Key error 'y' for from_pystan function

Hello,

I am new to Arviz. I was just trying to import PyStan model to Arviz by using “from_pystan” function but I get key error for ‘y’. I could not pass this initial step. Excuse me for this naive question.

eight_school_data = {
    'J': 8,
    'y': np.array([28., 8., -3., 7., -1., 1., 18., 12.]),
    'sigma': np.array([15., 10., 16., 11., 9., 11., 10., 18.])
}

stan_model = pystan.StanModel(model_code=schools_code)
fit = stan_model.sampling(chains=1, data=eight_school_data, control={"adapt_delta" : 0.9})

stan_data = az.from_pystan(
    posterior=fit,
    posterior_predictive='y_hat',
    observed_data=['y'],
    log_likelihood={'y': 'log_lik'},
    coords={'school': np.arange(eight_school_data['J'])},
    dims={
        'theta': ['school'],
        'y': ['school'],
        'log_lik': ['school'],
        'y_hat': ['school'],
        'theta_tilde': ['school']
    }
)

[maktukmak]

Hi Oriol, your solution for the latest release worked for me. Thanks.

[OriolAbril]

I think I know what is happening, the docs are for development version, not for latest release, and the option to use a dict as log_likelihood arg is only available in development version, there are two possible solutions.

I’d recommend installing the development version. The code should work, and log_likelihood group will be present like in cookbook.

Otherwise, use log_likelihood="log_lik" which will work with latest release. In this case there will be no log likelihood group, the data will be in sample stats.