bin.py 文件源码

def bin_dice(predictions: tf.Tensor, labels: tf.Tensor) -> tf.Tensor:
    """
    Calculate Sorensen–Dice coefficient from the given binary classification expected and predicted values.

    The coefficient is defined as :math:`2*|X \cup Y| / (|X| + |Y|)`.

    :param predictions: 2-d tensor (batch, predictions) of predicted 0/1 classes
    :param labels: 2-d tensor (batch, labels) of expected 0/1 classes
    :return: batched Sørensen–Dice coefficients
    """
    predictions = tf.cast(predictions, tf.int32)
    labels = tf.cast(labels, tf.int32)

    true_positives = tf.reduce_sum((predictions * labels), axis=1)
    pred_positives = tf.reduce_sum(predictions, axis=1)
    label_positives = tf.reduce_sum(labels, axis=1)

    return 2 * true_positives / (pred_positives + label_positives)