pvm_spawn

Scilab function
Last update : 13/07/2005

pvm_spawn - Starts new Scilab processes.

### Calling Sequence

  `[tids, numt] = pvm_spawn(task, ntask, [nw], [where])`

### Parameters

- `task : string, which is the file name of the scilab script (see exec) to be`started. The Scilab script must already reside on the host on which it is to be started. The name must an absolute path.
- `ntask`: integer, specifying the number of copies of the scilab script to start.
- `win`: string (optional). If win is equal to ``nw'' the Scilab process will be spawned in background with out any window coming up.
- `where`: string (optional), can be a host name such as ``tequila.ens-lyon.fr'' or a PVM architecture class such as ``SUN4''.
- `numt`: integer, the actual number of tasks started. Values less than zero indicate a system error.
- `tids`row of integers, array of the tids of the PVM processes started by this pvm_spawn call.

### Description

`pvm_spawn` starts `ntask` copies of the scilab script `task`.

On systems that support environment, `pvm_spawn` passes selected variables from parent environment to children tasks. If set, the envar `PVM_EXPORT` is passed. If `PVM_EXPORT` contains other names (separated by ':') they will be passed too. This is useful for e.g.:

     setenv DISPLAY myworkstation:0.0
     setenv MYSTERYVAR 13
     setenv PVM_EXPORT DISPLAY:MYSTERYVAR

The hosts on which the PVM processes are started are determined by the `where` arguments. On return the array `tids` contains the PVM task identifiers for each process started.

If `pvm_spawn` starts one or more tasks, `numt` will be the actual number of tasks started. If a system error occurs then `numt` will be < 0.

If `numt` is less than `ntask` then some executables have failed to start and the user should check the last locations in the `tids` array which will contain error codes (see below for meaning). The first `numt` tids in the array are always valid.

When the argument `where` is omitted an heuristic (round-robin assignment) is used to distribute the `ntask` processes across the virtual machine.

In the special case where a multiprocessor is specified by `where` `pvm_spawn` will start all copies on this single machine using the vendor's underlying routines.

### See Also

`pvm`, `pvm_spawn_independent`,