Stabilizer simulator

referenceqvm/api.py

@@ -1,10 +1,11 @@
 """
 Sets up the appropriate QVM, and interfacing.
 """
-from referenceqvm.gates import gate_matrix
+from referenceqvm.gates import gate_matrix, stabilizer_gate_matrix
 from referenceqvm.qvm_wavefunction import QVM_Wavefunction
 from referenceqvm.qvm_unitary import QVM_Unitary
 from referenceqvm.qvm_density import QVM_Density
+from referenceqvm.qvm_stabilizer import QVM_Stabilizer
 
 
 def QVMConnection(type_trans='wavefunction',
@@ -35,6 +36,8 @@ def QVMConnection(type_trans='wavefunction',
         elif type_trans == 'density':
             qvm = QVM_Density(gate_set=gate_set, noise_model=noise_model)
 
+        elif type_trans == 'stabilizer':
+            qvm = QVM_Stabilizer(gate_set=stabilizer_gate_matrix)
         else:
             raise TypeError("{} is not a valid QVM type.".format(type_trans))
 

referenceqvm/gates.py

@@ -226,6 +226,16 @@ def BARENCO(alpha, phi, theta):
     'CZ': CZ
 }
 
+stabilizer_gate_matrix = {
+    'I': I,
+    'X': X,
+    'Y': Y,
+    'Z': Z,
+    'H': H,
+    'CNOT': CNOT,
+    'S': S,
+    'CZ': CZ
+}
 
 # noisy gates
 def relaxation(p):

referenceqvm/qam.py

@@ -18,6 +18,7 @@
 QAM superclass. Implements state machine model, program loading and processing,
 kernel - leaving details of evolution up to subclasses.
 """
+import sys
 import numpy as np
 
 from referenceqvm.unitary_generator import value_get
@@ -26,7 +27,8 @@
 from pyquil.quilbase import (Gate,
                              Measurement,
                              UnaryClassicalInstruction,
-                             BinaryClassicalInstruction)
+                             BinaryClassicalInstruction,
+                             Label, JumpTarget)
 
 
 class QAM(object):
@@ -91,8 +93,7 @@ def load_program(self, pyquil_program):
 
         # NOTE: all_inst is set by the subclass
         if invalid is True and self.all_inst is False:
-            raise TypeError("In QVM_Unitary, only Gates and DefGates are "
-                            "supported")
+            raise TypeError("Some gates used are not allowed in this QAM")
 
         # set internal program and counter to their appropriate values
         self.program = pyquil_program
@@ -105,6 +106,17 @@ def load_program(self, pyquil_program):
         self.num_qubits = q_max
         self.classical_memory = np.zeros(c_max).astype(bool)
 
+    def memory_reset(self):
+        if self.program is None:
+            raise TypeError("Program must be loaded to call reset")
+
+        # setup quantum and classical memory
+        q_max, c_max = self.identify_bits()
+        if c_max <= 512:  # allocate at least 512 cbits (as floor)
+            c_max = 512
+        self.num_qubits = q_max
+        self.classical_memory = np.zeros(c_max).astype(bool)
+
     def identify_bits(self):
         """
         Iterates through QAM program and finds number of qubits and cbits
@@ -168,6 +180,26 @@ def kernel(self):
             if halted:
                 break
 
+    def find_label(self, label):
+        """
+        Helper function that iterates over the program and looks for a
+        JumpTarget that has a Label matching the input label.
+
+        :param Label label: Label object to search for in program
+
+        :return: program index where Label is found
+        :rtype: int
+        """
+        assert isinstance(label, Label)
+        for index, action in enumerate(self.program):
+            if isinstance(action, JumpTarget):
+                if label == action.label:
+                    return index
+
+        # Label was not found in program.
+        raise RuntimeError("Improper program - Jump Target not found in the "
+                           "input program!")
+
     def transition(self, instruction):
         """
         Abstract class for the transition type