Configuring the FullStateSimulator

Before a quantum_kernel can be called, a properly configured instance of the FullStateSimulator class is required. This can be done by creating an IqsConfig object with the desired values and passing it to the constructor or initializer of the FullStateSimulator. The type QRT_ERROR_T is used to check-on the status of simulator instance. For example,

// configure to use N qubits; accepts defaults for remaining
iqsdk::IqsConfig iqs_config(/*num_qubits*/ N);

// setup quantum device
iqsdk::FullStateSimulator iqs_device(iqs_config);
iqs_device.printVerbose(true);

// ensure setup was successful
if (iqsdk::QRT_ERROR_SUCCESS != iqs_device.ready()) return 1;

The essential classes and methods for configuration are detailed below. See API Reference for the full list of APIs to find details about retrieving data.

Overview of FullStateSimulator

Class with API calls to both set up a quantum simulator device and access the underlying quantum state during simulation.

• Constructor

  FullStateSimulator(IqsConfig &device_config);
  

  Instantiates a simulator object that is initialized to the settings in device_config.

• printVerbose()

  QRT_ERROR_T FullStateSimulator::printVerbose(bool printVerbose);
  

  Sets the status of the simulator’s verbose output.

• ready()

  QRT_ERROR_T FullStateSimulator::ready();
  

  Returns an enum of QRT_ERROR_T; QRT_ERROR_SUCCESS if the simulator is ready to run a quantum_kernel, else returns QRT_ERROR_FAIL. Ensure the simulator is ready before executing quantum_kernel functions or making any queries.

  Provides a trigger for opportunities to define error handling logic.

Execution Options

The Intel® Quantum SDK backends have two execution modes:

• Synchronous (default): pauses the execution of the program whenever a QBB is called. Execution resumes once the QBB is done running.

• Asynchronous: the host puts the QBB into a queue of QBBs to be run.

Prior to using the results of any measurements, the user should call wait() on the device to ensure that the device has finished running and set the appropriate cbit(s). Any API that sets a device property (e.g. setting contraction path method) is put on the queue, while any API that gets simulation data from the device blocks until the device has finished running.

The synchronous parameter in the DeviceConfig specifies whether the backend will run in synchronous or asynchronous mode. Other backends such as Clifford Simulator, Tensor Network Simulator, and a user-defined Custom Backend can also utilize the asynchronous execution mode for faster simulations.

Overview of IqsConfig

Class to hold configuration data used to configure the FullStateSimulator or user-defined qubit simulator backend.

• Constructor

  IqsConfig(int num_qubits = 1,
             std::string simulation_type = "noiseless",
             bool verbose = false,
             std::size_t seed = time(NULL),
             bool synchronous = true,
             double depolarizing_rate = 0.01);
  

  Specify configuration data for the IQS. Creates an IqsConfig which has the following properties:

  int num_qubits:

  Number of qubits in simulation.

  std::string simulation_type:

  Type of simulation to be run. Valid simulation types are: "noiseless", "depolarizing", and "custom". See Customizable Noise Modeling for details on the "custom" option.

  std::size_t seed:

  Custom seed for RNG. If no seed is provided, the current time will be used as the seed.

  double depolarizing_rate:

  Depolarizing rate for noisy simulation.

• isValid()

  bool IqsConfig::isValid();
  

  Returns whether the given config instance is valid.