def load_dist_config(distid):
    """Creates a configuration with differently distributed
    decision values for positives and negatives, which will
    result in differently shaped performance curves.

    distid = 1: high initial precision (near-horizontal ROC curve)
    distid = 2: low initial precision (near-vertical ROC curve)
    distid = 3: standard performance, (circle-segment-like ROC curve)
    """
    if distid == 1:
        dist_config = {'mean_pos': 1.0, 'sigma_pos': 0.3,
                       'mean_neg': 0.0, 'sigma_neg': 1.0}
    elif distid == 2:
        dist_config = {'mean_pos': 2.0, 'sigma_pos': 2.0,
                       'mean_neg': 0.0, 'sigma_neg': 1.0}
    else:
        dist_config = {'mean_pos': 1.0, 'sigma_pos': 1.0,
                       'mean_neg': 0.0, 'sigma_neg': 1.0}
    return dist_config