[[PageOutline]] = VisIt = https://wci.llnl.gov/simulation/computer-codes/visit/ Visit Home Page] VisIt is an Open Source, interactive, scalable, visualization, animation and analysis tool. From Unix, Windows or Mac workstations, users can interactively visualize and analyze data ranging in scale from small (<10^1^ core) desktop-sized projects to large (>10^5^) leadership-class computing facility simulation campaigns. Users can quickly generate visualizations, animate them through time, manipulate them with a variety of operators and mathematical expressions, and save the resulting images and animations for presentations. VisIt contains a rich set of visualization features to enable users to view a wide variety of data including scalar and vector fields defined on two- and three-dimensional (2D and 3D) structured, adaptive and unstructured meshes. Owing to its customizable plugin design, VisIt is capable of visualizing data from over 120 different scientific data formats (see this [http://www.visitusers.org/index.php?title=Detailed_list_of_file_formats_VisIt_supports partial list]). == Introduction == === Installation === * You can download executables from [https://wci.llnl.gov/simulation/computer-codes/visit/downloads here]. * You can download the source code and compile it. They provides a script that automatically builds VisIt with all dependent libraries. == Execution Models == === Stand alone === * Basically, you install VisIt on your desktop (laptop) computer in front of you. And visualize data stored in the file system in your computer. * If you ran simulations on Cypress, you have to download the results data to the local computer with 'scp' or 'rsync' command. [[Image(StandAloneVisIt.png)]] === Server - Client System === * VisIt is able to visualize data stored in remote computers over the network. * You don't have to download the data into the local computer in order to visualize it. * For example: * Suppose you ran simulations on Cypress and stored results in the luster file system. * Run VisIt on the local computer and choose the remote file system when you open a data file. * VisIt program automatically runs on the remote computer and reads the data file. * You can work with VisIt as usual on the local computer. * Also you can use multiple nodes to render objects in parallel, which allow you to visualize a large data set. [[Image(ServerClientVisIt.png)]] * You must have same major version of VisIt on both local and remote computers. * Run "VisIt" on local machine and go to "Options" -> "Host profiles…" * Click [New Host] and edit like below: * Set ''Host nickname'' as you like. * ''Remote host name'' must be "cypress1.tulane.edu" or "cypress2.tulane.edu". * Set Path to visit installation. * Note that "/share/apps/visit/2.9.2" is where VisIt is installed on cypress. This may be changed in the future. Use "module avail" command to see which version is available on cypress. * The current version is 2.9.2 so you have to use visit 2.9.* on local machine. * Set ''Username''. This is your login ID for Cypress. * Check on ''Tunnel data connection through SSH'' * Click [Apply]. [[Image(VisItCypress1.png, 50%)]] ==== Serial Rendering ==== This set up VisIt to render objects with one process. * Select on [Launch Profile] tab. * Click [New Profile] and select [Setting] tab. Give a name on ''Profile name''. * Select [Parallel] tab and check ''Launch parallel engine''. * Select [Launch] tab and set '''srun''' on ''Parallel launch method''. * Set Numbers of processors and nodes 1. * Click [Apply]. [[Image(VisItCypressSerial.png, 50%)]] * After setup, do not forget to save : Go to "Options" -> "Save Settings". * Once setup and saved, you don't have do this again. ==== Parallel Rendering ==== This set up VisIt to render objects with multiple processes on multiple nodes. * Select on [Launch Profile] tab. * Click [New Profile] and select [Setting] tab. Give a name on ''Profile name''. * Select [Parallel] tab and check ''Launch parallel engine''. * Select [Launch] tab and set '''sbatch/mpirun''' on ''Parallel launch method''. * Set Number of processors, this is the total processors. * Set Number of nodes. * The example below sets Number of processors is 20 and Number of nodes is 2. This will use 2 nodes and 20 processes in total; 10 processes for each node. [[Image(VisItCypressParallel1.png, 50%)]] * Select [Advanced] tab. * Check ''Launcher arguments''. This is the parameters for SLURM queuing system. * In the example below, requesting 64G of RAM and 10 tasks (processes) per node. * Check ''Sublauncher pre-mpi command'' and set '''module load intel-psxe/2015-update1 visit'''. This is important to launch MPI tasks. [[Image(VisItCypressParallel2.png, 50%)]] * After setup, do not forget to save : Go to "Options" -> "Save Settings". * Once setup and saved, you don't have do this again. * To read data on cypress, "Open" and choose a Host, there must be "cypress" on the list. * You may be asked typing password every time you read data if you haven't set up passwordless ssh login.