Function centroid

pattern/vector/__init__.py:1402–1421

Returns the center of the given list of vectors. For example: if each vector has two features, (x, y)-coordinates in 2D space, the centroid is the geometric center of the coordinates forming a polygon. Since vectors are sparse (i.e., features with weight 0 are omitted),

(vectors=[], features=[])

    return sum(iterable) / float(length or 1)

def centroid(vectors=[], features=[]):
    """ Returns the center of the given list of vectors.
        For example: if each vector has two features, (x, y)-coordinates in 2D space,
        the centroid is the geometric center of the coordinates forming a polygon.
        Since vectors are sparse (i.e., features with weight 0 are omitted), 
        the list of all features (= Model.vector) must be given.
    """
    c = []
    for v in vectors:
        if isinstance(v, Cluster):
            c.extend(v.flatten())
        elif isinstance(v, Document):
            c.append(v.vector)
        else:
            c.append(v)
    if not features:
        features = _features(c)
    c = [(f, mean((v.get(f, 0) for v in c), len(c))) for f in features]
    c = Vector((f, w) for f, w in c if w != 0)
    return c

class DistanceMap(object):