feat: option to run on logarithmic scale depths

src/qibocal/protocols/qua/rb_ondevice.py

@@ -29,8 +29,14 @@ class RbOnDeviceParameters(Parameters):
  num_of_sequences: int
  max_circuit_depth: int
  "Maximum circuit depth"
- delta_clifford: int
+ delta_clifford: int = 1
  "Play each sequence with a depth step equals to delta_clifford"
+ logarithmic: bool = False
+ """Use logarithmically scaled depths.
+
+ The depths used in this case are 1, 2^delta_clifford, 2^(2*delta_clifford), ...
+ up to the specified ``max_circuit_depth``.
+ """
  seed: Optional[int] = None
  "Pseudo-random number generator seed"
  n_avg: int = 1
@@ -303,15 +309,21 @@ def _acquisition(
  save(I, I_st)
  save(Q, Q_st)
  # Go to the next depth
- assign(depth_target, depth_target + delta_clifford)
+ if params.logarithmic:
+ nmul = declare(int)
+ with for_(nmul, 0, nmul < delta_clifford, nmul + 1):
+ assign(depth_target, 2 * depth_target)
+ else:
+ assign(depth_target, depth_target + delta_clifford)
  # Reset the last gate of the sequence back to the original Clifford gate
  # (that was replaced by the recovery gate at the beginning)
  assign(sequence_list[depth], saved_gate)
  # Save the counter for the progress bar
  save(m, m_st)
 
+ depths = generate_depths(max_circuit_depth, delta_clifford, params.logarithmic)
  with stream_processing():
- ndepth = max_circuit_depth / delta_clifford + int(delta_clifford > 1)
+ ndepth = len(depths)
  m_st.save("iteration")
  if save_sequences:
  sequence_st.buffer(max_circuit_depth + 1).buffer(num_of_sequences).save(
@@ -350,13 +362,7 @@ def _acquisition(
  ).average().save("Q_avg")
 
  # Print total relaxation time (estimate of execution time)
- total_relaxation = (
- relaxation_time
- * num_of_sequences
- * n_avg
- * (max_circuit_depth // delta_clifford)
- * 1e-9
- )
+ total_relaxation = relaxation_time * num_of_sequences * n_avg * ndepth * 1e-9
  print("\nTotal relaxation time: %.2f sec\n" % total_relaxation)
 
  #####################################
@@ -424,7 +430,7 @@ def _acquisition(
  return RbOnDeviceData(
  rb_type=rb_type,
  relaxation_time=relaxation_time,
- depths=[int(x) for x in generate_depths(max_circuit_depth, delta_clifford)],
+ depths=[int(x) for x in depths],
  data=data,
  )
 

src/qibocal/protocols/qua/utils.py

@@ -48,8 +48,12 @@ def clifford_mul(sequences, interleave=None):
  return result
 
 
-def generate_depths(max_circuit_depth, delta_clifford):
+def generate_depths(max_circuit_depth, delta_clifford, logarithmic=False):
  """Generate vector of depths compatible with the QUA acquisition script."""
+ if logarithmic:
+ return 2 ** np.arange(
+ 0, int(np.log2(max_circuit_depth)) + 0.1, delta_clifford
+ ).astype(int)
  if delta_clifford == 1:
  return np.arange(1, max_circuit_depth + 0.1, delta_clifford).astype(int)
  depths = np.arange(0, max_circuit_depth + 0.1, delta_clifford).astype(int)