Source Code for Module geometry.manifolds.translation_algebra

 1  from . import np, MatrixLieAlgebra, contract 
 2  from .. import extract_pieces, combine_pieces 
 3   
 4   
 5 -class tran(MatrixLieAlgebra): 
 6      '''  
 7          lie algebra for translation 
 8      ''' 
 9       
10      @contract(n="1|2|3") 
11 -    def __init__(self, n): 
12          MatrixLieAlgebra.__init__(self, n + 1, dimension=n) 
13           
14 -    def norm(self, X): 
15          W, v, zero, zero = extract_pieces(X) #@UnusedVariable 
16          return np.linalg.norm(v) 
17   
18 -    def project(self, X): 
19          W, v, zero, zero = extract_pieces(X) #@UnusedVariable 
20          return combine_pieces(W * 0, v, v * 0, 0) 
21   
22 -    def __repr__(self): 
23          return 'tr%s' % (self.n - 1) 
24           
25 -    def interesting_points(self): 
26          points = [] 
27          points.append(self.zero()) 
28          return points 
29          
30      @contract(a='belongs') 
31 -    def vector_from_algebra(self, a): 
32          W, v, zero, zero = extract_pieces(a) #@UnusedVariable 
33          if v.shape == (): 
34              v = v.reshape(1) 
35          assert v.size == self.n - 1 
36          return v 
37   
38      @contract(returns='belongs', v='array[K]') 
39 -    def algebra_from_vector(self, v): 
40          assert v.size == self.n - 1 
41          return combine_pieces(np.zeros((self.n - 1, self.n - 1)), v, v * 0, 0) 
42