New string

qiskit_device_benchmarking/bench_code/mrb/mirror_qa.py

@@ -12,13 +12,13 @@
 """
 Mirror QA Experiment class.
 """
 from typing import Union, Iterable, Optional, List, Sequence
 import numpy as np
 from numpy import pi
 from numpy.random import Generator, BitGenerator, SeedSequence
 from scipy.stats import entropy
 from uncertainties import unumpy as unp
 from scipy.spatial.distance import hamming
 
 from qiskit.circuit import Instruction
 from qiskit.providers.backend import Backend
@@ -221,6 +221,19 @@
         )
         self._coupling_map = coupling_map
         self._pairs = pairs
+        self._singles = singles
+
+    def _rewrite_string(self, string, index):
+        '''
+        Returns a string of equal length, pairs have parity on the lowest numbered qubit
+        and 0 on the highest.
+        '''
+        pair_string = ["0"]*len(string)
+        for q in self._singles[index]:
+            pair_string[-1-q] = string[-1-q]
+        for q0, q1 in self._pairs[index]:
+            pair_string[-1-min(q0,q1)] = str(int(string[-1-q0]!=string[-1-q1]))
+        return ''.join(pair_string)
 
     def _process(self, data: np.ndarray):
         if self._analyzed_quantity == "Mutual Information":

qiskit_device_benchmarking/bench_code/mrb/mirror_rb_analysis.py

@@ -262,19 +262,24 @@ def __init__(
         self._analyzed_quantity = analyzed_quantity
         self._target_bs = target_bs
 
+    def _rewrite_string(string, index):
+        '''Returns string unchanged. Will be overwritten for Mirror QA'''
+        return string
+
     def _process(self, data: np.ndarray):
         # Arrays to store the y-axis data and uncertainties
         y_data = []
         y_data_unc = []
 
         for i, circ_result in enumerate(data):
-            target_bs = self._target_bs[i]
+            target_bs = self._rewrite_string(self._target_bs[i], i)
 
             # h[k] = proportion of shots that are Hamming distance k away from target bitstring
             hamming_dists = np.zeros(self._num_qubits + 1)
             success_prob = 0.0
             success_prob_unc = 0.0
             for bitstring, count in circ_result.items():
+                bitstring = self._rewrite_string(bitstring, i)
                 # Compute success probability
                 if self._analyzed_quantity == "Success Probability":
                     if bitstring == target_bs: