Ruby » Ruby master

#

# Returns an angle with another vector. Result is within the [0...Math::PI].

# Vector[1,0].angle_with(Vector[0,1])

# # => 1.5707963267948966

#

def angle_with(v)

raise TypeError, "Expected a Vector, got a #{v.class}" unless v.is_a?(Vector)

Vector.Raise ErrDimensionMismatch if size != v.size

raise ZeroVectorError, "Can't get angle of zero vector" if magnitude == 0 || v.magnitude == 0

Math.acos( inner_product(v) / (magnitude * v.magnitude) )

end

def test_angle_with

assert_in_epsilon(Math::PI, Vector[1, 0].angle_with(Vector[-1, 0]))

assert_in_epsilon(Math::PI/2, Vector[1, 0].angle_with(Vector[0, -1]))

assert_in_epsilon(Math::PI/4, Vector[2, 2].angle_with(Vector[0, 1]))

assert_in_delta(0.0, Vector[1, 1].angle_with(Vector[1, 1]), 0.00001)

assert_raise(Vector::ZeroVectorError) { Vector[1, 1].angle_with(Vector[0, 0]) }

assert_raise(Vector::ZeroVectorError) { Vector[0, 0].angle_with(Vector[1, 1]) }

assert_raise(Matrix::ErrDimensionMismatch) { Vector[1, 2, 3].angle_with(Vector[0, 1]) }

end