Certificate in device

[thisac]

Context: The certificate is needed for the TD3 pipeline. It makes sense adding it to the DeviceSpec class (which contains the device specification). This also warrants a name change of the class, calling it Device rather than DeviceSpec(this also makes sense since we've had a tendency to call DeviceSpec objects simply device).

Note: The plan is to later to remove the sf.Device class altogether and only keep the xcc.Device class. Some further changes need to be made for this to work properly, although this would probably be the better solution in the long run, avoiding using multiple abstractions for the same thing.

Description of the Change:

• The DeviceSpec class is renamed Device.
• A certificate can optionally be passed to the Device initialization along with the specification.
• A certificate method is added to the Device class, which returns the certificate attribute.

Benefits:

• The device certificate can be accessed via Device class objects.
• There's less confusion regarding what a device specification is (is it a dictionary or a DeviceSpec object?).

Possible Drawbacks:

• There's now very little difference between sf.Device and xcc.Device.

Related GitHub Issues: None

[codecov[bot]]

Codecov Report

Merging #679 (f60d9a8) into master (529e97e) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #679   +/-   ##
=======================================
  Coverage   98.33%   98.34%           
=======================================
  Files          75       75           
  Lines        9036     9038    +2     
=======================================
+ Hits         8886     8888    +2     
  Misses        150      150           

Impacted Files	Coverage Δ
strawberryfields/program.py	100.00% <ø> (ø)
strawberryfields/tdm/tdmprogram.py	98.29% <ø> (ø)
strawberryfields/__init__.py	95.83% <100.00%> (ø)
strawberryfields/device.py	96.77% <100.00%> (ø)
strawberryfields/engine.py	95.88% <100.00%> (-0.04%)	:arrow_down:

---

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 529e97e...f60d9a8. Read the comment docs.