Add Measure Function

Author: adamisntdead

src/helper.cpp

@@ -0,0 +1,22 @@
+#include <arrayfire.h>
+#include <random>
+
+int select(af::array weights) {
+    // Assumes sum of the weights are 1
+
+    std::random_device rd;
+    std::mt19937 gen(rd());
+    std::uniform_real_distribution<> dis(0.0, 1.0);
+    float key = dis(gen);
+
+    int index = 0;
+    for (; index < weights.dims(0); index++) {
+        key = key - weights(index).scalar<float>();
+
+        if (key <= 0) {
+            return index;
+        }
+    }
+
+    return index;
+}

src/helper.h

@@ -0,0 +1,7 @@
+#ifndef HELPER_H_INCLUDED
+#define HELPER_H_INCLUDED
+#include <arrayfire.h>
+
+int select(af::array weights);
+
+#endif

src/main.cpp

@@ -2,19 +2,22 @@
 
 #include "kron.h"
 #include "gates.h"
+#include "helper.h"
 
 using namespace af;
 
 class QuantumRegister {
     private:
        array amplitudes;
+       int numQubits;
        bool measured = false;
     public:
-        QuantumRegister(int numQubits) {
+        QuantumRegister(int n) {
+            numQubits = n;
             // The number of amplitudes needed is 2^n = 2 << (n - 1),
             // Where N is the number of qubits. The constant(0, n) function
             // Creates an array of n 0s
-            amplitudes = constant(0, 2 << (numQubits - 1), c32);
+            amplitudes = constant(0, 2 << (n - 1), c32);
             // Set the probability of getting all zeros when measured to 1
             amplitudes(0) = 1;
         }
@@ -23,28 +26,21 @@ class QuantumRegister {
             amplitudes = matmul(gate, amplitudes);
         }
 
-        array measure() {
+        int measure() {
             array probabilities = pow(abs(amplitudes), 2);
-            af_print(probabilities);
 
-            return probabilities;
+            return select(probabilities);
         }
 };
 
-void run() {
-    QuantumRegister q(20);
-    //q.applyGate(Gates::H);
-
-    q.measure();
-
-    return;
-}
-
 int main(int argc, char **argv) {
     // af::info();
-    //QuantumRegister q(2);
-    //q.measure();
-    af_print(kron(Gates::X, Gates::Id));
+    int count = 0;
+
+    QuantumRegister q(1);
+    q.applyGate(Gates::H);
+    count += q.measure();
+    
 
     return 0;
 }