Implemented Accelerator:retrieve()

Signed-off-by: Daniel Claudino <claudinodc@ornl.gov>

quantum/plugins/ibm/accelerator/IBMAccelerator.cpp

@@ -349,6 +349,22 @@ void IBMAccelerator::cancel() {
   }
 }
 
+void IBMAccelerator::retrieve(const std::string jobId, std::shared_ptr<xacc::AcceleratorBuffer> buffer) {
+
+  const std::string path("/runtime/jobs/" + jobId + "/results");
+  auto resultsJson = get(IBM_API_URL, path, headers);
+  auto hexs = json::parse(resultsJson)["results"][0]["data"]["q_c"]["samples"];
+
+  std::vector<int> samples;
+  for (const auto& sample_hex : hexs) {
+            int sample_int = std::stoi(sample_hex.get<std::string>(), nullptr, 16);
+            // Convert the integer to a binary string
+            samples.push_back(sample_int);
+        }
+        buffer->setSamples(samples);
+  return;
+}
+
 std::vector<std::pair<int, int>> IBMAccelerator::getConnectivity() {
 
   if (!xacc::container::contains(availableBackends, backend)) {

quantum/plugins/ibm/accelerator/IBMAccelerator.hpp

@@ -15,15 +15,11 @@
 #define QUANTUM_GATE_ACCELERATORS_IBMACCELERATOR_HPP_
 
 #include "InstructionIterator.hpp"
-//#include "Properties.hpp"
 #include "Accelerator.hpp"
 #include <bitset>
 #include <type_traits>
-//#include "Backends.hpp"
-//#include "Properties.hpp"
 #include "IRTransformation.hpp"
 #include "Json.hpp"
-//#include "QObjGenerator.hpp"
 
 using namespace xacc;
 using json = nlohmann::json;
@@ -73,6 +69,7 @@ std::string hex_string_to_binary_string(std::string hex);
 class IBMAccelerator : public Accelerator {
 public:
   void cancel() override;
+  void retrieve(const std::string jobId, std::shared_ptr<xacc::AcceleratorBuffer> buffer) override;
 
   std::map<std::string, std::map<int, int>> name2QubitMap;
 

xacc/accelerator/Accelerator.hpp

@@ -108,6 +108,7 @@ class Accelerator : public Identifiable {
   }
 
   virtual void cancel(){};
+  virtual void retrieve(const std::string jobId, std::shared_ptr<xacc::AcceleratorBuffer> buffer){};
 
   virtual std::vector<std::pair<int, int>> getConnectivity() {
     return std::vector<std::pair<int, int>>{};

xacc/accelerator/AcceleratorBuffer.cpp

@@ -21,6 +21,22 @@
 
 using namespace rapidjson;
 
+std::string intToBinary(int num, const int nBits) {
+
+    std::string binary;
+    while (num > 0) {
+        binary.insert(0, 1, (num & 1) ? '1' : '0');
+        num >>= 1;
+    }
+
+    // Pad with leading zeros to ensure minimum bit width
+    if (binary.size() < nBits) {
+        binary.insert(0, nBits - binary.size(), '0');
+    }
+
+    return binary;
+}
+
 namespace xacc {
 
 bool CheckEqualVisitor::operator()(const int &i) const {
@@ -754,4 +770,25 @@ void AcceleratorBuffer::load(std::istream &stream) {
   }
 }
 
+void AcceleratorBuffer::setSample(const int sample) {
+
+  auto bitString = intToBinary(sample, size());
+  appendMeasurement(bitString);
+  _samples.push_back(sample);
+}
+
+void AcceleratorBuffer::setSamples(const std::vector<int> samples) {
+  for (auto s : samples) {
+    setSample(s);
+  }
+}
+
+int AcceleratorBuffer::getSample(const int index) {
+  return _samples[index];
+}
+
+std::vector<int> AcceleratorBuffer::getSamples() {
+  return _samples;
+}
+
 } // namespace xacc

xacc/accelerator/AcceleratorBuffer.hpp

@@ -118,6 +118,7 @@ class HeterogenousMap2ExtraInfo
 class AcceleratorBuffer {
 
 protected:
+  std::vector<int> _samples;
   std::map<std::string, int> bitStringToCounts;
   std::string bufferId;
   int nBits;
@@ -268,6 +269,11 @@ class AcceleratorBuffer {
     return getInformation(key);
   }
 
+  void setSample(const int sample);
+  void setSamples(const std::vector<int> samples);
+  int getSample(const int index);
+  std::vector<int> getSamples();
+
   virtual ~AcceleratorBuffer() {}
 };