Learning Forum

[Bob]

The script below is a Python code embedded in Ansys Mechanical. After the analysis is performed, the results of each step are intended to be saved into a JSON file.

import json

def after_post(this, solution): # Do not edit this line
    print("post script")
    mesh = DataModel.MeshDataByName(ExtAPI.DataModel.MeshDataNames[0])
    solution = Model.Analyses[0].Solution
    
    node_count = mesh.NodeCount
    
    aset = Model.Analyses[0].AnalysisSettings
    steps = aset.NumberOfSteps
    
    solution = Model.Analyses[0].Solution
    base_dir = "C:\\temp\\"
    
    data = {}
    
    for step in range(steps):  # steps
        time = aset.GetStepEndTime(step + 1)
    
        for obj in solution.Children:
            name = obj.Name
            if name in ["LOCX", "LOCY", "LOCZ", "UX", "UY", "UZ"]:
                obj.DisplayTime = time
                
        solution.EvaluateAllResults()
        
        timestep_data = []
        
        LOCX = DataModel.GetObjectsByName("LOCX")[0].PlotData
        LOCY = DataModel.GetObjectsByName("LOCY")[0].PlotData
        LOCZ = DataModel.GetObjectsByName("LOCZ")[0].PlotData
        UX = DataModel.GetObjectsByName("UX")[0].PlotData
        UY = DataModel.GetObjectsByName("UY")[0].PlotData
        UZ = DataModel.GetObjectsByName("UZ")[0].PlotData
        
        for i in range(len(LOCX['Node'])):
            node_data = [
                LOCX["Values"][i],
                LOCY["Values"][i],
                LOCZ["Values"][i],
                UX["Values"][i],
                UY["Values"][i],
                UZ["Values"][i]
            ]
            timestep_data.append(node_data)
        
        data[str(step + 1)] = timestep_data
    
    sorted_data = {k: data[k] for k in sorted(data)}
    json_file_path = base_dir + "example.json"
    with open(json_file_path, 'w') as json_file:
        json.dump(sorted_data, json_file, indent=4)

    print("Data saved to", json_file_path)
    pass

When solving this simulation, the following error occurs. The very strange thing is that when solving the exact same file 10 times, this error occurs about 8 times, while it runs successfully about 2 times. We have not yet identified the cause. Your help is urgently needed!

 

Error

Error when invoking function 'after_post'.Traceback (most recent call last):
File "", line 30, in after_post
StandardError: Exception has been thrown by the target of an invocation.Traceback (most recent call last):
File "", line 30, in after_post
NotImplementedError: PlotData is not supported for LOCX

Python Code "Python Code" (Object ID 721) execution aborted: recursive execution has been detected. This is typically caused by an "update" or "evaluate" command. Please 1) verify the code correctness, and 2) ensure the correct callback is being used.

An error occurred when the post processor attempted to load a specific result. Please review all messages.

[mjmiddle]

You shouldn't be using the following in an after_post callback:

solution.EvaluateAllResults()

This would evaluate results again which would run after_post again and get you stuck in an endless loop. The after_post callback is done immediately after all native results are evaluated, so there is no need to call this in your script anyway. All native results will be up-to-date at the time of this after_post callback.