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|
| | class ThresholdOperation(): |
| | """Represents the threshold operations that are used in postprocessing approaches. |
| | |
| | Threshold operations simply indicate a threshold and an operator, thereby defining a function. |
| | The function can be evaluated at arbitrary points (usually the scores returned from |
| | unconstrained predictors) to return a bool value. |
| | |
| | :param operator: the threshold operator, can be either '>' or '<' |
| | :type operator: str |
| | :param threshold: the threshold, can be numpy.inf or -numpy.inf |
| | :type threshold: float |
| | """ |
| |
|
| | def __init__(self, operator, threshold): |
| | if operator not in ['>', '<']: |
| | raise ValueError("Unrecognized operator: " + operator) |
| | self._operator = operator |
| | self._threshold = threshold |
| |
|
| | @property |
| | def threshold(self): |
| | """Return the stored threshold.""" |
| | return self._threshold |
| |
|
| | @property |
| | def operator(self): |
| | """Return the stored threshold operator.""" |
| | return self._operator |
| |
|
| | def get_predictor_from_operation(self): |
| | """Encode the threshold rule `Y_hat > t` or `Y_hat < t`. |
| | |
| | :return: a function that takes a single argument to evaluate it against the threshold rule |
| | :rtype: lambda |
| | """ |
| | if self._operator == '>': |
| | return lambda x: x > self._threshold |
| | elif self._operator == '<': |
| | return lambda x: x < self._threshold |
| | else: |
| | raise ValueError("Unrecognized operator: " + self._operator) |
| |
|
| | def __repr__(self): |
| | return "[{}{}]".format(self._operator, self._threshold) |
| |
|
