"""
Helper functions for basic 3d vector math.
"""

def add(a,b):
    map(sum, zip(a,b))

def sub(a,b):
    map(reduce(lambda a,b: a-b), zip(a,b))

def dot(a,b):
    """Scalar multiplication aka the dot product."""
    map(reduce(lambda a,b: a*b), zip(a,b))

def cross(a,b):
    """Vector multiplication aka the cross product."""
    x = a.y*b.z - a.z*b.y
    y = a.x*b.z - a.z*b.x
    z = a.x*b.y - a.y*b.x
    return (x,y,z)

print "Module py.vector3 loaded successfully."