linear algebra

vector.py

class Vector(object):

    def __init__(self, coords):
        self.coordinates = coords
        self.dimensions = len(coords)

    def __str__(self):
        return "Vector: {}".format(self.coordinates)

    def __eq__(self, v):
        return self.coordinates == v.coordinates


def add_vectors(*vecs):  # of variable length :)
    largest = max([v.dimensions for v in vecs])

    result = [0] * largest
    for v in vecs:
        for idx, p in enumerate(v.coordinates):
            result[idx] += p

    return Vector(result)


def sub_vectors(*vecs):
    largest = max([v.dimensions for v in vecs])
    result = [0] * largest
    for idx, p in enumerate(vecs[0].coordinates):
        result[idx] = p

    vecs = vecs[1:]
    for v in vecs:
        for idx, p in enumerate(v.coordinates):
            result[idx] -= p

    return Vector(result)


def scale_vector(scalar, vec):
    result = [0] * vec.dimensions
    for idx, p in enumerate(vec.coordinates):
        result[idx] = p * scalar

    return Vector(result)


if __name__ == "__main__":
    y = Vector([-11, 3, 4])
    x = Vector([-1, 2, 6, 0])
    w = Vector([1, 5, 2, 19])
    print(add_vectors(x, y, w))
    w = Vector([1, 5, 2, 19])
    x = Vector([1, 2, 6, 0])
    y = Vector([1, 3, 4])
    print(sub_vectors(w, x, y))
    y = Vector([1, 3, 4])
    s = .5
    print(scale_vector(s, y))

    print("QUESTION 1")
    print(add_vectors(Vector([8.218, -9.341]), Vector([-1.129, 2.111])))
    print(sub_vectors(Vector([7.119, 8.215]), Vector([-8.223, 0.878])))
    print(scale_vector(7.41, Vector([1.671, -1.012, -0.318])))