


 <getgrd> : data group $grad  is missing


 cannot find any information which may be used to optimize geometry ...


 MODTRACE: no modules on stack

  so long GRANAT !
 relax ended abnormally
relax step ended abnormally
next step = relax
"job.1" 191L, 4831C       

Then, the system warns " GEO_OPT_FAILED ".

Can you help me?

Thanks for you.

[christof.haettig]

concerning the memory settings for ricc2: it should be set to something between 60 and 80 percent of the available physical RAM. This hold for sequential and parallel calculations.

Concerning your problem with the geometry optimization: The message tells you that the geometry relaxation code was called without that any gradients have been calculated before. Either, you gradient calculation failed, or you had some remainings from a previous job in you control file...