From 79593ad019bd0c282cb18dea036bcb45946e44a3 Mon Sep 17 00:00:00 2001
From: Jonathan Daniel <jonathand655@gmail.com>
Date: Sun, 5 Jun 2022 11:20:54 +0300
Subject: [PATCH] Add a trace simulator in C# for custom resources estimation

Count every operation and not just T in the depth
---
 mcx/qsharp/MultiControlX.qs      | 13 ++++++-
 mcx/qsharp/ResourcesEstimator.cs | 64 ++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 mcx/qsharp/ResourcesEstimator.cs

diff --git a/mcx/qsharp/MultiControlX.qs b/mcx/qsharp/MultiControlX.qs
index 7e6ea35..99dc1b1 100644
--- a/mcx/qsharp/MultiControlX.qs
+++ b/mcx/qsharp/MultiControlX.qs
@@ -1,6 +1,8 @@
 namespace ClassiqChallenge {
     open Microsoft.Quantum.Intrinsic;
     open Microsoft.Quantum.Canon;
+    open Microsoft.Quantum.Convert;
+    open Microsoft.Quantum.Diagnostics;
 
     // Programs for the MCX gate
 
@@ -9,8 +11,11 @@ namespace ClassiqChallenge {
         // Simple implementation of the Multi-Controlled X gate
         Controlled X(controlRegister, target);
     }
-    
-    @EntryPoint()
+
+    internal function XOR(a : Bool, b : Bool) : Bool {
+        return (a and not b) or (b and not a);
+    }
+
     operation ApplyMultiControlledX(initControl : Bool, initTarget : Bool) :
     Result {
         let controlRegisterSize = 14;
@@ -30,6 +35,10 @@ namespace ClassiqChallenge {
         apply {
             MultiControlledX(controlRegister, target);
         }
+
+        let expectedResult = BoolAsResult(XOR(initControl, initTarget));
+        AssertQubit(expectedResult, target);
+
         return M(target);
     }
 
diff --git a/mcx/qsharp/ResourcesEstimator.cs b/mcx/qsharp/ResourcesEstimator.cs
new file mode 100644
index 0000000..8db26e8
--- /dev/null
+++ b/mcx/qsharp/ResourcesEstimator.cs
@@ -0,0 +1,64 @@
+using System;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+using Microsoft.Quantum.Simulation.Simulators.QCTraceSimulators;
+using ClassiqChallenge;
+
+namespace host
+{
+    static class Program
+    {
+        static int DefaultPrimitiveDepth = 1;
+
+        // See:
+        // https://docs.microsoft.com/en-us/dotnet/api/microsoft.quantum.simulation.simulators.qctracesimulators.qctracesimulatorconfiguration
+        static QCTraceSimulatorConfiguration GetConfig()
+        {
+            var config = new QCTraceSimulatorConfiguration();
+            config.UseWidthCounter = true;
+            config.UseDepthCounter = true;
+
+            // Optimize for using less qubits
+            config.OptimizeDepth = false;
+
+            // Configure depth counting:
+            // Count every relevant primitive in the depth metric.
+            // By default only T primitives are counted, i.e. the depth is T-depth.
+            foreach (var primitive in new List<PrimitiveOperationsGroups>{
+                PrimitiveOperationsGroups.CNOT,
+                PrimitiveOperationsGroups.QubitClifford,
+                PrimitiveOperationsGroups.R,
+                PrimitiveOperationsGroups.T,
+                }
+            )
+            {
+                config.TraceGateTimes[primitive] = DefaultPrimitiveDepth;
+            }
+            // Do not count measurements - they are only helpers in this case.
+            config.TraceGateTimes[PrimitiveOperationsGroups.Measure] = 0;
+
+            foreach (var kvp in config.TraceGateTimes)
+            {
+                Console.WriteLine(kvp);
+            }
+            return config;
+        }
+
+        // See:
+        // https://docs.microsoft.com/en-us/azure/quantum/machines/qc-trace-simulator/width-counter
+        static async Task Main(string[] args)
+        {
+            var sim = new QCTraceSimulator(GetConfig());
+
+            var singleQubitResult = await ApplyMultiControlledX.Run(
+                sim, initControl: false, initTarget: false
+            );
+
+            double width = sim.GetMetric<ApplyMultiControlledX>(MetricsNames.WidthCounter.ExtraWidth);
+            double depth = sim.GetMetric<ApplyMultiControlledX>(MetricsNames.DepthCounter.Depth);
+
+            Console.WriteLine($"Single qubit result: {singleQubitResult}");
+            Console.WriteLine($"Width: {width}, Depth: {depth}.");
+        }
+    }
+}