stan_backend is missing when loading model from json

from fbprophet.serialize import model_to_json, model_from_json
with open("serialized_model.json", "r") as fin:
    fb_model = model_from_json(json.load(fin))

df_cv = cross_validation(fb_model, ............)

It produces this error,

File "C:\Users\XXXXX\.conda\envs\fbprophet7\lib\site-packages\fbprophet\diagnostics.py", line 295, in prophet_copy
    stan_backend=m.stan_backend.get_type()
AttributeError: 'NoneType' object has no attribute 'get_type'

Code snippet from diagnostics.py

m2 = m.__class__(
        growth=m.growth,
        n_changepoints=m.n_changepoints,
        changepoint_range=m.changepoint_range,
        changepoints=changepoints,
        yearly_seasonality=False,
        weekly_seasonality=False,
        daily_seasonality=False,
        holidays=m.holidays,
        seasonality_mode=m.seasonality_mode,
        seasonality_prior_scale=m.seasonality_prior_scale,
        changepoint_prior_scale=m.changepoint_prior_scale,
        holidays_prior_scale=m.holidays_prior_scale,
        mcmc_samples=m.mcmc_samples,
        interval_width=m.interval_width,
        uncertainty_samples=m.uncertainty_samples,
        stan_backend=m.stan_backend.get_type()
    )

It errors out when it tries to copy another model object I can comment out “stan_backend=m.stan_backend.get_type()” to make it work, not sure if it has any complication or raise any concern.

Can be easily replicated when you load a model from json, using FBProphet v0.7 on windows.

from fbprophet.serialize import model_to_json, model_from_json
with open('serialized_model.json', 'r') as fin:
    fb_model = model_from_json(json.load(fin))
fb_model.stan_backend.get_type()

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-104-5351aed8e4ed> in <module>
----> 1 fb_model.stan_backend.get_type()
 
AttributeError: 'NoneType' object has no attribute 'get_type'

[bletham]

The fix has been pushed to pypi in the new v1.0 (with the new package name, prophet)

[bletham]

This is fixed in eb6b8f6. Here is a test case:

import json
from fbprophet.serialize import model_from_json
from fbprophet.diagnostics import cross_validation


with open('serialized_model_v0.7.1.json', 'rb') as fin:
    model = model_from_json(json.load(fin))

df_cv = cross_validation(model, initial='15 days', horizon='1 day', period='2 days')  # Now works