summary method of elfi.methods.results.Sample object throws NoneType error in Python interactive mode

[p-robot]

Summary:

As per the title, calling the summary method of elfi.methods.results.Sample object throws NoneType error in Python interactive mode

Description:

This is following the MA(2) model in the ELFI documentation.

Reproducible Steps:

import numpy as np
import scipy.stats

seed = 20170530
np.random.seed(seed)

def MA2(t1, t2, n_obs=100, batch_size=1, random_state=None):
    # Make inputs 2d arrays for numpy broadcasting with w
    t1 = np.asanyarray(t1).reshape((-1, 1))
    t2 = np.asanyarray(t2).reshape((-1, 1))
    random_state = random_state or np.random

    w = random_state.randn(batch_size, n_obs+2)  # i.i.d. sequence ~ N(0,1)
    x = w[:, 2:] + t1*w[:, 1:-1] + t2*w[:, :-2]
    return x

t1_true = 0.6; t2_true = 0.2
y_obs = MA2(t1_true, t2_true)


import elfi

t1 = elfi.Prior(scipy.stats.uniform, 0, 2)
t2 = elfi.Prior('uniform', 0, 2)

Y = elfi.Simulator(MA2, t1, t2, observed=y_obs)

def autocov(x, lag=1):
    C = np.mean(x[:,lag:] * x[:,:-lag], axis=1)
    return C

S1 = elfi.Summary(autocov, Y); S2 = elfi.Summary(autocov, Y, 2)

d = elfi.Distance('euclidean', S1, S2)
rej = elfi.Rejection(d, batch_size=10000, seed=seed)

result = rej.sample(1000, quantile=0.01)
result.summary()

Current Output:

In [2]: result.summary()
Method: Rejection
Number of posterior samples: 1000
Number of simulations: 100000
Threshold: 0.123
Posterior means: t1: 0.552, t2: 0.272

TypeError                                 Traceback (most recent call last)
<ipython-input-2-c942b82acb49> in <module>()
> 1 result.summary()

TypeError: 'NoneType' object is not callable

ELFI Version:

0.6.0

Python Version:

3.6.1

Operating System:

MacOSX 10.12.5

[vuolleko]

The automatic name inspection does not work in interactive Python shell, so you have to name the nodes manually:

t1 = elfi.Prior(scipy.stats.uniform, 0, 2, name='t1')
t2 = elfi.Prior('uniform', 0, 2, name='t2')
Y = elfi.Simulator(MA2, t1, t2, observed=y_obs, name='Y')

and so on.

Also, please update to ELFI 0.6.1, which gives a warning in this scenario.

[p-robot]

Excellent. I upgraded via github and now no error is thrown. Thanks very much!