Added code for running QLBM on IonQ backend and flag qubit mitigation without midcircuit measurements

qlbm/qlbm_sample_app.py

@@ -251,7 +251,7 @@ def stream(qc,pos_qr,dir_qr,n):
       qc.cp( np.pi / (2 ** m), forw_ctrl,  pos_qr[i][m])
       qc.cp(-np.pi / (2 ** m), backw_ctrl, pos_qr[i][m])
 
-def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure=True,flag_qubits=False):
+def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure=True,flag_qubits=False,midcircuit_meas=True):
 
   ux_str,uy_str,uz_str=None,None,None
   if type(ux)==str:
@@ -277,14 +277,23 @@ def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure
   for T_total in T_list:
     pos_qr=[QuantumRegister(n) for _ in range(dim)]
     pos_cr=[ClassicalRegister(n) for _ in range(dim)]
-    dir_qr=QuantumRegister(2*dim)
+    if midcircuit_meas:
+      dir_qr=QuantumRegister(2*dim)
+    else:
+      dir_qr_list=[QuantumRegister(2*dim) for _ in range(T_total)]
     dir_qr_flag=QuantumRegister(2*dim)
-    dir_cr=[ClassicalRegister((4 if flag_qubits else 2)*dim) for _ in range(T_total)]
+    dir_cr=[ClassicalRegister((4 if flag_qubits and midcircuit_meas else 2)*dim) for _ in range(T_total+int(flag_qubits and not midcircuit_meas))]
 
     if flag_qubits:
-      qc=QuantumCircuit(*pos_qr,dir_qr,dir_qr_flag,*pos_cr,*dir_cr)
+      if midcircuit_meas:
+        qc=QuantumCircuit(*pos_qr,dir_qr,dir_qr_flag,*pos_cr,*dir_cr)
+      else:
+        qc=QuantumCircuit(*pos_qr,*dir_qr_list,dir_qr_flag,*pos_cr,*dir_cr)
     else:
-      qc=QuantumCircuit(*pos_qr,dir_qr,*pos_cr,*dir_cr)
+      if midcircuit_meas:
+        qc=QuantumCircuit(*pos_qr,dir_qr,*pos_cr,*dir_cr)
+      else:
+        qc=QuantumCircuit(*pos_qr,*dir_qr_list,*pos_cr,*dir_cr)
 
     qc.compose(init_state_prep_circ,[qubit for qr in pos_qr for qubit in list(qr)], inplace=True)
 
@@ -300,7 +309,11 @@ def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure
 
     for T in list(range(T_total))[::-1]:
 
+      if not midcircuit_meas:
+        dir_qr=dir_qr_list[T]
+
       prep(qc,pos_qr,dir_qr)
+
       if flag_qubits:
         for q1,q2 in zip(dir_qr,dir_qr_flag):
           qc.cx(q1,q2)
@@ -316,11 +329,14 @@ def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure
           qc.cx(q1,q2)
       unprep(qc,pos_qr,dir_qr)
 
-      if flag_qubits:
+      if flag_qubits and midcircuit_meas:
         qc.measure(list(dir_qr)+list(dir_qr_flag),dir_cr[T])
       else:
         qc.measure(dir_qr,dir_cr[T])
 
+    if not midcircuit_meas and flag_qubits:
+      qc.measure(dir_qr_flag,dir_cr[T_total])
+
     if uniform_bool:
       for i in range(dim):
         qc.compose(QFT(n, inverse=True, do_swaps=False), pos_qr[i], inplace=True)
@@ -328,7 +344,7 @@ def get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution=32,measure
     if measure:
       for i in range(dim):
         qc.measure(pos_qr[i],pos_cr[i])
-    
+
     qc_list+=[qc]
 
   return qc_list
@@ -590,6 +606,101 @@ def run_sampling_hw_ibm(
   
   return job,get_job_result
 
+from qiskit_ionq import IonQProvider
+
+provider = IonQProvider("qDwgg6JWfESewd6hbrxLL7e6H8OU0yop")
+
+def run_sampling_hw_ionq(
+    n,
+    ux,
+    uy,
+    uz,
+    init_state_prep_circ,
+    T_list,
+    shots=2**19,
+    vel_resolution=32,
+    output_resolution=40,
+    logger=None,
+    flag_qubits=True
+):
+  """
+  Run QLBM simulation on IBM quantum hardware.
+  
+  Parameters
+  ----------
+  n : int
+      Number of qubits per spatial dimension
+  ux, uy, uz : callable or str
+      Velocity field components
+  init_state_prep_circ : QuantumCircuit
+      Pre-built initial state preparation circuit from get_named_init_state_circuit()
+  T_list : list[int]
+      List of timesteps to simulate
+  shots : int
+      Number of measurement shots (default: 2^19)
+  vel_resolution : int
+      Resolution for velocity field discretization
+  output_resolution : int
+      Grid resolution for density estimation output
+  logger : callable, optional
+      Function to log messages (e.g. print to console)
+  
+  Returns
+  -------
+  job : IonQ Job
+      The submitted job object
+  get_job_result : callable
+      Callback function to retrieve and process results. Returns (output, fig).
+  """
+
+  def log(msg):
+      if logger:
+          logger(str(msg))
+      else:
+          print(msg)
+
+  # if type(ux)==str:
+  #   ux,uy,uz=str_to_lambda(ux,uy,uz)
+
+  # # Convert string init_state_prep_circ to circuit if needed (matches original logic)
+  # if type(init_state_prep_circ)==str:
+  #   init_state_prep_circ=get_named_init_state_circuit(n,init_state_prep_circ)
+
+  qc_list=get_circuit(n,ux,uy,uz,init_state_prep_circ,T_list,vel_resolution,flag_qubits=flag_qubits,midcircuit_meas=False)
+
+  backend = provider.get_backend("qpu.forte-enterprise-1")
+
+  # Create Sampler primitive bound to the backend
+
+  job = backend.run(qc_list, shots=shots)
+
+  # sampler = Sampler(mode=backend)
+
+  # # Submit job: pass a list of PUBs (we send one PUB [qc_compiled])
+  # job = sampler.run(qc_compiled_list, shots=shots)
+  log("Job submitted; waiting for result...")
+
+  def get_job_result(j):
+    
+    log("Waiting for job results (this may take time)...")
+
+    output=[]
+
+    for i,T_total in enumerate(T_list):
+
+      counts = j.get_counts(i)
+
+      # Suppress verbose logging by passing None as logger
+      pts, counts = load_samples(counts, T_total, logger=None, flag_qubits=flag_qubits, midcircuit_meas=False)
+      output+=[estimate_density(pts, counts, bandwidth=0.05, grid_size=output_resolution)]
+
+    log(f"Processing complete: {len(output)} timestep(s)")
+    fig = plot_density_isosurface_slider(output, T_list)
+    return output, fig
+  
+  return job,get_job_result
+
+
 
 from qiskit_aer import AerSimulator
 
@@ -983,7 +1094,7 @@ if __name__=="__main__":
   # show_initial_distribution(n=n, init_state_name="sin", sine_k_x=1, sine_k_y=1, sine_k_z=1)
 
   # Step 3: Run simulation - pass the pre-built circuit
-  job, get_job_result = run_sampling_hw_ibm(
+  job, get_job_result = run_sampling_hw_ionq(
       n=n,
       ux="1",
       uy="1",
@@ -992,7 +1103,7 @@ if __name__=="__main__":
       T_list=[1,2],
       shots=2**19,
       vel_resolution=2,
-      output_resolution=8,
+      output_resolution=16,
       flag_qubits=True
   )
 

qlbm/visualize_counts.py

@@ -22,7 +22,7 @@ def bitstring_to_xyz(bs):
     maxv = (1 << t)
     return ix / maxv, iy / maxv, iz / maxv
 
-def load_samples(d, T_total, logger=None, flag_qubits=False):
+def load_samples(d, T_total, logger=None, flag_qubits=False, midcircuit_meas=True):
   """
   Load samples from measurement counts dictionary.
   
@@ -51,23 +51,29 @@ def load_samples(d, T_total, logger=None, flag_qubits=False):
   pts = []
   counts = []
 
-  pref_length=6*T_total
   if flag_qubits:
+    if midcircuit_meas:
       pref_length=12*T_total
+    else:
+      pref_length=6*(T_total+1)
+  else:
+    pref_length=6*T_total
+      
   
   if d is None or len(d) == 0:
-      log("Warning: Empty counts dictionary")
-      return np.array(pts), np.array(counts)
+    log("Warning: Empty counts dictionary")
+    return np.array(pts), np.array(counts)
   
   # Debug: show sample bitstrings
   sample_keys = list(d.keys())[:3]
   log(f"Sample bitstrings (first 3): {sample_keys}")
   if sample_keys:
-      log(f"Bitstring length: {len(sample_keys[0])}")
-      log(f"Expected prefix length: {pref_length}")
+    log(f"Bitstring length: {len(sample_keys[0])}")
+    log(f"Expected prefix length: {pref_length}")
   
   for bs, cnt in d.items():
     # Check if the direction qubits (first 6*T_total bits) are all zeros
+    bs=bs.replace(" ","")
     prefix = bs[:pref_length]
     expected_prefix = "0" * pref_length