Deep copy from Program.compile()
#688
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@@ Coverage Diff @@
## master #688 +/- ##
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Coverage 98.69% 98.69%
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Files 75 75
Lines 9209 9212 +3
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+ Hits 9089 9092 +3
Misses 120 120
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| if name not in ("circuit", "reg_refs", "init_reg_refs"): | ||
| setattr(p, name, copy.deepcopy(val)) |
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Optimally, we should deep-copy the circuit as well, but since the may contain regrefs, this isn't as straight-forward to do. Just making a deepcopy here would cause two errors:
- Due to
MeasuredParameternot supportingdeepcopy(because of the different signature of the__new__()method). A__deepcopy__()method would potentially need to be added. - Any copied (not referenced) regrefs would raise the unnerving
"RegRef state has become inconsistent."issue we had earlier.
We could e.g., override the __deepcopy__ method for the Command class, but that would require it to only deep-copy everything except symbolic parameters. Alternatively, add a copy_everything_except_regref method to Command.
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Because this is a potentially actionable item, perhaps is worth to have it as a (TODO) comment in the code. It might get lost here.
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I've created an issue for this instead (#691). I think it's better to keep track of it there rather than as a TODO which can easily be lost. 🙂
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I've created an issue for this instead (#691). I think it's better to keep track of it there rather than as a TODO which can easily be lost. 🙂
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Great @thisac!
One question only: why programs should share the same references for the registers? Why copy everything else except reg_refs?
Co-authored-by: Sebastián Duque Mesa <[email protected]>
Context:
The compiler create a linked copy of the program by calling
Program._linked_copy(), which retains the same regrefs. Since the copy is shallow, it also keeps the same TDM parameters in a TDM program. These parameters are updated by the compiler and thus changed in both the compiled program and the initial program, while the circuit is only changed in the compiled program.Description of the Change:
Program._linked_copy()is updated to create a deep-copy of all attributes except the ones containing register references, including e.g., the TDM parameters.Benefits:
The compiler actually returns a copy of the program without changing anything in the original program.
Possible Drawbacks:
None
Related GitHub Issues:
None