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Altair Accelerator User Guide
Basic tasks in Accelerator, including submitting jobs, tracking job information, and analyzing and solving common problems.
Frequently Asked Questions and Troubleshooting Tips
Troubleshooting X-Windows
If the tool windows are not displayed on the submit host, this is caused by having set the incorrect value of DISPLAY or from not allowing remote hosts to connect.

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What's New
View new features for Accelerator 2025.1.0.
Accelerator Overview
Discover the available Altair Accelerator guides.
Accelerator Tutorials
Discover Accelerator functionality with interactive tutorials.
Altair Accelerator User Guide
Basic tasks in Accelerator, including submitting jobs, tracking job information, and analyzing and solving common problems.
- Use Accelerator Help
  Accelerator documentation is available in HTML and PDF format.
- Accelerator Quick Start
  Accelerator has two main commands, nc and ncmgr.
- Command Line Interface
- Quick Reference
- User Shell Setup
  To set up your user shell with Accelerator you need to know where the Altair Accelerator software has been installed.
- Running a Job
  This section summarizes how to submit and run a job.
- Job Management
- Schedule Job Submission
- Modify Running Jobs
- FairShare Groups
- Job Placement Policies
- Clean Up Log Files
  All log files are normally stored under the subdirectory ./vnc_logs. To remove all obsolete log files in the current working directory, use the nc clean command.
- Debug Jobs without Running Accelerator
  On occasion, jobs that run successfully outside of Accelerator fail when run through Accelerator. When this occurs, mostly likely the setups are not the same: the environment, inputs or other parameters may be different, a misconfiguration or there is a problem with NFS.
- Job Runtime - Monitor and Profile
  When a job is running through a vovtasker, the tasker automatically monitors RAM and CPU utilization of the job, including all of its children.
- Monitor the Workload
- Statistical Information about Resources and Jobs
  Reports provide statistical information about all the jobs that are run during a specified time and the usage of the resources that run jobs. The resources include CPU time, licenses, memory and more.
- Environment Control
  Setting the environment is critical for correct job execution. Accelerator provides two methods to control the execution environment.
- Job Resources
  Some jobs may require a specific platform or operating system (OS) to run. As Accelerator automatically lists platform/OS as a tasker resources, the task of finding the right host to execute a job is easy: specify the required platform/OS as part of the job resource requirements.
- Advanced Information
- Frequently Asked Questions and Troubleshooting Tips
  - Frequently Asked Questions
  - Simulation Scripts
    This section describes job simulation scripts that emulate jobs. Such scripts are often used by developers as well as business systems analysts.
  - Accelerator GUI
  - Cores, Slots and CPUs
  - Troubleshooting X-Windows
    If the tool windows are not displayed on the submit host, this is caused by having set the incorrect value of DISPLAY or from not allowing remote hosts to connect.
  - Sanity Check for vovserver
    The command sanity is used to perform checks on the consistency of the trace and of other internal data structures.
  - Qualify the Working Directory of Jobs
    The working directory is the directory from which the job is submitted. For the job to execute correctly, the working directory must exist on the remote host. Directories that are not reachable by all machines in the network should be avoided; this can cause jobs to fail.
- Deprecated Commands
  This section lists the recently deprecated and obsoleted Accelerator commands and options, and the corresponding current commands and options.
- LSF Emulation
  This document is intended for those who have been using the Platform LSF batch system and are now moving over to the Accelerator system.
Altair Accelerator Administrator Guide
Configure and manage the use of Accelerator after it is installed.

View All Altair Accelerator Help

Troubleshooting X-Windows

If the tool windows are not displayed on the submit host, this is caused by having set the incorrect value of DISPLAY or from not allowing remote hosts to connect.

You should use the xhost + command on the machine where the windows should appear so that the farm hosts are permitted to display there. If you do not wish to permit all hosts to connect, use xhost +farm-host-name for the desired hosts.

There is an option to the X-server -nolisten tcp that causes the X-server to only accept client connections from the local host. This option is typically used with the secure shell, ssh, that automatically sets the DISPLAY to localhost:NN and port-forwards the connection back to the host from which you logged in.

Linux distributions may ship with -nolisten tcp enabled by default. With this setting, jobs from farm hosts cannot connect.

To configure your X-server so that remote hosts can connect, re-start the X-server without the -nolisten tcp option. This action requires root access to your machine.

Note: If there is a security policy that prohibits non-tunneled X-windows protocol, executing this change may also require coordination with your IT department.

The following are instructions to configure the X-server on two platforms:

Red Hat Enterprise Linux

Use the command gdmsetup as root.
Uncheck Always disallow TCP connections to the X-server in the Security tab.
Log out as root, then re-login as yourself.

SuSE 9.1 Pro Linux

A section in the file /etc/sysconfig/displaymanager that contains an envVar that controls whether remote clients are allowed to connect.

The following is the relevant section of the file:

## Type:        yesno
## Default:     no
#
# Tcp port 6000 of Xserver. When set to "no" (default) Xserver is 
# started with "-nolisten tcp". Only set this to "yes" if you really
# need to. Use ssh X11 port forwarding whenever possible.
#
DISPLAYMANAGER_XSERVER_TCP_PORT_6000_OPEN="yes"