Source Code for Module geometry.manifolds.product_manifold

 1  from . import DifferentiableManifold, contract, np 
 2   
 3   
 4 -class ProductManifold(DifferentiableManifold): 
 5      @contract(components='seq[>=2,N](DifferentiableManifold)', 
 6                weights='None|array[N](>0)') 
 7 -    def __init__(self, components, weights=None): 
 8          dim = sum([m.dimension for m in components]) 
 9          DifferentiableManifold.__init__(self, dimension=dim) 
10          self.components = components 
11          if weights is None: 
12              weights = np.ones(len(components)) 
13          self.weights = weights 
14   
15      @contract(a='seq') 
16 -    def belongs(self, a): 
17          if not len(a) == len(self.components): # XXX: what should I throw? 
18              raise ValueError('I expect a sequence of length %d, not %d.' %  
19                               (len(a), len(self.components))) 
20          for x, m in zip(a, self.components): 
21              m.belongs(x) 
22       
23 -    def distance(self, a, b):  
24          ''' Computes the geodesic distance between two points. ''' 
25          distances = [m.distance_(x) for x, m in zip(a, self.components)] 
26          distances = np.array(distances) 
27          return (distances * self.weights).sum() 
28           
29 -    def logmap(self, a, b):  
30          ''' Computes the logarithmic map from base point *a* to target *b*. ''' 
31          raise ValueError('Not implemented') # FIXME: finish this 
32       
33 -    def expmap(self, a, v): 
34          raise ValueError('Not implemented') # FIXME: finish this 
35           
36 -    def project_ts(self, base, v_ambient): 
37          raise ValueError('Not implemented') # FIXME: finish this 
38       
39 -    def __repr__(self): 
40          return 'P(%s)' % "x".join([str(x) for x in self.components]) 
41