#!/usr/bin/env python
# -*- coding: UTF-8 -*-
#Copyright (c) 2012-2015 Christian Schwarz
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from pycast.errors import MeanAbsolutePercentageError
[docs]class MedianAbsolutePercentageError(MeanAbsolutePercentageError):
"""Represents the median absolute percentage error."""
[docs] def _calculate(self, startingPercentage, endPercentage, startDate, endDate):
"""This is the error calculation function that gets called by :py:meth:`BaseErrorMeasure.get_error`.
Both parameters will be correct at this time.
:param float startingPercentage: Defines the start of the interval. This has to be a value in [0.0, 100.0].
It represents the value, where the error calculation should be started.
25.0 for example means that the first 25% of all calculated errors will be ignored.
:param float endPercentage: Defines the end of the interval. This has to be a value in [0.0, 100.0].
It represents the value, after which all error values will be ignored. 90.0 for example means that
the last 10% of all local errors will be ignored.
:param float startDate: Epoch representing the start date used for error calculation.
:param float endDate: Epoch representing the end date used in the error calculation.
:return: Returns a float representing the error.
:rtype: float
"""
## get the defined subset of error values
errorValues = self._get_error_values(startingPercentage, endPercentage, startDate, endDate)
errorValues = filter(lambda item: item != None, errorValues)
return sorted(errorValues)[len(errorValues)//2]
MdAPE = MedianAbsolutePercentageError