public override void Assert(IQArray <Pauli> bases, IQArray <Qubit> qubits, Result expected, string msg)
{
Qubit?filter(Pauli p, Qubit q) =>
p switch
{
Pauli.PauliI => null,
Pauli.PauliZ => q,
_ => throw new InvalidOperationException("Assert on bases other than PauliZ not supported")
};
// All qubits are considered whose corresponding measurement basis
// is PauliZ. Measurement in PauliI basis are ignored, and other
// bases will raise an exception.
var qubitsToMeasure = bases.Zip(qubits, filter).WhereNotNull();
// A multi-qubit measurement in the PauliZ basis corresponds to
// computing the parity of all involved qubits' measurement values.
// (see also https://docs.microsoft.com/quantum/concepts/pauli-measurements#multiple-qubit-measurements)
// We use Aggregate to successively XOR a qubit's simulation value
// to an accumulator value `accu` that is initialized to `false`.
var actual = qubitsToMeasure.Aggregate(false, (accu, qubit) => accu ^ GetValue(qubit));
if (actual.ToResult() != expected)
{
// If the expected value does not correspond to the actual measurement
// value, we throw a Q# specific Exception together with the user
// defined message `msg`.
throw new ExecutionFailException(msg);
}
}
}
public virtual long StartConditionalStatement(IQArray <Result> results1, IQArray <Result> results2)
{
if (results1 == null)
{
return(results2 == null ? 1 : 0);
}
;
if (results1.Count != results2?.Count)
{
return(0);
}
;
return(results1.Zip(results2, (r1, r2) => (r1, r2)).Any(pair => pair.r1 != pair.r2) ? 0 : 1);
}
/// <summary>
/// The implementation of the operation.
/// For the Toffoli simulator, the implementation returns the joint parity of the
/// states of the measured qubits.
/// That is, Result.One is returned if an odd number of the measured qubits are
/// in the One state.
/// </summary>
public Result Measure__Body(IQArray <Pauli> paulis, IQArray <Qubit> targets)
{
Qubit?f(Pauli p, Qubit q) =>
p switch
{
Pauli.PauliI => null,
Pauli.PauliZ => q,
_ => throw new InvalidOperationException($"The Toffoli simulator can only Measure in the Z basis.")
};
if (paulis.Length != targets.Length)
{
throw new InvalidOperationException($"Both input arrays for Measure (paulis, targets), must be of same size");
}
var qubitsToMeasure = paulis.Zip(targets, f).WhereNotNull();
var result = this.GetParity(qubitsToMeasure);
return(result.ToResult());
}
}