metrics fails to execute on iAWE data set

[nipunbatra]

The HDF5 file can be downloaded from here:https://copy.com/C2sIt1UfDx1mfPlC

Here is the minimal code to reproduce the error.

from nilmtk import DataSet
from nilmtk.disaggregate import CombinatorialOptimisation
from nilmtk.metrics import fraction_energy_assigned_correctly
from nilmtk import HDFDataStore
source = "/Users/nipunbatra/Copy/Dataset/iawe.h5"
train = DataSet(source)
test = DataSet(source)
train.set_window(start='2013-05-24 00:00:00', end='2013-08-21 00:00:00')
train_elec = train.buildings[1].elec
co = CombinatorialOptimisation()
co.train(train_elec)
test.set_window(start="14-07-2013 00:00:00", end="27-7-2013 00:00:00")
test_mains = test.buildings[1].elec.mains()

disagout = "/Users/nipunbatra/Desktop/out.h5"
output = HDFDataStore(disagout, 'w')

co.disaggregate(test_mains, output)
output.close()
disag = DataSet(disagout)
disag_elec = disag.buildings[1].elec
fr = disag_elec['fridge'].load().next()
fr.head()

In [49]: fr.head()
Out[49]: 
                           power
                          active
2013-07-14 00:00:00+05:30     84
2013-07-14 00:01:00+05:30    121
2013-07-14 00:02:00+05:30      0
2013-07-14 00:03:00+05:30    121
2013-07-14 00:04:00+05:30     84

test_elec = test.buildings[1].elec
fr_pr = test_elec['fridge'].load().next()
fr_pr.head()

physical_quantity              power                      
type                        apparent     active   reactive
2013-07-14 00:00:00+05:30  92.081001  78.424004  48.255001
2013-07-14 00:00:01+05:30  91.843002  78.287003  48.023998
2013-07-14 00:00:02+05:30  92.055000  78.383003  48.271999
2013-07-14 00:00:03+05:30  91.543999  78.146004  47.893002
2013-07-14 00:00:04+05:30  91.834999  78.124001  48.196999

from nilmtk.metrics import mean_normalized_error_power
mean_normalized_error_power(disag_elec, test_elec)

In [55]: mean_normalized_error_power(disag_elec, test_elec)
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-55-a2cf9d5e8e93> in <module>()
----> 1 mean_normalized_error_power(disag_elec, test_elec)

/Users/nipunbatra/git/nilmtk/nilmtk/metrics.pyc in mean_normalized_error_power(predictions, ground_truth)
    145             sum_of_ground_truth_power += aligned_meters_chunk.icol(1).sum()
    146 
--> 147         mne[pred_meter.instance()] = total_abs_diff / sum_of_ground_truth_power
    148 
    149     return pd.Series(mne)

ZeroDivisionError: float division by zero

In [64]: f = fraction_energy_assigned_correctly(disag_elec, test_elec)
10/10 ElecMeter(instance=12, building=1, dataset='iAWE', appliances=[Appliance(type='motor', instance=1)])ce=1)]))r', instance=1)])ce=1)]))
In [65]: f
Out[65]: nan