Mechanical APDL Basic Analysis Guide

Learn your memory requirements Use the BCSOPTION command to determine how much memory
your job requires (when running the shared-memory sparse solver). Set your -m and -db appropriately.
Too little memory, and your job cannot run; however, setting an unnecessarily high -m prevents the
program from using available memory to reduce I/O time. T o use this command, add the following to
your input:

BCSOPTION,,,,,,PERFORMANCE

Then run your job and review the output file message to see how much memory you need. If possible,
reduce your -db setting and increase -m so that you can get a sufficient memory block for both assembly
and solution.

Optimize your job and your system After you understand your maximum memory settings and the
memory required for your job, you can try the following suggestions to further optimize your environ-
ment.

• For large jobs with memory requirements close to your system's limits, run the solution phase as a
  batch job with minimal -db space (usually 64 MB) and force the database memory not to grow (i.e.,
  use a negative number such as -db -64). Before postprocessing, increase the -db and resume the
  jobname.db file and run interactively.


• For nonlinear jobs, try some preliminary runs, restricting the number of cumulative iterations using
  the NCNV command. Be sure to use BCSOPTION and review the output for your performance summary.
  Based on the performance summary, you can choose to run in-core, optimal out-of-core, or out-of-
  core.


• Always try to run comfortably within the system memory resources. Run your job in optimal out-of-
  core mode and use less of your system's total available memory.


• You should have 2 GB of real memory as a minimum if you are running large jobs. Set the system
  page file for 3 GB, and use the /3GB switch. However, at the /3GB switch to a separat e copied line at
  the end of the boot.ini file so that you can reboot Windows in normal or /3GB mode.


• Have 100 GB of available disk space to run your jobs. Do not put everything on your C: drive. Regularly
  defragment your working directory, and move permanent files to another location after the job runs.

5.4. Using Special Solution Controls for Certain Types of Structural Ana-

lyses

When you are performing certain types of structural analyses, you can take advantage of these special
solution tools:

• Abridged Solution menus, which are available for static, transient (all solution methods), modal, and
  buckling analyses. See Using Abridged Solution Menus (p. 120).


• The Solution Controls dialog box, which is available for static and transient (full solution method only)
  analyses. See Using the Solution Controls Dialog Box (p. 121).

5.4.1. Using Abridged Solution Menus

If you are using the GUI to perform a structural static, transient, modal, or buckling analysis, you can
use either abridged or unabridged Solution menus:

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Solution