Adding operator* method

Signed-off-by: Sachin Pisal <[email protected]>

Author: sacpis

runtime/cudaq/cudm_state.h

@@ -99,6 +99,10 @@ class cudm_state {
   /// @return The new state after multiplying scalar with the current state.
   cudm_state &operator*=(const std::complex<double> &scalar);
 
+  cudm_state operator*(double scalar) &&;
+
+  double norm() const;
+
 private:
   std::vector<std::complex<double>> rawData_;
   std::complex<double> *gpuData_;

runtime/cudaq/dynamics/cudm_state.cpp

@@ -181,6 +181,21 @@ cudm_state &cudm_state::operator*=(const std::complex<double> &scalar) {
   return *this;
 }
 
+cudm_state cudm_state::operator*(double scalar) && {
+  this->operator*=(scalar);
+  return std::move(*this);
+}
+
+double cudm_state::norm() const {
+  std::vector<std::complex<double>> rawData = this->get_raw_data();
+
+  double norm = 0.0;
+  for (const auto &val : rawData) {
+    norm += std::norm(val);
+  }
+  return std::sqrt(norm);
+}
+
 std::string cudm_state::dump() const {
   if (!is_initialized()) {
     throw std::runtime_error("State is not initialized.");