Add OpenSEES

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Source OpenSEES
Use OpenSEES as main analysis program, and post-processing with python libraries. Here chatgpt comes to the picture to write some post-processing scripts. It wrote a script for to pipeline opensees analysis results to directly .vtk format so that we can open it with Paraview.

Here are the step-by-step instructions to pipeline OpenSEES analysis results to the .vtk format using a Python script:

1. Install OpenSEES and Python: Ensure that you have OpenSEES and Python installed on your system.
2. Create a new Python script: Open your preferred text editor or Python IDE and create a new script file.
3. Import necessary libraries: At the beginning of the script, import the required libraries:

   import os
   import subprocess

4. Define the OpenSEES command: Define the command to run the OpenSEES analysis. Replace your_analysis_script.tcl with the path to your OpenSEES analysis script.

   opensees_cmd = "opensees -file your_analysis_script.tcl"

5. Run the OpenSEES analysis: Use the subprocess module to run the OpenSEES command and save the output to a text file.

   subprocess.run(opensees_cmd, shell=True, stdout=open("output.txt", "w"))

6. Parse the OpenSEES output: Write a function to parse the OpenSEES output text file and extract the necessary data for the .vtk format.
7. Generate the .vtk file: Write a function to generate the .vtk file using the parsed data. Use the os module to specify the output file path and name.

   vtk_file_path = "output.vtk"
   with open(vtk_file_path, "w") as vtk_file:
       vtk_file.write("VTKFile\n")
       vtk_file.write("Type: UnstructuredGrid\n")
       vtk_file.write("Version: 0.1\n")
       vtk_file.write("ByteOrder: LittleEndian\n")
       vtk_file.write("DataMode: ASCII\n")
       vtk_file.write("NumberOfPoints: " + str(num_points) + "\n")
       vtk_file.write("Points\nfloat\n")
       # Write point coordinates here
       vtk_file.write("NumberOfCells: " + str(num_cells) + "\n")
       vtk_file.write("Cells\n" + str(num_cells) + " " + str(cell_type) + "\n")
       # Write cell connectivity and types here

8. Use Paraview to open the .vtk file