Error querying parameters from Fluent session

[tejalprabhu01]

🔍 Before submitting the issue

• I have searched among the existing issues
• I am using a Python virtual environment

🐞 Description of the bug

Following error is seen on querying parameters from Fluent session using pyfluent from Ansys CPython. It is reproducible with all case files. This used to work with older version of pyfluent.

fluent_input_table = self.fluent_session.settings.parameters.input_parameters.list()
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1811, in call
return self.execute_command(**kwds)
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1748, in execute_command
ret = self._execute_command(*args, **scmKwds)
File "C:\Program Files/ANSYS
Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1729, in _execute_command
ret = _fix_parameter_list_return(ret)
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1781, in _fix_parameter_list_return
if len(units) > 0 and isinstance(units[0], str):
KeyError: 0

@seanpearsonuk @mkundu1

📝 Steps to reproduce

session = pyfluent.launch_fluent(start_watchdog=False)
session.settings.parameters.input_parameters.list()

💻 Which operating system are you using?

Windows

📀 Which ANSYS version are you using?

26.1

🐍 Which Python version are you using?

3.10

📦 Installed packages

ansys-fluent-core 0.33.0

[mkundu1]

The original settings API method now returns parameter units with the values. Below is the parser code to extract the parameters values and units:

import ansys.fluent.core as pyfluent
solver = pyfluent.launch_fluent()
solver.settings.file.read_case_data(file_name="elbow_param.cas.h5")
fluent_parameters = solver.settings.parameters.output_parameters.list()
assert fluent_parameters == {'outlet_temp-op': [322.3360076327903, {'temperature': ['k', 1.0, 0.0, 'K']}]}

pyfluent_parameter_values = {}
pyfluent_parameter_units = {}
for k, v in fluent_parameters.items():
    # Extract the value of the parameter
    pyfluent_parameter_values[k] = v[0]

    # Extract the unit of the parameter with defensive checks
    #  in case the structure is different for some edge cases
    if (isinstance(v, list) 
    and len(v) > 1
    and isinstance(v[1], dict)
    and len(v[1].values()) > 0
    and isinstance(list(v[1].values())[0], list)
    and len(list(v[1].values())[0]) > 0):
        pyfluent_parameter_units[k] = list(v[1].values())[0][-1]
    else:
        pyfluent_parameter_units[k] = ""

assert pyfluent_parameter_values == {'outlet_temp-op': 322.3360076327903}
assert pyfluent_parameter_units == {'outlet_temp-op': 'K'}

[tejalprabhu01]

The original settings API method now returns parameter units with the values. Below is the parser code to extract the parameters values and units:

import ansys.fluent.core as pyfluent
solver = pyfluent.launch_fluent()
solver.settings.file.read_case_data(file_name="elbow_param.cas.h5")
fluent_parameters = solver.settings.parameters.output_parameters.list()
assert fluent_parameters == {'outlet_temp-op': [322.3360076327903, {'temperature': ['k', 1.0, 0.0, 'K']}]}

pyfluent_parameter_values = {}
pyfluent_parameter_units = {}
for k, v in fluent_parameters.items():
    # Extract the value of the parameter
    pyfluent_parameter_values[k] = v[0]

    # Extract the unit of the parameter with defensive checks
    #  in case the structure is different for some edge cases
    if (isinstance(v, list) 
    and len(v) > 1
    and isinstance(v[1], dict)
    and len(v[1].values()) > 0
    and isinstance(list(v[1].values())[0], list)
    and len(list(v[1].values())[0]) > 0):
        pyfluent_parameter_units[k] = list(v[1].values())[0][-1]
    else:
        pyfluent_parameter_units[k] = ""

assert pyfluent_parameter_values == {'outlet_temp-op': 322.3360076327903}
assert pyfluent_parameter_units == {'outlet_temp-op': 'K'}

@mkundu1 not really.

On calling solver.settings.parameters.output_parameters.list(), I get following error

[ERROR] : 0
Traceback (most recent call last):
File "D:\ansysdev/sandbox2/Protos/optiSLang/scripting/integrations\Fluent\integration_base.py", line 619, in solve_case_designs
design.verified_parameter_values = self.session.get_calculation_parameters()
File "D:\ansysdev/sandbox2/Protos/optiSLang/scripting/integrations\Fluent\pyfluent_wrapper.py", line 351, in get_calculation_parameters
fluent_input_table = self.fluent_session.settings.parameters.input_parameters.list()
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1811, in call
return self.execute_command(**kwds)
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1748, in execute_command
ret = self._execute_command(*args, **scmKwds)
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1729, in _execute_command
ret = _fix_parameter_list_return(ret)
File "C:\Program Files/ANSYS Inc/v261\commonfiles\CPython\3_10\winx64\Release\Ansys\PyFluentCore\ansys\fluent\core\solver\flobject.py", line 1781, in _fix_parameter_list_return
if len(units) > 0 and isinstance(units[0], str):
KeyError: 0

I could fix it by overwriting _fix_parameter_list_return as follows:

def _fix_parameter_list_return(val): return val flobject._fix_parameter_list_return = _fix_parameter_list_return

I get following response
{'inlet_pressure': [93910.78666178207, {'density*specific-energy': ['j/m3', 1.0, 0.0, 'J m^-3'], 'force-per-area': ['n/m2', 1.0, 0.0, 'N m^-2'], 'pressure': ['atm', 101325.0, 0.0, 'atm'], 'source-turbulent-viscosity': ['kg/s2-m', 1.0, 0.0, 'kg m^-1 s^-2']}]}

I think _fix_parameter_list_return() in pyfluent seems to be broken

[mkundu1]

@tejalprabhu01 Sorry, forgot to mention taht this will need the PyFluent main branch where the function _fix_parameter_list_return() has been removed for 26.1. We'll create a new release with this change soon.

In older releases you can set the env var PYFLUENT_NO_FIX_PARAMETER_LIST_RETURN=1 to avoid the _fix_parameter_list_return() call.