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quantum-computingq#

MeasureAllZ result comparison

use (qn, q2) = (Qubit[n], Qubit());
.....
let result = MeasureAllZ(qn);
if (result != Zero) {
    set isConstant = false;
}

I have this very simple q# snippet. When I try to run it on Azure using IonQ I got the following error

Microsoft.Quantum.Providers.Core.Processor.CannotCompareMeasurementResultException: Measurement results cannot be compared to Zero or One on the target architecture

How do I fix it?

Solution

  • IonQ targets in Azure Quantum don't support mid-circuit measurement: measurement has to be the last thing your code does, and it has to return the measurement results immediately. In your case, try doing return MeasureAllZ(qn); right away.