Q# Simulation Behavior

Question

I am attempting to run a series of tests on a Q# program I'm running on the local simulator, but I'm not seeing any way to use >1 shot and collect the results of those shots at once, as in essentially every other quantum language/system I've seen. Is this not a feature at all in the Q#/Azure Quantum system? Thank you!

Answer 1

Thanks for your question! If you're interested in running multiple shots of a quantum operation, Q# allow for doing that with conventional programming techniques such as a for loop:

open Microsoft.Quantum.Arrays;
open Microsoft.Quantum.Measurement;

operation SampleRandomBit() : Result {
    using (q = Qubit()) {
        return MResetX(q);
    }
}

operation SampleManyRandomBits(nBits : Int) : Result[] {
    mutable results = EmptyArray<Result>();
    for (_ in 1..nBits) {
        set results += [SampleRandomBit()];
    }
    return results;
}

The Q# standard library also provides some convenience operations for repeating operations in this way, such as DrawMany or EstimateFrequency:

open Microsoft.Quantum.Characterization;

operation SampleManyRandomBits(nBits : Int) : Result[] {
    return DrawMany(SampleRandomBit, nBits, ());
}

operation EstimateHeadsProbability(nShots : Int) : Double {
    return EstimateFrequency(ApplyToEach(H, _), Measure([PauliZ], _), 1, nShots);
}