average_precision_calculator.py 文件源码

def __init__(self, top_n=None):
    """Construct an AveragePrecisionCalculator to calculate average precision.

    This class is used to calculate the average precision for a single label.

    Args:
      top_n: A positive Integer specifying the average precision at n, or
        None to use all provided data points.

    Raises:
      ValueError: An error occurred when the top_n is not a positive integer.
    """
    if not ((isinstance(top_n, int) and top_n >= 0) or top_n is None):
      raise ValueError("top_n must be a positive integer or None.")

    self._top_n = top_n  # average precision at n
    self._total_positives = 0  # total number of positives have seen
    self._heap = []  # max heap of (prediction, actual)