Function applyForcedMultiQubitMeasurement

quest/src/api/operations.cpp:1698–1716

}

qreal applyForcedMultiQubitMeasurement(Qureg qureg, int* qubits, int* outcomes, int numQubits) {
    validate_quregFields(qureg, __func__);
    validate_targets(qureg, qubits, numQubits, __func__);
    validate_measurementOutcomesAreValid(outcomes, numQubits, __func__);

    auto qubitVec = util_getVector(qubits, numQubits);
    auto outcomeVec = util_getVector(outcomes, numQubits);

    // ensure probability of the forced measurement outcome is not negligible
    qreal prob = calcProbOfMultiQubitOutcome(qureg, qubits, outcomes, numQubits); // harmlessly re-validates
    validate_measurementOutcomesProbNotZero(outcomes, numQubits, prob, __func__);

    // project to the outcome, renormalising the surviving states
    (qureg.isDensityMatrix)?
        localiser_densmatr_multiQubitProjector(qureg, qubitVec, outcomeVec, prob):
        localiser_statevec_multiQubitProjector(qureg, qubitVec, outcomeVec, prob);

    return prob;
}

} // end de-mangler