Function applyMultiStateControlledDiagMatrPower

quest/src/api/operations.cpp:394–425

}

void applyMultiStateControlledDiagMatrPower(Qureg qureg, int* controls, int* states, int numControls, int* targets, int numTargets, DiagMatr matrix, qcomp exponent) {
    validate_quregFields(qureg, __func__);
    validate_controlsAndTargets(qureg, controls, numControls, targets, numTargets, __func__);
    validate_controlStates(states, numControls, __func__); // can be nullptr, ignoring numControls
    validate_matrixDimMatchesTargets(matrix, numTargets, __func__);
    validate_matrixIsUnitary(matrix, __func__); 
    validate_matrixExpIsNonDiverging(matrix, exponent, __func__);
    validate_unitaryExponentIsReal(exponent, __func__);

    // unlike calcExpecDiagMatrPower which accepts a 'qreal' exponent,
    // this function accepts a 'qcomp'. This is because it always
    // evaluates the relatively numerically unstable pow(qcomp,qcomp)
    // overload, rather than pow(qreal,qreal), since there is no reason
    // to think matrix is real (unitarity permits it to be complex).
    // As such, despite unitarity requiring exponent is also real, we
    // accept a qcomp types so that complex exponents can be passed
    // when numerical validation is disabled without a separate func.

    bool conj = false;
    auto ctrlVec = util_getVector(controls, numControls);
    auto stateVec = util_getVector(states,  numControls); // empty if states==nullptr
    auto targVec = util_getVector(targets,  numTargets);
    localiser_statevec_anyCtrlAnyTargDiagMatr(qureg, ctrlVec, stateVec, targVec, matrix, exponent, conj);

    if (!qureg.isDensityMatrix)
        return;

    conj = true;
    ctrlVec = util_getBraQubits(ctrlVec, qureg);
    targVec = util_getBraQubits(targVec, qureg);
    localiser_statevec_anyCtrlAnyTargDiagMatr(qureg, ctrlVec, stateVec, targVec, matrix, exponent, conj);
}

} // end de-mangler