Probabilities

Functions for non-destructively calculating the probabilities of measurement outcomes. More...

Functions
qreal	calcProbOfBasisState (Qureg qureg, qindex index)
qreal	calcProbOfMultiQubitOutcome (Qureg qureg, int *qubits, int *outcomes, int numQubits)
qreal	calcProbOfQubitOutcome (Qureg qureg, int qubit, int outcome)
void	calcProbsOfAllMultiQubitOutcomes (qreal *outcomeProbs, Qureg qureg, int *qubits, int numQubits)

Detailed Description

Functions for non-destructively calculating the probabilities of measurement outcomes.

Function Documentation

calcProbOfBasisState()

qreal calcProbOfBasisState	(	Qureg	qureg,
		qindex	index )

Note

Documentation for this function or struct is under construction!

Attention

This function's input validation has not yet been tested, so erroneous usage may produce unexpected output. Please use with caution!

Definition at line 219 of file calculations.cpp.

                                                      {
    validate_quregFields(qureg, __func__);
    validate_basisStateIndex(qureg, index, __func__);
 
    // |i><i| = ||(1+2^N)i>>
    if (qureg.isDensityMatrix)
        index *= 1 + powerOf2(qureg.numQubits);
 
    qcomp amp = localiser_statevec_getAmp(qureg, index);
    qreal prob = (qureg.isDensityMatrix)? 
        std::real(amp): 
        std::norm(amp);
 
    return prob;
}

Referenced by TEST_CASE().

calcProbOfMultiQubitOutcome()

qreal calcProbOfMultiQubitOutcome	(	Qureg	qureg,
		int *	qubits,
		int *	outcomes,
		int	numQubits )

Note

Documentation for this function or struct is under construction!

Attention

This function's input validation has not yet been tested, so erroneous usage may produce unexpected output. Please use with caution!

Definition at line 246 of file calculations.cpp.

                                                                                          {
    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);
 
    return (qureg.isDensityMatrix)?
        localiser_densmatr_calcProbOfMultiQubitOutcome(qureg, qubitVec, outcomeVec):
        localiser_statevec_calcProbOfMultiQubitOutcome(qureg, qubitVec, outcomeVec);
}

Referenced by applyForcedMultiQubitMeasurement(), calcProbOfQubitOutcome(), and TEST_CASE().

calcProbOfQubitOutcome()

qreal calcProbOfQubitOutcome	(	Qureg	qureg,
		int	qubit,
		int	outcome )

Note

Documentation for this function or struct is under construction!

Attention

This function's input validation has not yet been tested, so erroneous usage may produce unexpected output. Please use with caution!

Definition at line 236 of file calculations.cpp.

                                                                  {
    validate_quregFields(qureg, __func__);
    validate_target(qureg, qubit, __func__);
    validate_measurementOutcomeIsValid(outcome, __func__);
 
    int numQubits = 1;
    return calcProbOfMultiQubitOutcome(qureg, &qubit, &outcome, numQubits);
}

Referenced by applyForcedQubitMeasurement(), applyQubitMeasurementAndGetProb(), and TEST_CASE().

calcProbsOfAllMultiQubitOutcomes()

void calcProbsOfAllMultiQubitOutcomes	(	qreal *	outcomeProbs,
		Qureg	qureg,
		int *	qubits,
		int	numQubits )

Note

Documentation for this function or struct is under construction!

Attention

This function's input validation has not yet been tested, so erroneous usage may produce unexpected output. Please use with caution!

Definition at line 260 of file calculations.cpp.

                                                                                                    {
    validate_quregFields(qureg, __func__);
    validate_targets(qureg, qubits, numQubits, __func__);
    validate_measurementOutcomesFitInGpuMem(qureg, numQubits, __func__);
 
    auto qubitVec = util_getVector(qubits, numQubits);
 
    (qureg.isDensityMatrix)?
        localiser_densmatr_calcProbsOfAllMultiQubitOutcomes(outcomeProbs, qureg, qubitVec):
        localiser_statevec_calcProbsOfAllMultiQubitOutcomes(outcomeProbs, qureg, qubitVec);
}

Referenced by applyMultiQubitMeasurementAndGetProb(), and TEST_CASE().