EZyRB

Tutorial 3: Use of the Graphic Unit Interface (GUI)

In this tutorial we will show the typical workflow for the model order reduction using the GUI. Basically, go to the EZyRB main directory, open the terminal and type:

> python start_gui.py

The command opens the graphic unit interface, like the one in figure

We will focus first on the offline step, where we build the POD basis.

Offline step

Let us now set all the parameters we need for the problem at hand (the same as Tutorial 1 and Tutorial 2):

• the output files we want to use are stored in the directory tests/test_datasets with prefix matlab_0. Thus, in the first line, we write tests/test_datasets/matlab_0
• the name of the weights for each value of the output (that we exploit for the computation of the errors) is simply Weights. Thus, in the second line we write Weights
• The output of interest is the pressure field. In the matlab_0*.vtk the pressure field is named Pressure, so we just type Pressure in the third line
• as already mentioned, the output is a field and it is stored in a vtk file, so we tick Field and .vtk in the fourth and fifth line, respectively.

The GUI should appear as

Let us now start the algorithm by pressing on the start EZyRB button. Just below, the code suggest the new parameter values and the error estimation with the present database.

Once we compute the output of interest with the new parameter value suggested, stored in the proper directory with the proper name (the same as Path and Prefix with increasing numeration) we can press the Enrich button. With a new output added to the database, the code suggest the new parameter values and the error estimation.

We end the algorithm by pressing the Finish button. In this way we write out the structures we need for the online step.

Online step

Let us now focus on the right part of the GUI:

• we need to load the triangulation of the parameter space for the interpolation of the coefficients for the pod basis. Press on Pick triangulation and chose the correct file, that is, coefs_tria_Pressure.npy
• of course, we need also to load the pod basis. Press on Pick pod basis and chose the correct file, that is, pod_basis_Pressure.npy
• Output of interest is already set equal to the one of the Offline step. If you open the GUI only for the online step, we need to set the output name here.
• the same procedures is valid for Output is a and Select file format
• in order to write the new evaluation of the corresponding geometry, we need also to select a file containing the right geometry. Thus, we click on File for parsing and select the file containing (among other stuff) the proper geometry (tests/test_datasets/matlab_online_test.vtk in this case)
• now we insert the new parameter values. Each value of the parameters must be separated by a comma
• finally, we set the name of the new output file.

When all the variables are set, just click on Start EZyRB button and this is it!

When the algorithm ends its routines, it prints out a finish message on the bottom. The result looks like the one depicted in figure.