fix

Author: ciaranra

python/quantum-pecos/src/pecos/qeclib/steane/preps/plus_h_state.py

@@ -89,6 +89,7 @@ def __init__(
                 flag=a[1],
                 out=out[0],
                 out_flag=out[1],
+                with_barriers=True,
             ),
         )
 

python/quantum-pecos/src/pecos/qeclib/steane/steane_class.py

@@ -74,6 +74,8 @@ def __init__(
         self.a = ancillas or QReg(f"{name}_a", 3)
         if flag_qubits is not None:
             self.f = flag_qubits or QReg(f"{name}_f", 3)
+        else:
+            self.f = None
         self.c = CReg(f"{name}_c", 32)
 
         if self.a.size < 3:
@@ -791,7 +793,6 @@ def qec_tel_z(
     def qec_knill(self):
         """prepare a Bell state and then teleport"""
         # TODO: ...
-        ...
         raise NotImplementedError("qec_knill not implemented.")
 
     def syn_bare(self, syn: CReg) -> Block:

python/quantum-pecos/src/pecos/slr/gen_codes/gen_qasm.py

@@ -53,17 +53,21 @@ def enter_block(self, block):
                 self.write(f"// Generated using: PECOS version {__version__}")
             for var in block.vars:
                 var_def = self.process_var_def(var)
-                self.write(var_def)
+                if var_def:
+                    self.write(var_def)
 
             for op in block.ops:
                 op_name = type(op).__name__
                 if op_name == "Vars":
                     for var in op.vars:
                         var_def = self.process_var_def(var)
-                        self.write(var_def)
+                        if var_def:
+                            self.write(var_def)
         return previous_scope
 
     def process_var_def(self, var) -> str:
+        if var is None:
+            return ""
         var_type = type(var).__name__
         return f"{var_type.lower()} {var.sym}[{var.size}];"