Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

Weird xarray error after completing backtest. [BUG]

See original GitHub issue

Unfortunately, I have another bug that has arisen. Although I do not know if it is related. After running backtest code.

backtest_series = model.historical_forecasts(
    series=series_transformed,
    start=series_transformed.get_timestamp_at_point(0.9995),
    # Split data 60 train / 40 validate-test --- value
    forecast_horizon=7,
    stride=5,
    retrain=False,
    num_samples=1, 
    verbose=True
)

An error occurs after predicting the entire specified length occurs

ValueError                                Traceback (most recent call last)
/tmp/ipykernel_2006/609873824.py in <module>
      7     retrain=False,
      8     num_samples=1,
----> 9     verbose=True
     10 )
     11 print(backtest_series)

/pdrive/dt-env/lib/python3.7/site-packages/darts/utils/utils.py in sanitized_method(self, *args, **kwargs)
    170 
    171                 getattr(self, sanity_check_method)(*only_args.values(), **only_kwargs)
--> 172             return method_to_sanitize(self, *only_args.values(), **only_kwargs)
    173 
    174         return sanitized_method

/pdrive/dt-env/lib/python3.7/site-packages/darts/models/forecasting/forecasting_model.py in historical_forecasts(self, series, past_covariates, future_covariates, num_samples, start, forecast_horizon, stride, retrain, overlap_end, last_points_only, verbose)
    443                         step=1,
    444                     ),
--> 445                     np.array(last_points_values),
    446                 )
    447 

/pdrive/dt-env/lib/python3.7/site-packages/darts/timeseries.py in from_times_and_values(cls, times, values, fill_missing_dates, freq, columns, fillna_value)
    604             coords[DIMS[1]] = columns
    605 
--> 606         xa = xr.DataArray(values, dims=(times_name,) + DIMS[-2:], coords=coords)
    607 
    608         return cls.from_xarray(

/pdrive/dt-env/lib/python3.7/site-packages/xarray/core/dataarray.py in __init__(self, data, coords, dims, name, attrs, indexes, fastpath)
    404             data = _check_data_shape(data, coords, dims)
    405             data = as_compatible_data(data)
--> 406             coords, dims = _infer_coords_and_dims(data.shape, coords, dims)
    407             variable = Variable(dims, data, attrs, fastpath=True)
    408             indexes = dict(

/pdrive/dt-env/lib/python3.7/site-packages/xarray/core/dataarray.py in _infer_coords_and_dims(shape, coords, dims)
    153             if s != sizes[d]:
    154                 raise ValueError(
--> 155                     f"conflicting sizes for dimension {d!r}: "
    156                     f"length {sizes[d]} on the data but length {s} on "
    157                     f"coordinate {k!r}"

ValueError: conflicting sizes for dimension 'time': length 972 on the data but length 4856 on coordinate 'time'

_Originally posted by @Joe-TheBro in https://github.com/unit8co/darts/issues/814#issuecomment-1049543735_