'Set regression weight for each anchor.
Only positive anchors are set to contribute to the regression loss, so this
method returns a weight of 1 for every positive anchor and 0 for every
negative anchor.
Args:
match: a matcher.Match object that provides a matching between anchors
and groundtruth boxes.
Returns:
reg_weights: a float32 tensor with shape [num_anchors] representing
regression weights'

def _create_regression_weights(self, match):

    reg_weights = tf.cast(match.matched_column_indicator(), tf.float32)
    return reg_weights
