One method to start/stop the server is interactively using the Grid library functions StartServer and StopServer. These functions are Maple commands and can be used when interactively running or testing grid code from within a Maple Worksheet.

The script, gridserver.sh (Linux) and batch file, gridserver.bat (Windows) start or stop an instance of the Grid Server on a the local computer. These scripts are run from the operating system command interpreter.

The syntax of the gridserver script/batch file is one of

  gridserver [options] startmultiple [port [count]]

  gridserver [options] start         [port [cpu_index]]

  gridserver [options] stop          [port [cpu_index]]

   where one of the following modes can be specified

     start          causes a single Node to start

                    on the indicated port

     startmultiple  causes 'count' Nodes to be started

                    on a single computer beginning at

                    the indicated port.

     stop           halts the Node associated with port.

                    If Node was from a StartMultiple then all

                    Nodes are halted.

   If no mode is specified then startmultiple is assumed.

   and the modes take the following optional parameters

     cpu_index - the index. Should be set zero to allow

                 AutoDiscovery with broadcast.

     port      - the port associated with the Node. If not

                 specified then use port from the -p option or

                 from the configuration file.

     count     - the number of Nodes to start. If not specified

                 the use the -n option or the value from the

                 configuration file.

   Options may be one or more of:

     -a address : UDP broadcast address (e.g 192.168.255.255)

                  for AutoDiscovery. Use 255 to indicate the portion

                  of the subnet to use. This example will

                  broadcast to all computers on the 192.168.*.* address.

     -b port    : UDP broadcast port (e.g. 4400)

                  Set to 0 to disable Autodiscovery.

     -d         : enable debug messages to the log file

     -f file    : path and filename of log file (e.g. logs/grid.log)

                  The path can be relative to Grid Computing Toolbox directory

     -m path    : The full path to commandline Maple binary

     -n num     : number of Nodes to create

     -p port    : TCP/IP base port for the Nodes

Any option not specified will be taken from the configuration file

   conf/grid.properties

The 'startmultiple' starts the specified count of Grid Servers on the same machine. Count should generally not exceed the number of CPUs on the machine as then several instances of Maple will likely use the same CPU instead of being distributed over multi-CPUs. However one reason to set count higher than the number of CPUs is during initial testing of grid code using a single machine. This might be done when a network of Grid Servers is not available. To perform testing using a single machine the following command could be used at the operating system prompt:

gridserver.sh -a 127.0.0.255 -b 4401 startmultiple 2000 5   (Linux)

gridserver.bat -a 127.0.0.255 -b 4401 startmultiple 2000 5   (Windows)

This would start 5 instances of the Grid Server on the local machine each instance using a port from 2000 to 2004.
Jobs would be submitted using the Launch library function after issuing a Setup using localhost (127.0.0.1) and port 2000 as the parameters.

The 'start' command would be used where Autodiscovery is not practical (e.g. Grid Servers are not on a common Internet subnet). In this case each server would be started using an operating system command similar to

gridserver.sh -b 0 start 2000    (Linux)

gridserver.bat -b 0 start 2000   (Windows)

The same port must be used for each computer where the Grid Server is started as well as on the client machine from which the grid code is to be sent from. Access to the Grid Servers started with the 'start' option must be done from either the Launcher script or PBS script shown below. This is because these scripts will receive a file listing the nodes to use in the grid computations.

The 'stop' parameter would be used to terminate the running Grid Server on the local machine.

gridserver.sh stop 2000    (Linux)

gridserver.bat stop 2000   (Windows)

If the server was started with the 'startmultiple' parameter then all instances of the Grid Server on that machine are stopped. For servers started with the 'start' parameter then each instance would require a matching 'stop'  call to halt that instance of the Grid Server.

The servers that will be nodes for this configuration should be setup without Auto-discovery.

The servers that will be nodes for this configuration should be setup with Auto-discovery on so that the host will distribute the job other nodes.

The default location of the  Grid toolbox server installation  is <maple>\toolbox\Grid  where <maple> represents where the main Maple program is installed. Additionally, you should create the directory\shared\mpi plus subdirectories. The directory \shared\mpi\bin will contain additional scripts that are used by client workstations submitting Grid code to the cluster. The file  maple.ini contains generic settings to enable the Grid MPI procedures.

The Maple command Grid[Setup]("mpi", mpidll="msmpi"); instructs the Grid toolbox to use the "mpi" interface instead of the default local implementation. The second argument, "msmpi" refers to the operating system basename of the MPI implementation dll or shared libary. This dll or shared libary should be found in one of the directories named in the PATH environment variable.

Notes:

The \shared\mpi directory on the head node should be shared with all the other compute nodes in the cluster. This is because any Maple GCT code submitted will be stored in the \\headnode\shared\mpi\grid subdirectory. Also any output generated will be stored there.

This directory must allow read/write persmission for Grid users as their temporary files will be place there. User files will be placed in \shared\mpi\grid\<username> where <username> will be the user who submitted the job.    

Also the compute nodes should be configured so that PATH environment variable contains the directory for the cmaple.exe program.

This script can be used to submit a file containing Maple code directly to a  Grid running MPI from an Operating System command line.

Before running the mpilauncher script make sure that Grid cluster is setup as per the instructions in the previous section.

The mpi launcher can be invoked using the following script command and a combination of options and parameters:

<maple>\toolbox\Grid\bin\mpilauncher.bat [-s|-q|-r|-c|-d|-a] [hh|nn|ff|jj|ss]

where the script command parameters are defined as:

and the script command options are defined as:

To submit the Maple script file containing your Maple code use the command:

mpilauncher -s hh nn fff

When you run the mpilauncher.bat script, the Maple script you specified with parameter ff is submitted to the headnode, hh. The headnode then hands copies this script to each of the nn nodes specified, where each node will run the Maple script.

The Maple script is copied to a directory on the head node. The directory will be of the form \shared\mpi\grid\<username> where <username> is the name of the user running the mpilauncher script.

The filename will be of the form maple_jj.code.mpl where jj is the job id for this submission. This job id is then echoed to the console.

Maple output is saved in maple_jj.stdout.txt and maple_jj.stderr.txt. Where jj is the job id.

To check the status of the submitted job use the command:

mpilauncher -q hh jj

where hh is the name of the headnode and jj is the job id of the submission.

The command returns one of the following status messages:

To retrieve the results of a submitted job use the command:

  mpilauncher -r  nn job 

The contents of the file will be returned to the console.

To clean up results and temporary files from the head node use the command:

mpilauncher -c nn job

This will delete the file associated with the job id.