No backprop devices

[antalszava]

Context

As lighting.qubit inherits from default.qubit, it also inherits the passthru_devices entry of the device.capabilities dictionary.

This, however, may lead to unexpected behaviour, as the QNode in PennyLane attempts to get a device with the best differentiation method available. Therefore, even without specifying a differentiation method, we may get a default.qubit.autograd device.

Changes

Removes the passthru_devices entry of device.capabilities.

[codecov]

Codecov Report

Merging #61 (bffde19) into master (451f2df) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master       #61   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines           54        54           
=========================================
  Hits            54        54           

Impacted Files	Coverage Δ
pennylane_lightning/lightning_qubit.py	100.00% <ø> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 451f2df...99f073a. Read the comment docs.

[josh146]

Didn't seem to fix the windows wheel :(

[josh146]

Thanks for getting onto this so quickly @antalszava! Before merging, don't forget to update the changelog.