Issue with categorical parameters

[ophiry]

also posted in stack overflow: http://stackoverflow.com/questions/34599726/strange-error-when-using-optunity-maximize-structured-with-discrete-parameters

I'm trying to use optunity (version 1.1.1) for hyperparameter optimization
When I'm trying to use categorical parameters in the optimization, I get a strange crash.

I assume I don't define the categorical parameter correctly, though I follow the documetation

Code Example:

import pprint
import optunity

search_params = {
    'algorithm': {'algo1':
                      {'float1': [3, 9],
                       'float2': [0.3, 1.0],
                       'enum': {'val1': None, 'val1': None},
                       },
                  'algo2':
                      {'float3': [0.05, 0.15],
                       'float4': [3, 15],
                       }
                  }
}


def score_model(**kwargs):
    pprint.pprint(kwargs)
    return 0


optunity.maximize_structured(score_model, search_space=search_params, num_evals=20)

Output:

{'algo1': None,
 'algorithm': 'algo2',
 'float1': None,
 'float2': None,
 'float3': 0.13896484375,
 'float4': 9.12890625}
{'': 'enum',
 'algorithm': 'algo1',
 'float1': 5.162109375,
 'float2': 0.8612304687499999,
 'float3': None,
 'float4': None}
{'algo1': None,
 'algorithm': 'algo2',
 'float1': None,
 'float2': None,
 'float3': 0.06708984375,
 'float4': 8.75390625}
{'': 'float2',
 'algorithm': 'algo1',
 'float1': 3.662109375,
 'float2': 0.33623046874999996,
 'float3': None,
 'float4': None}
{'algo1': None,
 'algorithm': 'algo2',
 'float1': None,
 'float2': None,
 'float3': 0.09208984375,
 'float4': 11.75390625}

Note that some of the objects seem OK, and some contain a blank key

Error Message

Traceback (most recent call last):
  File "C:/dev/git/the_lab/relevancy_models_for_dentsply/optimize_models_alt.py", line 23, in <module>
    optunity.maximize_structured(score_model, search_space=search_params, num_evals=5)
  File "C:\dev\venv\lib\site-packages\optunity\api.py", line 370, in maximize_structured
    pmap=pmap, decoder=tree.decode)
  File "C:\dev\venv\lib\site-packages\optunity\api.py", line 266, in optimize
    call_dict = f.call_log.to_dict()
  File "C:\dev\venv\lib\site-packages\optunity\functions.py", line 232, in to_dict
    args[key].append(value)
KeyError: ''

[claesenm]

Thanks for reporting this problem, which at first glance seems to be an issue on our end, not yours. I will check this out ASAP.