General Program Information for Gryphon

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General Program Operation

Requirements of the Program

    The only definite requirement for running Gryphon is a valid Java Runtime Environment, version 1.4.0 or higher. This piece of software is distributed free by Sun Microsystems, Inc. for many operating systems, and some less common OS manufacturers also provide Java free for their users. A list of download locations is available.

Accessing the Program

    Accessing the program can be done through the Gryphon applet page. There are serveral ways to start the program.
    The first method is the recommended method. This is the method utilizing the Java Web Start software, which is included in version 1.4 of the Java Software Developer Kit or Java Runtime Environment from Sun Microsystems. This software is distributed by Sun for Windows, Linux, and Solaris operating systems. Additionally, Mac has a version of Web Start for their Java Runtime Environment as well. As of version 1.4 (in Windows and Linux anyway), the Java Web Start product is included in a separate installation file in the "jre" directory of the Java installation directory. After installing the extra program, the software can be run by running "javaws.exe" in Windows or "javaws" in Linux in the installed folders. More detailed instructions may be found on the Web Start site on installing and running this software.
    Once Java Web Start is installed, it is a simple matter to select the link to start Gryphon for Java Web Start by selecting the link on the applet page. The first time this is done, depending on what browser is used, it may be necessary to associate the link on the web, which is to a JNLP file, to Java Web Start. The is called MIME type, and all browsers keep lists of what program to use to open a link of a certain extension. If a dialog appears asking what to do with the JNLP file type, select the option that the file should be opened with "javaws.exe" in Windows or "javaws" for Linux and Solaris. More details can be found in the particular browser documentation or in the Java Web Start documentation. This association should be automatic after the first time.
    The second method of running Gryphon involves running the code from the applet on the applet page. If Java 1.4 or higher is running on the system, a launch button appears. Clicking on the launch button on the screen starts a web version of Gryphon. Although this might seem easier than running Java Web Start at first, it is not the preferred method because running the code through a web applet places certain restictions on the code detailed just below.
    The third method available is that the bundle of class files are available to be downloaded and run using Java on the user's desktop. This is again not preferred because once the code is downloaded, the user has no way of knowing about updates and improvements to the code.
    Once the code is running through Java Web Start for the first time, the user will be promted with a dialog box saying that Gryphon is requesting unrestricted access to the local system. The code is self-signed using the included Java signing tool. The dialog will say that this signature cannot be verified because it has not been generated by any of the large computer security companies in the area. It is important to understand that there is no implied warranties or guarantees in using Gryphon, and any use of or effects on the computer is completely the responsibility of the user. However, with this said, Gryphon requires access only to read and write files to the user's local hard drive. It makes no other changes to the local system if the user says "Yes" to this security dialog. These files are only for saving the database and solution information that the user generates for a future session. After agreeing to the unlimited security option once, this dialog is never repeated again.
    If the user denies access, or if the user runs the code through the applet discussed above, Gryphon cannot read or write files. The code still runs and still solves problems, but there is no record to save from session to session, and all information will be lost when the user shuts off the program.
    It is also important to understand that downloading and running the application locally from the hard drive inherantly has the same security risks that running a code unrestricted through Web Start does. Additionally, Web Start automatically updates the application whenever a new version is available. Therefore, Web Start is the preferred method of running Gryphon. Once the code has been downloaded once, the application can be run either from the Gryphon applet web page or from starting Web Start locally from the desktop (the "javaws.exe" or "javaws" files) and selecting Gryphon from the window which appears.

Basics of the Interface

    Once the program is running, the graphical user interface will appear. Thanks to Java's design, this window will appear similar in any operating system that supports it. The window will take on the characteristic fonts and borders of the system, but one should see a window which looks like the main window shown below in Figure 1. That particular screenshot was taken in Linux Redhat 7.3.

(click this image to enlarge)
Figure 1. Main GUI Window of Gryphon with Highlighted Areas

The interfacing consists primarily of several main features.

The main window title bar in Gryphon shows the program name, the program revision number, and the current file name that is open. Initially, Gryphon opens a new file, which is always titled "Untitled". Depending on the operating system, the look of the title bar and border will vary, but most OS's usually have a basic system menu for closing, minimizing, etc.
The main menu does all the basic input and output of files and data to the code. Currently, there are several menus to choose from. A closer view of this menu is given in Figure 2. It is discussed in detail below.

Figure 2. Close-up View of Main System Menu and Tabbed Navigation Areas
The main navigation tabs are the key to operating the code and doing something useful with it. The main menu has been reserved for general input/output type operations that typically require a lot of dialog boxes and such things. The navigation tabs are provided for quicker convenience without having to traverse through a lot of dialog boxes. A closer view of the navigation area is also shown above in Figure 2. There are four tabs, corresponding to the four main steps of the code. In general, one builds a model by moving from left to right in the tabs (although you can certainly select any tab at any time). These four tabs are:

Model: information and options for generating the physical model and grid
BC: information and options for setting the boundary conditions and initial conditions
Solution: solution options and solution control and well as the "Solve" button
Graph: post-processing options for looking at the grid and/or solution via graphical means in the two graphing windows

The line graph window is a primary tool for looking at the solution results. Up to three curves can be graphed at once. Any quantity of interest can be graphed, and the window may graph these selected variables as a function of spatial position or time. Residuals may also be plotted as a function of iteration number. More detail on the line graph control will be given in the Graphing Options section.
Like the line graph, the contour window is a primary tool for looking at solution. When initially opened, the contour window shows the physical model. After the grid has been generated or an existing file opened, the grid will be shown. If the line graph is plotting a value as a function of spatial coordinate, x, the contour window may optionally be selected to draw colorful surface contours on the grid that corresponds to the first line graph. This provides an alternate, visually friendly way to interprete data. The gridlines may be eliminated to better view the contours. More will be covered on controlling the contour window in the Graphing Options section as well.

Navigating the Main Menu

The main menu offers many general features which will be discussed here, such as file control. Some of the more specific menu features will be discussed in later sections where they are more applicable. Before talking in detail about them, detailed views of the various menus are shown in Figure 3.

(a) File Menu

(b) Grid Menu

(d) Options Menu

(e) Help Menu

Figure 3. Detailed View of Individual Main System Menus

The file menu contains many of the usual graphical program options that are found in most programs. It also contains two submenus: Import and Export. These two submenus are shown in expanded form in Figure 4.

(a) Import Submenu

(b) Export Submenu

Figure 4. Detailed View of Individual Submenus of the File Menu

The contents of the file menu (Fig. 3a) are listed here with descriptions for convenience:

New: This option opens a new, blank physical model with which to build a new grid. Any existing physical model and/or grid are deleted.
Open: This option restores a previously saves file containing physical model, grid database, solution options, and solution data. Opening a file provides a complete restoration of the previous data at the point of save. By default , Gryphon saves files with an .egd extension. This extension can be overridden. Gryphon opens a standard, common, system dependent open dialog box to accomplish this task.
Save: This option provides a complete save point, storing physical model, grid information, solution options, boundary condition data, and solution data. The previous save point in the file is completely overridden. Gryphon uses built in zip compression to minimize required storage space. By default, the file used to save the data contains a .egd extension. If the database has yet to be named, i.e. is still "Untitled," a standard system save file dialog box is provided to pick and specify a file name. After the name is specified once, save always overwrites the same file.
Save As: This option is used like the Save option to provide a complete restore point. A standard save file dialog box opens allowing the user to specify a new file name for the opened database rather than overwriting the old file with the Save command. This is useful to provide several restore points is one is unsure about the outcome of a calculation. Once this command has been executed, the default file name is changed permantently, and subsequent save commands will overwrite the newly specified file name. The old file must be re-opened to use it again.
Import/Import Plain Text: Importing plain text refers to importing a grid from a plain text file. This is a file which might have been generated in another program by some means. Details of the requirements for this file will be given later in the section on creating a grid, but this file must be a two column ASCII text file separated by spaces or tabs with pairs of numbers consisting of position and area [x A]. A dialog box opens which allows the user to graphically select the text file. Once this command is successfully executed, the grid is created directly from the file, bypassing the physical model. For this case, there is no physical model at all.
Import/Import Copied Text: Importing copied text has similar requirements and results as the above import of plain text. Here, however, the command brings up a dialog box with a large text window. The idea is that points consisting of pairs of position and area values may be types in by hand or , more likely, pasted using the system clipboard from another program. Just as in the plain text file case, Gryphon uses this feature to directly build a grid without he presence of a physical model.
Export/Export Plain Text: Exporting a plain text file results in a tab delimited file which conforms to the standards required for importing a plain text grid file. A system save file dialog box opens which allows the user to graphically enter the desired file and save location. This command saves a text file of the position and grid points only -- it does NOT save any physical model data or solution data at all. This option is useful for importing the grid into some other type of program.
Exit: This command exits Gryphon.

    The Grid menu (Fig 3b) will be discussed in more detail in the sections on creating a physical model and creating a grid. The various option commands in the menu will be described fully there. The grid menu will be most often used in conjunction with the first navigation tab, the Model tab.
    The Solution menu (Fig. 3c) has various commands for controlling the storage of solution data. Detailed discussion of these commands will appear under several later sections. The Solution menu includes provisions for initializing and removing the solution, managing the solution for time dependent problems where there may be many time levels stored and the user wishes to eliminate some ofthe intermediate steps, and a system for listing the data. This list dialog box in particular is another important solution evaluation tool and provides a way to copy or save data for export to another post-processing program. The Solution menu will most often be used with the third and forth navigation tabs -- the Solution and Graph tabs.
    The Options menu (Fig 3d) has miscellaneous commands for doing various things in the program. These options may be used at almost any point in the program execution, and will be discussed as they are most appropriate. In particular, the Fluid Properties command opens a dialog box for setting the global fluid parameters of specific heat ratio and fluid gas constant. These two properties are independent of the geometry and problem type, but impact the solution. They must be known for the fluid of interest. Both must be positive, and the specific heat ratio must be larger than one. Also, the image capture submenu allows either the upper graph window (the line graph) or the lower graph window (the contour graph) to be saved to a picture file. Standard output options for JPEG and PNG format are allowed. The images saved will be the same number of pixels as the window shown on the screen. A tab in the Program Options dialog allows the amount of JPG compression to be controlled. For the contour window, both image formats provide good quality. Due to the nature of the image for the line graph and the algorithm for the JPG compression, that format shows typically some color degradation on the lines of the top window. For this window, PNG format is recommended, although both formats are certainly readable.
    The help menu (Fig. 3e) contains a command for diaplaying a typical "About" dialog box, containing version information, system nformation, program information, etc. This is typical of most graphically oriented programs.

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