carry lookahead adder

mathematics/draper0406142/carry_looahead_adder.py

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+import cirq
+import numpy as np
+
+class CarryLookaheadAdder:
+    def __init__(self, A, B):
+        self.A, self.B = A, B
+        self.circuit = self.construct_circuit()
+
+    def construct_moments(self):
+        n = len(self.A)
+        p = {}
+        g = {}
+        g[(0,1)] = cirq.NamedQubit("g"+str((0, 1)))
+
+        for i in range(1,n):
+            p[(i, i+1)]=B[i]
+            g[(i,i+1)] = cirq.NamedQubit("g"+str((i, i+1)))
+
+        init = [cirq.TOFFOLI(A[i], B[i], g[(i, i+1)]) for i in range(n)]
+        init += [cirq.CNOT(A[i], B[i]) for i in range(n)]
+
+        # P-ROUND
+        p_moments = []
+        st = int(np.log2(n))
+        for t in range(1, st):
+            st1 = int(n/(2**t))
+            for m in range(1, st1):
+                i = 2**(t-1)*2*m
+                j = 2**(t-1)*(2*m+1)
+                k = 2**t*m
+                p[(k, k+2**t)]=cirq.NamedQubit("p"+str((k, k+2**t)))
+                p_moments += [cirq.TOFFOLI(p[(i, i+2**(t-1))], p[(j, j+2**(t-1))], p[(k, k+2**t)])]
+
+        # G-ROUND
+        g_moments = []
+        g_moments_inv = []
+        for t in range(1, st+1):
+            st1 = int(n/(2**t))
+            for m in range(st1):
+                i = 2**t*m
+                j = i+2**t
+                k = 2**t*m+2**(t-1)
+                g[(i,j)] = g[(j-1,j)]
+                g_moments += [cirq.TOFFOLI(g[(i,k)], p[k, j], g[i,j])]
+                if j!=n:
+                    g_moments_inv += [cirq.TOFFOLI(g[(i,k)], p[k, j], g[i,j])]
+
+        # C-ROUND
+        c_moments = []
+        c_moments_inv = []
+        st2 = int(np.log2(2*n/3))
+        for t in range(st2,0,-1):
+            st1 =  int((n-2**(t-1))/(2**t))
+            for m in range(1,st1+1):
+                j = 2**t*m+2**(t-1)
+                k = 2**t*m
+                c_moments += [cirq.TOFFOLI(g[(k-1,k)], p[(k,j)], g[(j-1,j)])]
+                if j!=n:
+                    c_moments_inv += [cirq.TOFFOLI(g[(k-1,k)], p[(k,j)], g[(j-1,j)])]
+
+        last_round = [cirq.CNOT(g[(i,i+1)], B[i+1]) for i in range(n-1)]
+        last_round += [cirq.X(B[i]) for i in range(n-1)]
+        last_round += [cirq.CNOT(A[i], B[i]) for i in range(1,n-1)]
+
+        p_moments_inv = p_moments[:int(n/2)-2]+p_moments[int(n/2)-1:]
+
+        init_inv = init[::-1][1:n]+init[::-1][n+1:]
+
+        return init, p_moments, g_moments, c_moments, last_round, p_moments_inv, c_moments_inv[::-1], g_moments_inv[::-1], init_inv
+
+    def construct_circuit(self):
+
+        init, p_round, g_round, c_round, last_round, p_round_inv, c_round_inv, g_round_inv, init_inv = self.construct_moments()
+
+        circuit = cirq.Circuit(init)
+
+        circuit.append(p_round)
+
+        circuit.append(g_round)
+
+        circuit.append(c_round)
+
+        circuit.append(p_round[::-1])
+
+        circuit.append(last_round)
+
+        circuit.append(p_round_inv)
+
+        circuit.append(c_round_inv)
+
+        circuit.append(g_round_inv)
+
+        circuit.append(p_round_inv[::-1])
+
+        circuit.append(init_inv)
+
+        for i in range(len(self.A)-1):
+            circuit.append(cirq.X(self.B[i]))
+
+        return circuit
+