AttributeError using metric on differential manifold [closed]

asked 2020-02-12 15:35:10 +0200

A. gravatar image

Hello everyone,

I am getting started with SageMath and try to define a metric on a differential manifold. Despite tutorials, search online and asking questions to colleagues, I cannot understand the following error.

Here is the code, with Kernel SageMath 9.0

FM = Manifold(2,'FM', structure='Riemannian', start_index=1)

K = FM.metric('K')


which generates the following error AttributeError Traceback (most recent call last) <ipython-input-17-f83570b8b1cf> in <module>() 1 K = FM.metric('K') ----> 2 K[Integer(1),Integer(1)]=Integer(1)

/ext/sage/sage-9.0/local/lib/python3.7/site-packages/sage/tensor/modules/ in __setitem__(self, args, value) 1629 else: 1630 basis = self._fmodule._def_basis -> 1631 self.set_comp(basis)[args] = value 1632 1633 def copy_from(self, other): /ext/sage/sage-9.0/local/lib/python3.7/site-packages/sage/manifolds/differentiable/ in set_comp(self, basis) 883 self._is_zero = False # a priori 884 --> 885 if basis._domain == self._domain: 886 # Setting components on the tensor field domain: 887 return FreeModuleTensor.set_comp(self, basis=basis) AttributeError: 'One' object has no attribute '_domain'

It seems that the index type in the metric is wrong. Is that the problem? Have you some ideas to solve the problem?


edit retag flag offensive reopen merge delete

Closed for the following reason duplicate question by eric_g
close date 2020-02-13 10:26:57.646509