Running Radioss

Schedule multiple simulations.

The simplest solution is to use the Altair Compute Console. It will automatically sequentially run all Engine files located in the run directory. It will also queue different simulations and run them sequentially.

For more advanced job queuing, PBS can be used.

Check the version and cpu used.

The version used in a simulation is written to the Starter (*0.out) and Engine (*1.out) output files.

In the Engine output file header, the software version, hardware information, and the parallelism type are written.

Example (Run with Radioss version 2018)
************************************************************************
**                                                                    **
**                                                                    **
**                   Altair Radioss(TM) ENGINE 2018                   **
**                                                                    **
**            Non-linear Finite Element Analysis Software             **
**                   from Altair Engineering, Inc.                    **
**                                                                    **
**                                                                    **
**              Linux 64 bits, Intel compiler, Intel MPI              **
**                                                                    **
**                                                                    **
**                                                                    **
** Build tag: 0926169_126382018_2070_0056977_10                       **
************************************************************************
**  COPYRIGHT (C) 1986-2018                 Altair Engineering, Inc.  **
** All Rights Reserved.  Copyright notice does not imply publication. **
** Contains trade secrets of Altair Engineering Inc.                  **
** Decompilation or disassembly of this software strictly prohibited. **
************************************************************************
 
 NUMBER OF SPMD DOMAINS           4
 NUMBER OF THREADS PER DOMAIN    12
 NUMBER OF HMPP PROCESSES        48
  
 COMPUTATION HARDWARE DESCRIPTION
  
 CPU#  HOSTNAME     CPU TYPE, FREQUENCY AND MEMORY
   1   n008   Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (x86_64), 2501 MHz, 129088 MB RAM,   7950 MB swap
   2   n008   Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (x86_64), 2501 MHz, 129088 MB RAM,   7950 MB swap
   3   n009   Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (x86_64), 2501 MHz, 129088 MB RAM,   7950 MB swap
   4   n009   Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (x86_64), 2501 MHz, 129088 MB RAM,   7950 MB swap
  ************************************************************************
Comments
  1. On the fourth line you can see that it is a 2018 Radioss version and on the line after that it is a Linux version.
  2. Check the NUMBER OF SPMP DOMAINS, and NUMBER OF THREADS PER DOMAIN.
    • Since the number of SPMD domains is > 1 and the number of threads by domain is 1, the Hybrid MPP is being used.
    • If only SMP is used, then the NUMBER OF SPMP DOMAINS = 1.
    • If only SPMD is used, then the NUMBER OF THREADS PER DOMAIN =1 and the NUMBER OF SPMP DOMAINS > 1
  3. The NUMBER OF HMPP PROCESSES is equal to NUMBER OF SPMP DOMAINS multiplied by the NUMBER OF THREADS PER DOMAIN. This is the total number of cores used in the simulation.
  4. The CPU# is the list of hostnames for each SPMD domain.

Run with multiple SMP threads per domains.

It is now possible to launch Starter, as well as launch Engine, using more than one SMP thread by SPMD domain. The simplest method is to use the Compute Console (ACC) GUI or script and specify -nt. For example, if using the script,
  • Run Starter using 12 threads and Engine with 12 threads and 4 domains:
    radioss -nt 12 -np 4 input_0000.rad
  • Run Starter and using 12 threads and Engine with 1 thread and 48 domains. This must be done using two commands.
    radioss -nt 12 -np 48 -onestep input_0000.rad

radioss -nt 1 -np 48 -onestep input_0001.rad

To run the Radioss executables directly and not use the Compute Console (ACC), refer to Run Executables Directly in the User Guide.

How to set the number of cores for a run.

Use the Compute Console (ACC) and specify the -nt and -np parameters. Refer to From Altair Compute Console (ACC) in the User Guide.

The total number of cores used will be the -nt input multiplied by the -np input.

Starter stops with message: OUT OF SPACE IN DOMAIN DECOMPOSITION.

OUT OF SPACE IN DOMAIN DECOMPOSITION
(8) PLEASE INCREASE MEMORY FOR THE DOMAIN DECOMPOSITION

This message means that Radioss Starter is not able to process domain decomposition with the default amount of memory allocated (SPMD computation).

The needed memory is computed by Radioss Starter before the model decomposition. In most cases it is enough; but in the case of complex meshes and a lot of connectivity (for example: a model with a lot of solid elements), this memory allocation has to be increased.

This can be done by setting the Dkword value in the fourth field of the option /SPMD:
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
Domdec Nspmd   Dkword   Nthread        
Note: This only concerns the memory requested by Radioss Starter, not the memory allocated for Radioss Engine.

Set the stacksize for running Radioss.

Before running Radioss it is important to properly define the amount of stacksize memory.

Under Linux, stacksize must be defined as unlimited.
  • Using csh:
    limit stacksize unlimited
  • Using sh:
    ulimit –s unlimited

Additionally, in case of running Radioss SMP with more than one thread (OMP_NUM_THREADS greater than one), it is important to define an additional environment variable KMP_STACKSIZE, which defines the per thread stacksize.

Under Linux, the recommended value is 512 Mbytes.
  • Using csh:
    setenv KMP_STACKSIZE 512m
  • Using sh:
    export KMP_STACKSIZE=512m

Under Windows, the recommended value is 64 Mbytes.

  1. Click on start\Settings\Control_Panel\System\Advanced\Environment_Variables\System_Variables\New
  2. Define a new Variable KMP_STACKSIZE with Value 64m.
  3. Double-click the OK button to validate your modification.

    Then, any new shell running Radioss will have the environment variable KMP_STACKSIZE defined to 64m.

Below is a summary of the recommended values automatically set by HyperWorks when running Radioss from a standard HyperWorks installation:
Variable Stacksize KMP_STACKSIZE
Windows N/A 64m
Linux Unlimited 512m