def angle_between(self, vec):
"""
Returns the smallest angle between Vector 'vec' and self.
Parameter
=========
vec : Vector
The Vector between which angle is needed.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> A = ReferenceFrame("A")
>>> v1 = A.x
>>> v2 = A.y
>>> v1.angle_between(v2)
pi/2
>>> v3 = A.x + A.y + A.z
>>> v1.angle_between(v3)
acos(sqrt(3)/3)
"""
vec1 = self.normalize()
vec2 = vec.normalize()
angle = acos(vec1.dot(vec2))
return angle
def angle_between(self, vec):
"""
Returns the smallest angle between Vector 'vec' and self.
Parameter
=========
vec : Vector
The Vector between which angle is needed.
Examples
========
>>> from sympy.physics.vector import ReferenceFrame
>>> A = ReferenceFrame("A")
>>> v1 = A.x
>>> v2 = A.y
>>> v1.angle_between(v2)
pi/2
>>> v3 = A.x + A.y + A.z
>>> v1.angle_between(v3)
acos(sqrt(3)/3)
Warnings
========
Python ignores the leading negative sign so that might
give wrong results.
``-A.x.angle_between()`` would be treated as ``-(A.x.angle_between())``,
instead of ``(-A.x).angle_between()``.
"""
vec1 = self.normalize()
vec2 = vec.normalize()
angle = acos(vec1.dot(vec2))
return angle