Add warning if digital carrier exceeds Nyquist frequency in pulse -> signal conversion #242
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Thanks @DanPuzzuoli this is really helpful improvement. I was thinking shift and set frequency were directly applied to the analog carrier, and had trouble with interpretation of weird simulation results. I think I am not only person suffering this problem :)
The warning is suppressed if the conversion is called within JAX tracing, as in this case the boolean function np.abs(frequency_shift) > 0.5 / dt cannot be evaluated.
This means the warning is also raised at run time even with the JAX backend? Then this PR looks good to me.
| @@ -188,14 +198,15 @@ def get_signals(self, schedule: Schedule) -> List[DiscreteSignal]: | |||
| if isinstance(inst, ShiftPhase): | |||
| phases[chan] += inst.phase | |||
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| if isinstance(inst, SetPhase): | |||
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Is this related to the warning?
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This is not related to the warning: I saw that the SetPhase and ShiftPhase handling were not grouped together, so I moved this block up.
The error will not be raised ever if the converter is called within a traced function. For now this probably won't impact any users; it will still be raised when using the As an aside: This is an unfortunate element of the way JAX works - you can't have warnings/errors that depend on the value of variables that are being traced. Branching logic that depends on the value of a variable will cause an error during tracing, and once compiled, the original code is no longer executed anyway, so no warnings can be raised there. |
* adding sympy as an explicit requirement (#233) * Add warning for JAX versions on import of Dynamics (#232) * Add probability normalization to DynamicsBackend sampling routine (#239) * Add warning if digital carrier exceeds Nyquist frequency in pulse -> signal conversion (#242) * Fix bug with carrier_freq being a JAX tracer if envelope is constant in Signal (#247) * Remove subsystem_labels option from DynamicsBackend (#248) * Rename subsystem_dims Dict to subsystem_dims_dict (#250) * Fix ClassicalRegister counting in DynamicsBackend (#252) * temporary fix for docs (#253) * Drop support for backendV2 in from_backend (#249) * incrementing version number * cleaning up reno files --------- Co-authored-by: Kento Ueda <38037695+to24toro@users.noreply.github.com>
Summary
Closes #241
A warning is added to the pulse -> signal converter if the digital carrier frequency (resulting from
SetFrequencyandShiftFrequencyinstructions) exceeds the Nyquist frequency set by the sample sizedt.Details and comments
The warning is suppressed if the conversion is called within JAX tracing, as in this case the boolean function
np.abs(frequency_shift) > 0.5 / dtcannot be evaluated.A test has been added, and @nkanazawa1989 I've verified that the warning is raised in your example that motivated this PR.