11. Quantum Platform

CUDA Quantum provides an abstraction describing the underlying quantum computing resource(s). The underlying quantum platform can contain one or many quantum processing units (QPUs) each with its own qubit connectivity and noise configuration.

CUDA Quantum defines a cudaq::quantum_platform in an effort to expose relevant system information and enable asynchronous quantum kernel invocations.

The cudaq::quantum_platform provides an API for querying the number of available quantum processing units (QPUs), with each QPU assigned a logical integer index ({0,1,2,...}). Programmers can specify the ID of the desired QPU and all subsequent CUDA Quantum kernel executions will target that QPU.

The cudaq::quantum_platform should take the following structure

namespace cudaq {
  class quantum_platform {
  public:
    quantum_platform();
    ~quantum_platform();

    using QubitEdge = std::pair<std::size_t, std::size_t>;
    using QubitConnectivity = std::vector<QubitEdge>;
    std::optional<QubitConnectivity> connectivity();

    std::size_t num_qpus() const;
    std::size_t get_num_qubits(std::size_t qpu_id = 0) const;

    bool is_simulator(std::size_t qpu_id = 0) const;
    bool is_remote(std::size_t qpuId = 0);
    std::string name() const;

    std::size_t get_current_qpu() const ;
    void set_current_qpu(const std::size_t device_id);

  };
}

CUDA Quantum provides the following public functions to interact with the current cudaq::quantum_platform

namespace cudaq {
  quantum_platform &get_platform() ;
}