Method setTarget

python/utils/LinkedLibraryHolder.cpp:424–520

}

void LinkedLibraryHolder::setTarget(
    const std::string &targetName,
    std::map<std::string, std::string> extraConfig) {
  // Do not set the default target if the disallow
  // flag has been set.
  if (!cudaq::detail::canModifyTarget())
    return;

  auto iter = targets.find(targetName);
  if (iter == targets.end())
    throw std::runtime_error("Invalid target name (" + targetName + ").");

  auto &target = iter->second;
  if (!target.config.WarningMsg.empty()) {
    fmt::print(fmt::fg(fmt::color::red), "[warning] ");
    // Output the warning message if any
    fmt::print(fmt::fg(fmt::color::blue), "Target {}: {}\n", target.name,
               target.config.WarningMsg);
  }
  const std::string targetConfigStr =
      cudaq::config::processRuntimeArgs(target.config, extraConfig);
  parseRuntimeTarget(cudaqLibPath, target, targetConfigStr);

  CUDAQ_INFO("Setting target={} (sim={}, platform={})", targetName,
             target.simulatorName, target.platformName);
  std::string simName = target.simulatorName;
  if (simName.empty()) {
    // This target doesn't have a simulator defined, e.g., hardware targets.
    // We still need a simulator in case of local emulation.
    // Ensure defaultTarget is fully resolved (it may still be the initial
    // "qpp-cpu" if deferred initialization hasn't run yet).
    defaultTarget = resolveDefaultTarget();
    auto &defaultTargetInfo = targets[defaultTarget];
    simName = defaultTargetInfo.simulatorName;

    // The precision should match the underlying local simulator that we
    // selected.
    target.precision = defaultTargetInfo.precision;

    // This is really a user error: e.g., using `CUDAQ_DEFAULT_SIMULATOR`
    // environment variable (meant for simulator) to change the default target
    // to some other targets that are not a simulator.
    if (simName.empty())
      throw std::runtime_error("Default target " + defaultTarget +
                               " doesn't define a simulator. Please check your "
                               "CUDAQ_DEFAULT_SIMULATOR environment variable.");
  }
  __nvqir__setCircuitSimulator(getSimulator(simName));
  auto *platform = getPlatform(target.platformName);

  // Provide the already-parsed target config so that
  // DefaultQuantumPlatform::setTargetBackend can skip re-reading the YAML.
  platform->runtimeTarget = std::make_unique<cudaq::RuntimeTarget>(target);

  // Pack the config into the backend string name
  std::string backendConfigStr = targetName;
  auto potentialServerHelperPath =
      cudaqLibPath /