Offset support in Wigner and other visualizations

[Krastanov]

Is your feature request related to a problem? Please describe.
For coherent states of large average photon number it is convenient to use the offset parameter as in http://qutip.org/docs/latest/apidoc/functions.html?highlight=wigner#qutip.states.coherent

However, wigner and others do not support that parameter and would just give wrong results.

Describe the solution you'd like
Functions like http://qutip.org/docs/latest/apidoc/functions.html?highlight=wigner#qutip.wigner.wigner , http://qutip.org/docs/latest/apidoc/functions.html?highlight=wigner#qutip.visualization.plot_wigner_fock_distribution , and others could support an offset parameter or the offset parameter can be stored in the qobject.

Describe alternatives you've considered
Calculating these functions manually. It works but it is pretty annoying.

[lambaaryan011]

Hi @Krastanov still this issue in the working period ?

[Ericgig]

This issue still hasn't been fixed.
We are open for contribution.

[lambaaryan011]

Hey @Ericgig could you please assign this issue to me? I'd love to take it on!

[Ericgig]

We don't really assign issue, just make a PR.
It's been open for a few years, there should not have much conflict.

[lambaaryan011]

Hey @Ericgig, I’m having trouble locating these two functions: qutip.wigner.wigner and qutip.visualization.plot_wigner_fock_distribution. Could you point me to the right folder? I know how to solve this once I find them.

[Ericgig]

plot_wigner_fock_distribution does not exist anymore, it was replaced with plot_wigner and plot_fock_distribution.
wigner is still as is,.
They are in the "qutip" folder... just search for them in your editor.