From 9db46fd444f3a69d806630154b559858479878f7 Mon Sep 17 00:00:00 2001
From: gyu-don <takumi.kt+git@gmail.com>
Date: Fri, 29 Mar 2019 10:12:47 +0900
Subject: [PATCH] Add numpy backend ccx implementation to improve performance

---
 blueqat/backends/numpy_backend.py | 18 ++++++++++++++++++
 blueqat/gate.py                   |  5 +++++
 2 files changed, 23 insertions(+)

diff --git a/blueqat/backends/numpy_backend.py b/blueqat/backends/numpy_backend.py
index 3cb05a8..a650828 100644
--- a/blueqat/backends/numpy_backend.py
+++ b/blueqat/backends/numpy_backend.py
@@ -253,6 +253,24 @@ def gate_s(self, gate, ctx):
             qubits[(i & (1 << target)) != 0] *= 1.j
         return ctx
 
+    def gate_ccz(self, gate, ctx):
+        c1, c2, t = gate.targets
+        qubits = ctx.qubits
+        n_qubits = ctx.n_qubits
+        i = ctx.indices
+        indices = (i & (1 << c1)) != 0
+        indices &= (i & (1 << c2)) != 0
+        indices &= (i & (1 << t)) != 0
+        qubits[indices] *= -1
+        return ctx
+
+    def gate_ccx(self, gate, ctx):
+        c1, c2, t = gate.targets
+        ctx = self.gate_h(HGate(t), ctx)
+        ctx = self.gate_ccz(CCZGate(gate.targets), ctx)
+        ctx = self.gate_h(HGate(t), ctx)
+        return ctx
+
     def gate_u1(self, gate, ctx):
         qubits = ctx.qubits
         n_qubits = ctx.n_qubits
diff --git a/blueqat/gate.py b/blueqat/gate.py
index 0d33b09..8c53870 100644
--- a/blueqat/gate.py
+++ b/blueqat/gate.py
@@ -227,6 +227,11 @@ def fallback(self, n_qubits):
         ]
 
 
+class CCZGate(Gate):
+    """2-Controlled Z gate"""
+    lowername = "ccz"
+
+
 class U1Gate(OneQubitGate):
     """U1 gate"""
     def __init__(self, targets, lambd, **kwargs):