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ERROR-NX- allocated Memory

Builder
Builder

Hi

 

I have kind of big model & running a sol 106. After hour stop with error and no so much details. 

It should be related to the memory but not sure how to fix it

, here are some details

Memory 32GB---

I allocate 7.5GB and changed the scratch directory to a big destination 

This was not enough to solve the issue

please see the attached files 

 

Thanks 

19 REPLIES

Re: ERROR-NX- allocated Memory

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Hello!.

The iterative solver failed, better use the DIRECT SPARSE solver, is more robust.

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: ERROR-NX- allocated Memory

Builder
Builder
Hi Blas,
What is the direct sparse solver, please?
Is it the default solver (without ticking the iterative option in the solution)?

my model has 3D solid elements and Surface-Surace glueing, with a huge number of elements and the solution is the nonlinear sol-106
I can see the RAM memory fully occupied while the program is running.
When I reduced the no.of element and the no. of parts in the assembly for checking it worked (iterative solution) but kind of slow as its now 15hrs running with 8 increments of sol106 only.

Thanks in advance for your support

Re: ERROR-NX- allocated Memory

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Wazy,

Yes, the default solver with NX NASTRAN is the DIRECT SPARSE solver:

 

  • The sparse direct solver is a robust and reliable option, well-suited to sparse models where accuracy is desired.
  • The element iterative solver performs well with solid element-dominated models. It may be a faster choice if lower accuracy is acceptable.
  • You can optionally define the SMETHOD case control command and the ITER bulk entry to alter any of the default options available on the ITER entry.
  • For problems involving contact and 3D solid elements, the element iterative solver is generally faster as compared to the sparse direct solver.
  • For large problems use buffsize=65537A larger BUFFSIZE takes fewer requests of the computer operating system to transfer the same amount of data, with each transfer involving a larger physical record size. This can reduce the I/O time which, in turn, reduces the elapsed time. In general, the effect on CPU time is insignificant. A larger BUFFSIZE decreases the number of I/O operations but may increase the database size. Since each data block uses at least one buffer and the read/write operation requires a minimum of one buffer, the default BUFFSIZE is recommended except for large problems.
  • Use PARALLEL=8. 
  • Parallel=value specifies the maximum number of CPUs selected for shared-memory parallel (SMP) processing in several numeric modules. SMP processing reduces elapsed time at the expense of increased CPU time. The default is 0, which specifies no SMP processing. If “parallel=1", the parallel algorithms are used on one processor.

In summary, to speed the solution time and increase the NX NASTRAN performance (running with any pre&postprocessor, say SIMCENTER or FEMAP) you can do the following:

  • use a fast SSD drive for SCRATCH,
  • increase RAM memory, and
  • of course, use the faster processor as possible!!.

You can learn more about NX NASTRAN PERFORMANCE visiting my blog: 
https://iberisa.wordpress.com/2016/03/21/requisitos-hardware-nx-nastran-ii/

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: ERROR-NX- allocated Memory

Builder
Builder

Thanks Blas for the very valuable details here.

So how to define the buffsize? is it inputted in the .dat file? (I assume that before running the software write the input file then edit the dat file and insert the command in the first line. afterwards, we can run the software?
is not there a way to define the buffsize it in the Entry bulk parameters?

 

The temp folder destination is it changed through the environmental variable API_DEFAULT_DIR, please? 

 Thanks

Re: ERROR-NX- allocated Memory

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Wazy,

You need to locate the nast11.rcf file, this is the nastran resources configuration file, Go to "../nastran/conf" and edit the file nast11.rcf using NOTEPAD, there make sure to edit the nastran keyword SDIR to point to the correct location of SCRATH directory. For instance, in my system SDIR=C:\SCRATCH means that the nastran scratch will be created in the location C:\SCRATCH, where I have a fast SSD drive, plenty of space. 

nastran-configuration-file.png

For superior nastran performance, is better to have a dedicated separate fast SSD drive for only nastran scratch, like D:\SCRATCH using a fast PCIe m.2 SSD drive with say 1 GB of disc space!!.

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: ERROR-NX- allocated Memory

Builder
Builder

Hi Blas, 

Please see the attached nast10. file. Do I need to copy exactly same that you post or only points you have highlighted, please?

Can I edit while the NX is running?

 

Thanks

 

Re: ERROR-NX- allocated Memory

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Wazy,

Don´t copy, the highlighted ones are OK.

You can edit the nasxx.rcf file any time you like, but to take effect the changes you need to execute again the NX NASTRAN solver.

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: ERROR-NX- allocated Memory

Builder
Builder

Hi

 

Unfortunately, no change at all. I am not sure if there are more things to do. I am using less than my original model with the least order element and it is run with one step/2hrs. Actually, I'm pretty sure now it is a little bit slower than earlier case17hr/8 vs 15hr/8steps) I am not sure if I used the original model how much running time would cost? 

The challenge we needing several runs before validating the model.

Any suggestion, please?

 

Thanks

Re: ERROR-NX- allocated Memory

Builder
Builder

Hi,

 

Is it possible to use mass-scaling in NX for accelerating the static nonlinear analysis, please?

 

Regards