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Reference documentation for deal.II version 9.6.0
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Namespaces | |
namespace | DataOutBase |
namespace | GridOutFlags |
deal.II generates three types of output: it can write triangulations/meshes in formats understood by several mesh readers (including those of deal.II itself), and it can create output used for visualization of data. Finally, it can output matrices in a graphical format.
deal.II supports, through the DataOutBase class, a large number of popular visualization formats, such as those used by the OpenDX, gmv, or gnuplot programs. A complete list of supported formats is listed in the documentation of the DataOutBase class.
The DataOutBase class is only responsible for actually writing some intermediate format in a number of different visualization formats. This intermediate format is generated by classes derived, directly or indirectly, from DataOutBase. For example, the DataOut class is most often used to generate this intermediate format from a triangulation, a DoFHandler object (that associates a particular finite element class with the triangulation), and one or more data vectors. The DataOut class creates intermediate data from each cell, which is subsequently written by the DataOutBase class in some final format. Almost all example programs, starting with step-3, make use of this method of generating output.
The DataOutFaces class is another way to create intermediate format from simulation data. However, instead of creating visualization data from each cell of the triangulation, it only creates information for all faces of cells that are located on the surface (though the class has a way to override the choice for which faces output should be generated). While this may not be particularly interesting in 2d (the faces would only be line segments) it is often helpful in 3d if what one really wants to know is the shape of the domain or the value of one variable on the surface. Using the DataOutFaces class then saves the effort of generating and storing data for all interior cells, which can be very expensive for large 3d simulations.
A third class, the DataOutRotation class, allows to take a two-dimensional simulation and generate three-dimensional data from it by rotating the two-dimensional domain around a given axis. This is mostly useful for the visualization of simulations that use the rotational symmetry of, for example, a cylinder.
Finally, the DataOutStack class allows to visualize data from time dependent simulations in the space-time domain: it collects the results from each time step and at the end outputs all of this information at once as a space-time file.
Meshes, without any data vectors associated with it, can be written in a number of formats as well. This is done through the GridOut class, and the documentation of that class lists the supported formats.
Several of the tutorial programs, notably step-1, step-6, step-9, step-10, and step-14 demonstrate the use of the GridOut class.
Through the MatrixOut class, deal.II can also give a graphical visualization of matrices, in the form of color or skyline plots. The MatrixOut class uses the DataOutBase for output. Therefore, matrices can be visualized in all formats supported by the latter class.