ACF calculation 'division by zero' bugfix

[AviadAvr]

Short Description

Calculating the autocorrelation function of certain timeseries raises the division by zero error.
The error arises when a timeseries of hourly frequency and equidistant timesteps is analyzed.
Hourly frequency causes the dt_mu variable to be <1, which when converted to an int returns 0.
This only triggers if the timesteps can be inferred:

    if x.index.inferred_freq and y.index.inferred_freq:
        bin_method = "regular"
 ...
    if isinstance(lags, int) and bin_method == "regular":
        lags = arange(int(dt_mu), lags + 1, int(dt_mu), dtype=float)

The testing functions were also updated to include a scenario where the timesteps are of hourly frequency and where no lags are provided (and are therefore type(lags)==int).

Checklist before PR can be merged:

• closes issue #771
• is documented
• Format code with Black formatting
• type hints for functions and methods
• tests added / passed
• Example Notebook (for new features)
• Remove output for all notebooks with changes

[raoulcollenteur]

Hi @AviadAvr, Thanks for the PR, looks good! Quick question before merging. Could you open another issue with a feature request to adapt the ACF function to work on hourly data? Then we keep track of all new features for the next release :)

Cheers
Raoul

[AviadAvr]

Hi @AviadAvr, Thanks for the PR, looks good! Quick question before merging. Could you open another issue with a feature request to adapt the ACF function to work on hourly data? Then we keep track of all new features for the next release :)

Cheers Raoul

Hey @raoulcollenteur, anything specific in mind that needs to be updated in the ACF function regarding hourly data?

[raoulcollenteur]

Hi @AviadAvr, Thanks for the PR, looks good! Quick question before merging. Could you open another issue with a feature request to adapt the ACF function to work on hourly data? Then we keep track of all new features for the next release :)
Cheers Raoul

Hey @raoulcollenteur, anything specific in mind that needs to be updated in the ACF function regarding hourly data?

No nothing specific, but I thought you also fixed an issue for hourly data or not? Otherwise I'll just merge this.