How to Launch Flux via Command Line?

What’s New

Here is a quick look at the latest features available in Flux 2021.1.

A command line option to set directly environment variables is available:

-env <environment variable=value>

Command-line interface

The following commands are valid for Flux 2021.1. The Flux executable can be found in the installation directory FLUX_HOME. By default, FLUX_HOME is:

On Windows: FLUX_HOME= C:\Program Files\Altair\2021.1\flux\Flux
On Linux: FLUX_HOME=/root/2021.1/altair/flux/Flux

The Flux executable is located at FLUX_EXE:

On Windows: FLUX_EXE=%FLUX_HOME%\Bin\prg\win64\flux.exe
On Linux: FLUX_EXE=$FLUX_HOME/Bin/prg/lin64/flux

You can find below the command line to launch Flux depending on the application 2D, Skew, 3D or PEEC:

On Windows: %FLUX_EXE% –application <app> [options]
On Linux: $FLUX_EXE –application <app> [options]

with <app> = Flux2D, FluxSkewed, Flux3D or FluxPEEC

The options are listed below:

[options]	Function
-batch	to launch Flux in batch mode. The batch mode enables Flux to be launched without user interface.
-newproject	to create a new project with the <app> application.
-file <fluxProject>	to open an existing project located at <fluxProject>. fluxProject is the path to the Flux project (C:\work\project1.FLU, for example).
-runPy <pyFile>	to launch Flux and run a python script located at <pyFile>.
-runPyInSilentMode <pyFile>	to run a python script located at <pyFile> with the user interface frozen and being refreshed only at the end of the execution of the python script.
-runPyInSilentModeAndExit <pyFile>	to run a python script located at <pyFile> with no graphical refresh, and then exit. Using the command runPyInSilentMode may not terminate the Flux process when encountering an error.
-env <environment variable=value>	to set environment variable with value. (Mutiple arguments authorized)
-application [Flux2D, Flux3D, FluxSkewed, FluxPEEC]	to start Flux2D, Flux3D,FluxSkewed or FluxPEEC
-memsizn3_mb <m>	to start with m numerical memory in MB
-memsizc3_mb <c>	to start with c character memory in MB
-fluxncores <n>	to start with n cores
-help	to display the help.

Note:

<pyFile> is the path to the python script to run (Example: C:\python\project1.py).
the application <app> must be the same as the python script to run or the Flux project to open or create.

To be able to launch Flux, the next environment variables must be defined.

Environment variables

To set an environment variable:

On Windows, use the set command, as below:
set MY_VAR=2

Or by command line:

-env MY_VAR=2
On Linux, in the case of common interpreter sh, ksh and bash, use the export command (see example below):
export MY_VAR=2

Or by command line:

-env MY_VAR=2

Mandatory environment variables
The mandatory environment variables are listed below:
- Number of cores to use: FLUX_NCORES.
  Use FLUX_NCORES=<NCORES> to use NCORES cores.
  
  If NCORES=0, Flux will use all the cores available.
- Numerical memory (in Bytes): MEMSIZN3.
  
  The numerical memory is the memory used for the different modeling actions (import, mesh, solving process, ...).
  Warning: For PEEC, this is not this memory which is used for the solving process, but JVM_MEMORY (see below "GUI memory + PEEC Solver").
  
  If user enters a value different from 0 in this variable, Flux will be executed in static (or user) memory mode with the memory amount set in this variable.
  
  A variable value of MEMSIZN3=0 will launch Flux in dynamic memory mode.
- Character memory (in Bytes): MEMSIZC3.
  The character memory is the memory used for the storage of entity names (parameters, transformations, regions, conductors, …) and the project names in the working directory.
  
  If user enters a value different from 0 in this variable, Flux will be executed in static (or user) memory mode with the memory amount set in this variable.
  
  A variable value of MEMSIZC3=0 will launch Flux in dynamic memory mode.
- GUI memory + PEEC Solver (in MiB): JVM_MEMORY.
  This memory is the memory used for everything related to the Graphical User Interface (graphical display, …).
  Warning: For PEEC, this memory is also used for the solving process.
  Default value for:
  - 2D: JVM_MEMORY=1024
  - Skew: JVM_MEMORY=1536
  - 3D: JVM_MEMORY=2048
  - PEEC: JVM_MEMORY=4096
Additional environment variables
You can find below a list of optional variables:
- Allow multiple instances of Flux on the same machine:
  
  Set the variable SYNC_SOCKET=0.
- Force linear solver for pre and main resolution:
  
  FORCE_FLUX_SOLVER and FORCE_FLUX_PRESOLVER, respectively.
  
  These 2 variables allow to force a specific solver (Mumps, ICCG, SuperLu…). When solving the project, the solver used is the one defined in the environment variable.
  
  For example:
  
  FORCE_FLUX_SOLVER = LinearSystemSolverMumps
  
  FORCE_FLUX_PRESOLVER = LinearSystemSolverIccg
  
  will set ICCG for pre-solving and Mumps sequential for main solving.
  The possible choices are:
  - Direct solvers:
    
    LinearSystemSolverMumps: Mumps
    
    LinearSystemSolverMumpsDistributed: Mumps distributed
    
    LinearSystemSolverSuperlu: Super LU
  - Iterative solvers:
    
    LinearSystemSolverIccg: Incomplete Cholesky Conjugate Gradient
    
    LinearSystemSolverBiCGStab: BiConjugate Gradient Stabilized
    
    LinearSystemSolverGmres: Generalized Minimum RESidual
  - Others:
    
    LinearSystemSolverByUserSubroutine
    
    LinearSystemSolverAutomatic

Short example

Assuming that all the environment variables are well setted, the command line to open a Flux 3D project is:
- On Windows:
  
  If Flux is installed in C:\Program Files\Altair\2021.1\flux\Flux
  
  And if the Flux 3D project named Project_3D i.e. Project_3D.FLU is located in the directory C:\work
  
  "C:\Program Files\Altair\2021.1\flux\Flux\Bin\prg\win64\flux.exe" –application Flux3D –file C:\work\Project_3D.FLU
- On Linux:
  
  If Flux is installed in /root/2021.1/altair/flux/Flux
  
  And if the Flux 3D project named Project_3D i.e. Project_3D.FLU is located in the directory /home
  
  /root/2021.1/altair/flux/Flux/Bin/prg/lin64/flux –application Flux3D –file /home/Project_3D.FLU
Assuming that all the environment variables are well setted, the command line to start python file “myPython.py” in batch, with 2 cores, in dynamic memory mode, with multiple instances in the same time with no graphical refresh and exit:
- On Windows:
  If Flux is installed in C:\Program Files\Altair\2021.1\flux\Flux
  
  And if the python file is in the current directory, the command line to execute is the following one:
  
  "C:\Program Files\Altair\2021.1\flux\Flux\Bin\prg\win64\flux.exe" -application Flux3D -env MEMSIZN3=0 –env FLUX_NCORES=2 -env SYNC_SOCKET=0 -runPyInSilentModeAndExit myPython.py -batch
- On Linux:
  If Flux is installed in /root/2021.1/altair/flux/Flux
  
  And if the python file is in the current directory, the command line to execute is the following one:
  
  /root/2021.1/altair/flux/Flux/Bin/prg/lin64/flux -application Flux3D -env MEMSIZN3=0 –env FLUX_NCORES=2 -env SYNC_SOCKET=0 -runPyInSilentModeAndExit myPython.py -batch