VizSchema

# OnFranklin

# Using VisIt on Franklin

How to use a local machine, an account on franklin.nersc.gov, and the VizSchema database plugin to perform big visualization tasks. 

**How it works**

In normal use, VisIt runs as a set of processes all on a single machine. These processes read data files, present the gui to the user, track metadata, and perform all other tasks necessary for visualization. This method is excellent for small and moderately sized data files since it offers the most responsive interface to the user. However, large datasets and processor-intensive operations can overwhelm a standard desktop machine. 

In order to visualize datasets that are too large for a desktop machine, VisIt allows the user to specify a remote machine to perform certain of the visualization tasks. The data will be loaded and processed on the remote machine, and only the information necessary for visualization will be transferred to the desktop. Although this method of running VisIt is not as responsive as running entirely on a single machine, it can be much faster at generating images and is often the only way to handle large data sets. 

This page will explain how to set up a desktop machine to use Franklin as a remote VisIt system. Note that this is NOT the same as running VisIt as an exported X11 window, which is specifically forbidden by Franklin user policies. 

**Special notes**

* In order to use this method with the VizSchema plugin, the plugin must be installed on the remote machine and the local machine

* The data to be visualized must be available on Franklin

* A login account on Franklin is needed

* An active network connection is needed 

**Installing plugin on Franklin**

First, download the [binary] version of the VizSchema plugin.

Copy the tarball to your home directory on Franklin.

Unpack the files into your home directory on Franklin in a subdirectory named .visit/linux-x86_64/plugins/databases.

The installed files should look like this:

```

~/.visit/linux-x86_64/plugins/databases/

-rwx------ 1 user user  396846 Oct  5 14:07 libEVsDatabase_par.so

-rwx------ 1 user user 1880022 Oct  5 14:07 libEVsDatabase_ser.so

-rwx------ 1 user user   19548 Oct  5 14:07 libIVsDatabase.so

-rwx------ 1 user user 1880000 Oct  5 14:07 libMVsDatabase.so

```

**Installing plugin on local machine**

In order for your local copy of VisIt to know that the VizSchema plugin is available, it is necessary to install it on your local machine as well. Use the instructions here to do so. Note that you will need to compile the plugin for your local machine, as it is not currently distributed in binary form for most computers. 

**Configuring VisIt**

Follow the excellent instructions  [here](http://www.nersc.gov/nusers/resources/software/apps/visualization/visit/visit_franklin_remote.php) to configure your Franklin account and your local machine.