Specific Options

“{-x} {-f=C:\Program Files\Altair}”

1. These options may or may not be supported by each solver. Verify with solver specific manual for detailed information about such options.
2. The value passed to the -args option has to be interpreted by tclsh (internal to ACC) thus requires non-intuitive quoting for spaces and special characters. Usually the value of this option contains multiple options and values attached to the final command line separated by spaces and the quoting is as in the example – whole list is quoted by double quotes (if used in ACC GUI) or by single quotes (if used on Linux command line), each argument is enclosed in curly braces, if it contains spaces, and quotes, parentheses or backslashes internal to each argument may need to be quoted by backslash.

• Shared memory parallelization, often referred to as multi-threading, SMP, or OpenMP. The solver runs as a single process on a single computer host and uses internally multiple cores to speed up operations which can be performed concurrently. To start the solver in this mode use option ‘-nt N’. Typically, it is expected that the value N on this option will not exceed the actual number of available cores, but it is not an error to use larger N (check the manual in such cases).
• Distributed processing parallelization, also called message passing (or MPI), or SPMD. In this mode, the external utility (usually named mpirun) is started first, and this utility starts multiple instances of solver. These instances communicate with each other as needed, as they typically each handle part of all data – all these instances can be started on a single host or on a cluster of hosts, but internally it does not matter to how the solver does its job. To start the solver in this mode, use option -np N and add -hosts or -hostfile options to define which hosts should be used by multiple instances of solver. When only the -np option is used, all instances will run on a single host. When -np is not present, but -hosts or -hostfile options are present, the ACC assumes -np is equal to the total number of declared hosts.
• In MPI mode, each instance of the solver can internally run in OpenMP mode to speed things up, this is sometimes called mixed mode and is often faster than pure MPI or pure OpenMP. To start the solver in this mode, together use options from both groups above, example, -np N1 -nt N2. These two modes are independent and can usually be mixed easily during programming.
• In general, both types of parallelization expect that there are enough CPUs and hosts available, but there is nothing wrong with running MPI job even on a host with a single core CPU (if you can find one today). In some cases – example being OptiStruct MMO mode – the value of -np is dictated by the solver or specific input data, not by the available hardware.
• Usually, MPI runs are performed on a group of hosts similar in size and hardware, but theoretically it is possible to start MPI run with hosts using different architecture, and even different operating systems. This topic is outside of the scope of ACC.

• Using -cores auto -np N is not recommended, but is possible. ACC will probe the host (or hosts, if specified) and decide on value for -nt option based on available cores.

1. For MPI runs, it is necessary to provide enough information for ACC (or PBS) to know how many hosts/processes should be used. Usually either -np, -hosts, or -hostfile is sufficient.
2. When -hosts is combined with -cores, possible duplicates in the hostnames will be deleted.
3. The simplest format of hostfile is usually one hostname per line.
4. Format of hostfile is specific to each MPI distribution, verify with vendor documentation.
5. Use of -appfile will often override some items which ACC uses to run a solver. In particular, the name of executable and arguments to call on each host will be used as defined in this file.
6. -mpitest is available only when Altair HWSolvers package is installed.
7. For historical reasons, some solvers may use option names which do not conform to the above list.
8. Verify with solver manual if the solver supports multi-processor runs, what types of multi-processing is available, and specifically, which MPI vendors are supported.

• Command line syntax for batch execution.

  ACC is written almost entirely in Tcl/Tk and the command line must follow that syntax. The main implication is how to properly quote strings containing spaces and special characters, and in some cases it is necessary to quote within quotes. Then there is interaction of syntax of the shell used to execute the command, which may have different quoting rules, and there is no way to discuss all special cases here. Similar quoting requirements apply when entering options in the GUI entry fields.

  Double quotes are used to allow the spaces inside the names, typically filenames:

  acc -core in “path with spaces/input.fem”

  Curly brackets are used to prevent special characters (example, backslash) from being treated as special characters.

  acc -core in {C:\path with spaces\input.fem}

  This will also work:

  acc -core in {path with spaces/input.fem}

  A backslash can be used to escape single character. In this case, spaces are part of the name, instead of separating items in the line:

  acc -core in path\ with\ spaces/input.fem

  ACC has special options (-args, -mpiargs, -acu_fsi_args) which allow an arbitrary list of arguments to be passed down to a next phase of execution. Here are examples how to achieve quoting in such cases:

  acc … -mpiargs “ -envall -n 6 ”
  acc … -args { -core=in -name={Program Files\WINDOWS\etc} }

  Here, nested brackets are used, outside brackets to group two parts into the value to -args, inner brackets are needed to protect space and backslashes inside this single filename.

  Note: The space before the -core… is required, as it prevents acc from reading the minus in -core=in as a name of option.
• Batch execution of FSI run

  Two options specified for FSI runs are: -acu_fsi and -acu_fsi_args

  To invoke batch execution of any solver with AcuSolve (where ‘any solver’ currently may be, example, OptiStruct, MotionSolve or EDEM), the arguments for AcuSolve must be passed as a single value for -acu_fsi_args:

  <ALTAIR>/common/acc/scripts/acc <input for MS> <args for MS>
       -acu_fsi {file for AS} -acu_fsi_args {args for AS}

  In the example inside HyperShape, it could be:

  … -file Motion.xml -solver MS -nt 2 -acu_fsi ${root filespec_resource}
     -acu_fsi_args " -args { -np 4 -tlog } "

  Note: ${root filespec_resource} is part of the shell used by HyperShape, so the ACC will receive this part as:

  -file Motion.xml -solver MS -nt 2 -acu_fsi file_0005 -acu_fsi_args
        " -args { -np 4 -tlog } "

• Remote job submission in the batch mode

  Options specific for the remote execution are -remote, -copyoptions, -jobstatus. In addition, for PBS server there are -pbschunks, -pbscpu, -pbsmem. Related options are also -pushfile and -filelist.

  To submit a job to any remote server, simply append -remote <remote_name> to the command used for local execution, example:

  acc <input file> -remote Linux_server_1

  Optionally, -copyoptions may be used to define how to treat results:

  acc <input file> -remote Linux_server_1 -copyoptions fc:1,pc:0,dr:1

  -remote [name]

  Submit job to a remote machine. Argument is the name of the remote machine that is configured in the GUI.

  -copyoptions [name,value]

  Options to copy the results from remote server (optional), default is fc:1,pc:0,dr:1 (copy full results and delete results directory on remote).

  fc

  Full copy

  pc

  Partial copy (post-processing files)

  dr

  Delete results directory on remote

  0

  Disables the option

  1

  Enables the option

  When a job is submitted to a remote PBS server, additional resources may be specified.

  acc <input file> -remote Linux_server_1 -pbschunks 4

  pbschunks [value]

  Number of chunks (optional), default is 1.

  Chunk is the minimum unit which can be requested, usually it is a computer; however, sometimes a PBS installation may allow n tasks to run on each computer. In this case, chunk represents 1/n-th of a computer.

  pbscpu [value]

  Number of cpu’s (optional), default is 2.

  pbsmem[value]

  Memory in GB (optional), default is 4.

  To check the status of any remote job, issue command:

  acc -jobstatus flock_122

  jobstatus [name]

  Check status of remote job submitted. Argument is JOBID generated by ACC.

  showremotejobs

  List jobs submitted to remote servers. No argument is required.

• OptiStruct solver has built-in capability to ‘preread’ the input data, and produce a file containing a complete list (refer to the option -inventory, in the OptiStruct Reference Manual).
• Altair Manufacturing Solver (Injection Molding) input file (*.ams) contains a complete list of input files needed for the run, created by the pre-processor specific for the solver.
• For all other solvers, ACC has built-in default rules to locate needed files, but such rules may not be sufficient in some cases. You can still submit the run in these cases by adding more files to the default selection, using options:

  -pushfile <filename>

  To add one file (option can be repeated as many times as needed).

  -filelist <filepath>

  Where argument to this option defines filename containing a list of files in XML format (identical to the one automatically created by OptiStruct).

• All files needed for the run (identified automatically and added with -pushfile or -filelist options) are copied to the same folder on a remote host where the solver is going to be executed. When input files are presented in the complex multi-level structure, their location on the remote server will not match such structure and the solver may not run properly.
• For OptiStruct, the special option, -asp allows running such a job correctly.
• For any solver, ACC is not currently able to properly submit the job when filenames overlap. In rare cases when this happens, it is necessary to rename such files and modify include statements to resolve conflicts.

<results_catalog>
   <input   name="run.fem"/>
   <input   name="qadiags.inc"/>
   <input   name="../test_io/qadiags.inc"/>
   <input   name="../test_io/inc_1.fem"/>
   <input   name="../test_io/inc_2.fem"/>
   <input   name="../test_io/SUBDIR1/inc_11.fem"/>
   <input   name="../test_io/SUBDIR1/SUBDIR11/iii1.fem"/>
   <input   name="SUBDIR2/iii2.fem"/>
   <data    name="../testnp100/cms_cbn_testinrel.h3d"/>
 </results_catalog>