Asynchronous Solution

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Asynchronous Solution

• Chapter Eleven

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Chapter Overview

• In this chapter, the use of Simulations
  asynchronous solution capability will be covered
• Asynchronous Solution Overview
• UNIX Server
• LSF Cluster
• Workbench Cluster
• ANSYS Product Table
• The capabilities described in this section are
  applicable if an additional license of ANSYS
  Professional licenses and above is available.

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A. Asynchronous Solution Overview

• By default, when a user solves a model,
  Simulation starts the ANSYS batch solver on the
  same machine
• In some cases, especially with very large models,
  it may be preferable to perform the solution on a
  separate machine. Simulations asynchronous
  solution capability makes this possible.
• In this situation, the model is setup on a client
  machine, but the numerical solution is performed
  on a server or cluster.

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Details on Async. Solve

• There are two methods (discussed shortly) where
  solving can be performed on a different machine
  (server)
• UNIX Server a UNIX machine (e.g., SUN, IBM, HP,
  SGI) is used to perform the solution
• LSF Cluster an LSF cluster1 is used to perform
  the solution
• For asynchronous solution, the following is
  performed
• The model is set up on the users client PC as
  normal.
• Attaching geometry, defining contact regions,
  apply loads, etc.
• When asynchronous solution is initiated, the
  necessary information is sent to the server which
  runs the ANSYS solver.
• This is performed automatically. Simulation
  provides a means of monitoring the status of the
  job(s) submitted.
• When the solution is complete, the user can
  retrieve the results back to the client PC for
  postprocessing.
• Reviewing all results is done as normal on the
  client PC.

1 LSF is a product of Platform Computing
(http//www.platform.com)
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Requirements for Async. Solve

• To take advantage of asynchronous solution, the
  following requirements must be met
• The client (users) machine must be running
  Windows
• UNIX versions of Simulation currently do not
  support asynchronous solution
• An additional license of ANSYS Professional or
  above
• The client may be running any supported license,
  such as ANSYS DesignSpace, but to use
  asynchronous solution, an additional license
  (ANSYS Professional or above) is required for
  solution done on the server.
• No Postprocessing Commands or Parameter Manager
  branch may be present in the Simulation model
• Postprocessing Commands branch or Parameter
  Manager branch require the solution to be
  performed locally
• A UNIX server (with a valid user account) or an
  LSF cluster must be present
• For example, asynchronous solution cannot take
  advantage of another Windows machine not on an
  LSF cluster

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Procedure for Using Async. Solve

• To use asynchronous solution, simply set up the
  model as normal, then go to the Details view of
  the Solution branch
• Change Run Solver Process on to either UNIX
  Server or LSF Cluster, whichever may be
  appropriate
• Click on the Solve button on the toolbar to
  initiate asynchronous solution
• The Solution Status page will be displayed,
  allowing users to monitor the progress ofthe
  submitted job(s).
• After solution is complete, as indicatedon the
  Solution Status page, the results can be
  retrieved.
• Review results in Simulation as normal.

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Procedure for Using Async. Solve

• Note that the number of processors to use, as
  specified under Tools menu gt Options gt
  Simulation Solution will be taken into account
  on the server machine.
• For example, if multiple processors on a UNIX
  server are to be used, set the Number of
  Processors to Use accordingly
• For users familiar with ANSYS solver memory
  management, the workspace (-m) can be specified
  via Tools menu gt Variable Manager.
• Add a variable AMK MEMORY and specify the value
  (in MB) to be used. The ANSYS solver will be run
  with this setting
• The database space (-db) is specified in a
  similar manner with an undocumented variable,
  AMK DBMEMORY

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Solution Status Page

• When asynchronous solution is specified under the
  Solution branch Details view, the Job Status
  tab becomes available to display under the
  Graphics Window

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Outline Tree Status

• Asynchronous solution provides a few slightly
  different status icons on the Outline Tree
• A green lightning bolt means that solution is
  running or is pending
• A red lightning bolt indicates that an error
  occurred during solution
• A green down-arrow signifies that the results are
  ready to be retrieved
• A red down-arrow means that there was a problem
  during asynchronous solution, such as
  communication with server

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Retrieving Results

• After solution is completed successfully (green
  down-arrow icon), right-click on the branch to
  Get Results. Then, resultscan be reviewed as
  usual.
• Note that even if a solution failed (red
  down-arrow icon), right-click and select Get
  Results to get further information on why the
  solution was not successful

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B. UNIX Server

• If a UNIX machine is available, it can be used
  for asynchronous solution
• Must have the same version of ANSYS installed and
  be a supported UNIX platform
• User must have a login account

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Specifying UNIX Server

• To specify the UNIX Server in Simulation, specify
  login information in the Solution branch Details
  view

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UNIX Server Troubleshooting

• Consult the Simulation online help
• Simulation Help gt Troubleshooting gt Problem
  Situations gt Problems Unique to Asynchronous
  Solutions
• Other troubleshooting tips
• Log into the UNIX server (via telnet, ssh, etc.)
  when asynchronous solution is initiated to
  interactively monitor processes files
• An ftpd process should be running prior and after
  solution is done on UNIX. This process transfers
  the input and output between the client and
  server.
• A directory with a long name, beginning and
  ending with x, should be generated in the
  working directory. ds.dat is the input file
  transferred to UNIX, and filexx.xml should be
  generated after solution is done. This directory
  will be cleaned up upon successful completion of
  solution.
• Check to see if ftp and rexec from client to
  server is possible.
• Check to see if ANSYS can be run successfully
  from UNIX (ansys81).
• On the Windows client
• During solution, JMService.exe and
  CEExeServer.exe processes should be running.
  Check the Windows Task Manager for these
  processes during async solve
• In the Solver Working directory, an ansys_solve
  subdirectory should be generated. When results
  are retreived, .xml files and solve.out will be
  copied to this directory first. This directory
  will be cleaned up upon successful completion of
  solution.

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C. LSF Cluster

• LSF is a third-party software by Platform
  Computing which is used to queue and manage loads
  over a cluster.
• Website http//www.platform.com/
• ANSYS must be installed on the LSF machines
• The users client PC must be part of the LSF
  cluster in order to take advantage of LSF.
  Please refer to Platform Computings LSF
  documentation for details on setting up an LSF
  cluster.
• Although an LSF cluster is used, solution is done
  on a single machine in the cluster

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Specifying LSF Cluster

• After configuring LSF and a Queue, to perform
  asynchronous solution on an LSF cluster, simply
  specify the Queue Name in the Details view of the
  Solution branch

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LSF Cluster Troubleshooting

• Consult the Simulation online help
• Simulation Help gt Troubleshooting gt Problem
  Situations gt Problems Unique to Asynchronous
  Solutions
• Other troubleshooting tips
• The information transferred back and forth from
  the LSF Cluster is in a binary file with a file
  extension .fadb in the Solver Working directory.
• If problems occur, check to see if this file is
  created when solution is sent, and check to see
  if this file is updated when solution is
  retrieved from LSF cluster. This file will be
  cleaned up upon successful retrieval of solution.

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D. Workbench Cluster

• WB Cluster Solution will be submitted to a
  Remote Solution Manager web service. This
  requires that you have a Remote Solution Manager
  network configured according to the ANSYS
  Workbench Products Remote Solution Manager
  Configuration Guide.
• Must specify
• License to Use Specifies the name of a valid
  ANSYS product license (ANSYS Professional or
  higher) for the Remote Solution Manager server.
• Machine Name Specifies the name of the Web
  Service machine that is accessible on your Remote
  Solution Manager network.
• Queue Name Specifies the name of a particular
  queue on the Remote Solution Manager network
  (note this option appears only if you entered a
  Machine Name other than localhost).

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. . . Specifying Workbench Cluster

• The web service machine name may be localhost
  or remote machine name.
• Localhost specifies the client machine as the
  web service and server.
• If machine name is not localhost a queue name
  must be provided.
• Number of processors may be from 1 to 8 (default
  2).

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. . . Remote Solution Manager

• Remote Solution Manager is primarily a Web
  Service (i.e. web site with a URL such as
  lthttp//web_service_machine/CEgt).
• The Remote Solution Manager administrator
  configures queues and compute servers that will
  be available to Workbench clients.
• Workbench clients submit solutions to the Remote
  Solution Manager Web Service which then
  distributes them to the compute servers.
• Solutions are queued up and wait for a server to
  become available.
• See the ANSYS Workbench Products Remote Solution
  Manager Configuration Guide for details.

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E. ANSYS Product Table

• When specifying the License to Use, the product
  code must be input. This can be found in the
  ANSYS online help (not ANSYS Workbench online
  help)
• Licensing Guide gt Chapter 3. License Files gt 3.4.
  Product Variable Table
• Some typical product codes are below

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Default Settings

• Default settings for asynchronous solution can be
  specified in Tools menu gt Options gt
  Simulation Solution

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