author Dmitriy Morozov <>
Sun, 24 Nov 2019 13:35:45 -0800
changeset 298 02e680f6d987
parent 145 ee096f207dfb
permissions -rw-r--r--
Add .build.yml

from    math        import sqrt

def l2(p):
    return sqrt(sum((x**2 for x in p)))

# Pairwise distances between the elements of `points` with respect to some `norm`
class PairwiseDistances:
    def __init__(self, points, norm = l2):
        self.points = points
        self.norm = norm

    def __len__(self):
        return len(self.points)

    def __call__(self, p1, p2):
        return self.norm((x - y for (x,y) in zip(self.points[p1], self.points[p2])))

# Caches all distances specified by `distances`
class ExplicitDistances:
    def __init__(self, distances):
        self.len = len(distances)
        self.distances = []
        for i in xrange(self.len): 
            for j in xrange(self.len):

    def __len__(self):
        return self.len

    def __call__(self, p1, p2):
        return self.distances[p1][p2]

# Generator of all points in a file `filename` with one point per line
def points_file(filename):
    fd = open(filename)
    for line in fd.xreadlines():
        if line.startswith('#'): continue
        yield map(float, line.strip().split())