# Revision history [back]

### Changing chart multiple times in sagemanifolds

In sagemanifolds, I would like to change from an initial chart to a second and then, from the second to the third. My attempts fail. Is this my fault or a sagemanifolds problem? (Apologies if I already asked this.)

Here is a minimal (not) working example. I run the following file:

theManifold = Manifold(1, 'M', r'\mathcal{M}')
theOpenSet = theManifold.open_subset('U')

theFirstChart.<x> = theOpenSet.chart(r'x')

g = theManifold.riemannian_metric('g')
g[0,0] =  1

show(g.display())

theSecondChart.<y> = theOpenSet.chart(r'y')
ChangeFirst_to_Second = theFirstChart.transition_map(theSecondChart,[x])

show(g.display(theSecondChart.frame()))

theThirdChart.<z> = theOpenSet.chart(r'z')
ChangeSecond_to_Third = theSecondChart.transition_map(theThirdChart,[y])

show(g.display(theThirdChart.frame()))


The output is

g=dx⊗dx
g=dy⊗dy


and then a few screens of error messages, of which the most clear is "no common chart for the multiplication".