How to read data

Make sure the example data set exists in a directory you can access. Usually two files are needed, one in text format, called the description file, suffixed by desc in which you can read the name of format used and the name of the second file in which data is stored. Then call the executable VIGIE:

  $ vigie

The main window appears (see figure 1.1).

Figure 1.1: The VIGIE main window

Alternatively you can also call VIGIE with the name of a description file specified as one argument ; for example :

  $ vigie ex_2d.desc

If you choose to call VIGIE without argument, you can use the read data interface as follows :

• Push the button ``Files'' and select the menu ``Read data'' .
• A file selection box appears, (see figure 1.2). You can modify the filter name and push on the ``Filter'' button. When you show the desired file, a simple click on its name select the file, and a double click select it and allows to start reading of data as if you push on the ``OK'' button after the desired file has been selected.
• If the description file and the data file can be successfully read, the file selection box disappears and the data read is now the current solution of the current problem. You can obtain informations about the data if you push the ``Info'' button in the main window. Figure 1.3 is an example of such information window for a 2 blocks 3-D problem.

Figure 1.2: A File-Selection box to choose the data.

Figure 1.3: Information about data.

The information window indicates for each block defining the mesh:

• the block number.
• whether the block is structured or unstructured.
• the number of mesh nodes.
• the number of variables.
• how many element types (tetrahedra, hexahedra, prisms,...) the mesh contains.
• informations about the boundary.
• the dimension of the problem: 1D, 2D or 3D.

VIGIE includes the possibility te define fictitious boundaries to display particular values of interest to the user on these boundaries. Note that the variables located on the fictitious boundaries can be different from the ones located at the mesh nodes. If no fictitious boundary is provided, one is automatically computed, either there is the choice to compute a boundary different from the fictitious one specified by the user. For a structured block, it's the limits of the matrix; for unstructured blocks, segments (for 2D) or facets (for 3D) are computed. The boundary provided is often called the ``user frontier'', while the boundary computed is refered as the ``computed frontier''. For an unstructured block the ``computed frontier'' is created the first time this boundary is needed.


Note: You can read as many data as you want by clicking on ``Read data'' with the same VIGIE application, you can read and visualize 1-D, 2-D or 3-D data problems. You can load several solutions of the same problem and several problems with several solutions. In this case the main window (see figure 1.1) is modified (see figure 1.4) and you can use the ``SOLUTION'' option menu to select a solution of the current problem, and the ``PROBLEM'' option menu to change the current problem. The dimension push button ``1D'', ``2D'' or ``3D'' is sensitive for the dimension of the current problem.

Figure 1.4: The VIGIE main window with two problems.

Now you have read data, choose the chapter which corresponds to the dimension of your problem.