Hi James,

It appears you are trying to plot a None object. My guess is that you have defined a function that constructs a system but didn't return the system from that function.

Best, Anton

On Thu, Sep 3, 2015 at 11:51 PM, james edward hernandez kibwiw@yahoo.com.ph wrote:

Hi all.

I tried to use kwant.lattice.honeycomb() instead of the usual kwant.lattice.square() for the QHE.

I tried to enter kwant.plot(sys) to look at the setup, but it returns an error

TypeError: Unrecognized system type.

Also, when I try to calculate the conductance plateaus (as in the example 5 of the paper) the error was this:

AttributeError: 'NoneType' object has no attribute 'lead_interfaces'

What could be the issue regarding these errors?

Attached is the code for the attempt.

Regards James