Bug in `environmental_contours_example.mlx` due to `spectra_to_pandas` return variable

[MShabara]

Description:
The environmental_contours_example.mlx script relies on the energy_period.m and significant_wave_height.m functions, both of which call the py.mhkit_python_utils.pandas_dataframe.spectra_to_pandas function. There seems to be a bug in this example that causes it to take hours to run.

Steps to Reproduce:
1- Run the environmental_contours_example.mlx script.
2- Observe the execution time.
3- Check the return variable from py.mhkit_python_utils.pandas_dataframe.spectra_to_pandas.

Expected Behavior:
The script should execute within a reasonable timeframe.

Actual Behavior:
The script takes hours to complete execution due to an issue related to the spectra_to_pandas return variable.

[simmsa]

@MShabara, thanks for reporting this. I think I have a fix in PR #149 here

The underlying issue is how the NDBC spectra gets converted and passed to python. The linked typecast_spectra_to_mhkit_python is meant to explicitly handle this task and formats the input spectrum, either 2d or 1d into the correct format to create a pd.DataFrame that MHKiT-Python understands.

With the changes in #149 and this snippet below for section 2 I was able computer Hm0 and Te from the NDBC data:

% Get list of year fields
year_fields = fieldnames(ndbc_requested_data);

% Initialize as empty arrays - will grow dynamically
Hm0 = [];
Te = [];

% Process and concatenate each year
for i = 1:length(year_fields)
    fprintf('Processing %s\n', year_fields{i});
    
    S = struct();
    S.frequency = ndbc_requested_data.(year_fields{i}).frequency;
    S.spectrum = ndbc_requested_data.(year_fields{i}).spectrum;
    S.type = 'time series';
    
    % Concatenate results horizontally
    Hm0 = [Hm0, significant_wave_height(S)];
    Te = [Te, energy_period(S)];
end

I plan to revisit #113 and incorporate this change.

LMK if you see any issues with this potential solution.

[simmsa]

This code section section is used in a few of the WDRT example notebooks. The specific fixes are linked below:

• environmental_contours_example
• extreme_response_contour_example
• extreme_response_full_sea_state_example

These fixes will be included in the upcoming v0.6.0 release. @MShabara LMK if this fix is sufficient.