Quaternion-number-operation-demo.py

# -*- coding: utf-8 -*-


class QuaternionNumber:
    def __init__(self, r, i, j, k):
        self.r = r
        self.i = i
        self.j = j
        self.k = k

    def __add__(self, other):
        a1, b1, c1, d1 = self.r, self.i, self.j, self.k
        a2, b2, c2, d2 = other.r, other.i, other.j, other.k
        return (QuaternionNumber(a1 + a2, b1 + b2, c1 + c2, d1 + d2))

    def __mul__(self, other):
        a1, b1, c1, d1 = self.r, self.i, self.j, self.k
        a2, b2, c2, d2 = other.r, other.i, other.j, other.k
        return (QuaternionNumber(a1 * a2 - b1 * b2 - c1 * c2 - d1 * d2,
                                 a1 * b2 + b1 * a2 + c1 * d2 - d1 * c2,
                                 a1 * c2 - b1 * d2 + c1 * a2 + d1 * b2,
                                 a1 * d2 + b1 * c2 - c1 * b2 + d1 * a2))

    def sign(self, number, suffix):
        signed = str(number) + suffix
        if number == 0:
            return ''
        if number > 0:
            signed = '+' + signed
        return signed

    def show(self):
        r, i, j, k = self.r, self.i, self.j, self.k
        print self.sign(r, '') + self.sign(i, 'i') + self.sign(j, 'j') + self.sign(k, 'k')


if __name__ == "__main__":
    a = QuaternionNumber(2, -1, 1, -1)
    b = QuaternionNumber(0, 1, 1, -1)
    c = QuaternionNumber(1, 1, 2, 2)

    a.show()
    b.show()
    c.show()

    (a + b).show()
    (b * c).show()
    (a * b * c).show()