Source code for aggregations

"""
Has the built-in aggregation functions, code for using them,
and code for adding new user-defined ones.
"""

import sys
import types
import warnings

from operator import mul

from neat.math_util import mean, median2

if sys.version_info[0] > 2:
    from functools import reduce


[docs]def product_aggregation(x): # note: `x` is a list or other iterable return reduce(mul, x, 1.0)
[docs]def sum_aggregation(x): return sum(x)
[docs]def max_aggregation(x): return max(x)
[docs]def min_aggregation(x): return min(x)
[docs]def maxabs_aggregation(x): return max(x, key=abs)
[docs]def median_aggregation(x): return median2(x)
[docs]def mean_aggregation(x): return mean(x)
[docs]class InvalidAggregationFunction(TypeError): pass
[docs]def validate_aggregation(function): # TODO: Recognize when need `reduce` if not isinstance(function, (types.BuiltinFunctionType, types.FunctionType, types.LambdaType)): raise InvalidAggregationFunction("A function object is required.") if not (function.__code__.co_argcount >= 1): raise InvalidAggregationFunction("A function taking at least one argument is required")
[docs]class AggregationFunctionSet(object): """Contains aggregation functions and methods to add and retrieve them.""" def __init__(self): self.functions = {} self.add('product', product_aggregation) self.add('sum', sum_aggregation) self.add('max', max_aggregation) self.add('min', min_aggregation) self.add('maxabs', maxabs_aggregation) self.add('median', median_aggregation) self.add('mean', mean_aggregation)
[docs] def add(self, name, function): validate_aggregation(function) self.functions[name] = function
[docs] def get(self, name): f = self.functions.get(name) if f is None: raise InvalidAggregationFunction("No such aggregation function: {0!r}".format(name)) return f
[docs] def __getitem__(self, index): warnings.warn("Use get, not indexing ([{!r}]), for aggregation functions".format(index), DeprecationWarning) return self.get(index)
[docs] def is_valid(self, name): return name in self.functions