Running LAMMPS

From within the LAMMPS–GUI main window, LAMMPS can be started either from the Run menu by selecting the Run LAMMPS from Editor Buffer entry, using the keyboard shortcut Ctrl-Enter (Command-Enter on macOS), or by clicking the green Run button in the status bar. While LAMMPS is running, a message on the left side indicates that LAMMPS is active, along with the number of active threads. On the right side, a progress bar is displayed, showing the estimated progress of the current run or minimize command.

Creating Snapshot Images

Open the Image Viewer using either the Create Image option from the Run menu, the Ctrl-I keyboard shortcut, or click on the (right) palette button in the status bar. The image can be saved using the Save As... option from the File menu.

The Output Window

By default, when starting a run, the Output window opens to display the screen output of the running LAMMPS calculation. The text in the Output window is read-only and cannot be modified, but keyboard shortcuts for selecting and copying all or part of the text can be used to transfer it to another program: The keyboard shortcut Ctrl-S (or Command-S on macOS) can be used to save the Output buffer to a file. Additionally, the Select All and Copy functions, along with a Save Log to File option, are available through the context menu, which can be accessed by right-clicking within the text area of the Output window.

The Charts Window

By default, when starting a run, a Charts window opens to display a plot of the thermodynamic output from the LAMMPS calculation. From the File menu in the top-left corner, you can save an image of the currently displayed plot or export the data in various formats: plain text columns (for use with plotting tools like Gnuplot or XmGrace), CSV data (suitable for processing in Microsoft Excel, LibreOffice Calc, or Python with Pandas), or YAML (which can be imported into Python using PyYAML or Pandas). You can use the mouse to zoom in on the graph by holding the left button and dragging to select an area. To zoom out, right-click anywhere on the graph. You can reset the view by clicking the lens button located next to the data drop-down menu.

Preferences

The Preferences dialog allows customization of the behavior and appearance of LAMMPS–GUI. Among other options:

  • In the General Settings tab, the Data update interval setting allows you to define the time interval, in milliseconds, between data updates during a LAMMPS run. By default, the data for the Charts and Output windows is updated every 10 milliseconds. Set this to 100 milliseconds or more if LAMMPS–GUI consumes too many resources during a run. The Charts update interval controls the time interval between redrawing the plots in the Charts window, in milliseconds.

  • The Accelerators tab enables you to select an accelerator package for LAMMPS to use. Only settings supported by the LAMMPS library and local hardware are available. The Number of threads field allows you to set the maximum number of threads for accelerator packages that utilize threading.

  • The Editor Settings tab allows you to adjust the settings of the editor window. Select the Auto-save on Run and Quit option to automatically save changes made to the .lmp file upon closing LAMMPS–GUI.

See How-to LAMMPS--GUI for a full list of options.