basic_example.json fails during routine verification

[bdg221]

Describe the bug

After reading in basic_example.json, trying to run compile_routine results in the following error:

Traceback (most recent call last):
  File "/Users/xxx/Documents/PsiQuantum/brian/bartiq/src/bartiq/test2.py", line 10, in <module>
    compiled_routine = compile_routine(uncompiled_routine)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/xxx/Documents/PsiQuantum/brian/bartiq/src/bartiq/compilation/_compile.py", line 86, in compile_routine
    return _compile_routine(routine, backend, precompilation_stages, global_functions, functions_map, skip_verification)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/xxx/Documents/PsiQuantum/brian/bartiq/src/bartiq/compilation/_compile.py", line 102, in _compile_routine
    raise BartiqCompilationError(
bartiq.errors.BartiqCompilationError: Found the following issues with the provided routine before the compilation started: ['N is present in linked_params, but not in input_params.\n']

This is the result of changes made in #76 which introduced routine verification.

How to Reproduce

The following code will reproduce the error:

import json
from bartiq import Routine, compile_routine, evaluate
from bartiq.integrations import qref_to_bartiq

with open("docs/data/basic_example.json", "r") as f:
    routine_dict = json.load(f)

uncompiled_routine = qref_to_bartiq(routine_dict)
compiled_routine = compile_routine(uncompiled_routine)

Expected behavior

It is expected that the provided JSON file can be read and used to generated a compiled routine.

Actual behavior

An error is thrown:

bartiq.errors.BartiqCompilationError: Found the following issues with the provided routine before the compilation started: ['N is present in linked_params, but not in input_params.\n']

Environment:**

• OS: OSX,
• Bartiq 0.5.0
• Python 3.11.9

[bdg221]

Adding N in input_params for my_algorithm does correct this error. However, it then results in the following warning:

/Users/xxx/Documents/PsiQuantum/brian/bartiq/src/bartiq/compilation/_compile.py:117: UserWarning: Found the following issues with the provided routine after the compilation has finished: ["Symbol N_b found in subroutine: my_algorithm.b, which is not among top level params: {'N'}."]
  warnings.warn(

This is also seen in the tutorials/01_basic_example (https://psiq.github.io/bartiq/latest/tutorials/01_basic_example/):

This is a bit odd as both the test with the code snippet above, as well as the tutorial, have my_algorithm.a with N_a (or n_a) and there are not warnings for that.

If this should be addressed in a separate issue, please let me know.

[bdg221]

After more research, it appears that the warning is a result of a bug. Before the compilation (after precompile), the resources have the following values:
a -> {'T_gates': <Resource name="T_gates" value="2*N_a">}
b -> {'T_gates': <Resource name="T_gates" value="N_b*ceil(log_2(N_b))">}

After compilation, the resources have the following values:
a -> {'T_gates': <Resource name="T_gates" value="2*N">}
b -> {'T_gates': <Resource name="T_gates" value="N_b*ceiling(log2(N_b))">}

During the compilation N_b is not replaced with N. This explains why the warning is only for N_b.

@mstechly, it looks like you saw a similar warning before and mentioned it in #72 I am happy to continue tracking this down. Do you think I should do that work with #72 or open a new issue?

I will leave this issue for correcting basic_example.json to include input_params.

[mstechly]

Hey @bdg221, thanks a lot for finding this!
Please put it on hold for now, as we're making some refactors which might solve it and I don't want you to waste time on this if that's the case.