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ELI

ELI is a graphical, numerical tool for exploring the solutions of the Riemann initial-value problem for a system of conservation laws

\[\begin{equation} G(U)_t + F(U)_x = 0 \label{eq:consLaw} \end{equation}\]

in one space and one time dimension. For a Riemann problem, the initial values take the form

\[\begin{equation} U(x, 0) = \begin{cases} U_L & \text{for $x < 0$,} \\ U_R & \text{for $x > 0$.} \end{cases} \label{eq:RP} \end{equation}\]

We seek scale-invariant solutions and allow for jump discontinuities (shock waves). A shock wave is required to be the limit, as \(\epsilon \to 0^+\), of a traveling wave solution of a system of diffusive conservation laws

\[\begin{equation} G(U)_t + F(U)_x = \epsilon \left[ B(U)\,K(U)_x \right]_x. \label{eq:viscosity} \end{equation}\]

An ELI model is an implementation of a particular choice for the

  • flux \(F(U)\),

  • accumulation \(G(U)\), and

  • diffusive flux \(B(U)\,K(U)_x\),

which are usually controlled by choosing values for several model parameters. Several models are implemented, including

  • quad in the Theory group of models,

  • corey_quad in the ThreePhase group of models,

  • surf in the Chem group of models,

  • micellar in the ThreePhase group of models.

GUI elements on tabs

The Main tab is the starting point for every construction in ELI. It contains tools such as buttons, toggles, choices, text and number input boxes. Several types of GUI elements appear on this (and every other) tab:

  • Result button: Button that executes calculations and shows result graphically without additional user input.

  • Listener button: Button that requires input coordinates, which can be specified by a mouse click in a graphical window or by typing into numbers into text input boxes.

  • Toggle tool: GUI element that allows select many of several binary options. It appears as a horizontal list of words. Such a tool is commonly found in a settings section.

  • Choice tool: GUI element that allows one to choose among several options. It appears as a vertical list of keywords. In contrast to Toggle tools, only one keyword can be chosen. Such a tool is commonly found in a settings section.

  • Text input box: GUI element into which text is entered. The text typed into the box is submitted when the Enter key is typed. Some such boxes maintain a memory of previous entries, which can be accessed using the Up and Down arrow keys. A previous entry is submitted, after possible modifications, when the Enter key is typed.

  • Number input box: GUI element into which a number is entered. The number typed into the box is submitted when the Enter key is typed. Sometimes such boxes are grouped; an example is the boxes for entering the components of a vector. For such a group, the entries in all boxes are submitted when the Enter key is typed in any of the boxes.

  • Panel opener button: GUI button with a name ending in .... Clicking the button opens a separate panel, which displays information or has its own GUI elements.

  • Command modifier: GUI button with a name ending in ->. Clicking on the button modifies the meaning of the next button that is clicked. For example, clicking on the Closest Point-> button and then on the Hugoniot button executes the Hugoniot Closest Point command.

GUI elements common to many tabs

  • Quit: Quit ELI.

  • Help...: Display the help file associated with this tab.

  • Info: Information from ELI is displayed. Examples include (a) the command invoked most recently and (b) warning messages.

Main Tab

The Main tab has the following GUI elements:

  • Input filename: Set the path to the current input file to the contents of the text box. The path can be absolute or relative to the directory where ELI was invoked.

An extensive set of input files is available for several ELI models. These files are found in the ELI/run/in/<model>/ directory. For instance, for the corey_quad model, this directory contains subdirectories such as demo/ and t/ containing input files for demonstration and testing.

  • Choose...: Open a file browser for selecting the input file.

  • Read: Read from the input file. Commands in the input file will be executed in sequence until a Pause command, a Quit command, or the end of the input file is encountered.

  • Command: Execute the ELI command typed into the text box. The format for the command is the same as in an input file. Note: ELI commands are usually executed by clicking GUI buttons, but this text box provides an alternative that is occasionally useful.

  • Put Pause:

  • Label Text:

  • Label:

  • Select State:

  • Input Mode:

  • state and speed number input boxes:

  • Closest Point->:

Environment

The current version of ELI does have a directory named construction that contains various construction files. This directory is now located inside the ELI/run directory. The ELI/run directory is intended to be the preferred launch point for an ELI model. It contains the in directory, the help directory, shell scripts for testing ELI, Python scripts for running ELI as a server, etc., along with the construction directory. The whole run directory (excluding output files) is installed in the AppImage for each ELI model. When an AppImage is run, the contents of run are installed (or brought up to date) in ~/ELI.home; then the AppImage changes to the ELI.home directory and invokes the ELI executable. There is also a Constructions tab on ELI's GUI, but it currently consists of only two command buttons. I don't know whether other command buttons or settings widgets should be added.

TODO: The following is for TESTING only.

Remove it as soon as possible.

  • Test of an internal link GUI elements on tabs.

  • Another test of an interal link [GUI elements common to many tabs][]: it works using pandoc but fails using scidown (which is necessary for Markdown files containing LaTeX, such as the present file).

  • Test of an external link:

    Fundamental Curves

  • Check whether LaTeX cross references work: Eq.\(~(\ref{eq:consLaw})\)

  • You have been hacked by the Stolem Wedge