// Converts JSON to data format with existing Q# pipeline
// Input: JSON file
// Output: PauliHamiltonian for later use in Q# pipeline
public static PauliHamiltonian CallQSharpPipeline(
JObject OptimizedHamiltonian,
int index
)
{
// make Hamiltonian to be output
var hamiltonian = new PauliHamiltonian();
// Pull the interactions from a specific round
var interactionList = OptimizedHamiltonian["terms"]["interactions"][index];
// make the conversion function
Func <FermionTerm, TermType.Fermion, double, IEnumerable <(PauliTerm, PauliTermValue)> > conversion =
(fermionTerm, termType, coeff)
=> (fermionTerm.ToJordanWignerPauliTerms(termType, coeff));
// pull the interactions and parse them into the PauliHamiltonian format
foreach (var interaction in interactionList)
{
var(term, type, coeffData) = ConvertToFermionFormat(interaction);
hamiltonian.AddRange(conversion(term, type, coeffData));
// if ((string)interaction["type"] == "Identity")
// {
// // We need to still add the term if it's an identity term
// hamiltonian.
// } else {
// var (term, type, coeff) = ConvertToFermionFormat(interaction);
// hamiltonian.AddRange(conversion(term, type, coeff));
// }
}
// assume that the indices are simply an ascending 0-indexed list
List <int> indices = new List <int>();
for (int i = 0; i < interactionList.Count(); i++)
{
indices.Add(i);
}
hamiltonian.SystemIndices = new HashSet <int>(indices);
// hamiltonian.SystemIndices = new HashSet<int>(sourceHamiltonian.SystemIndices.ToList());
return(hamiltonian);
}
/// <summary>
/// Method for constructing a Pauli Hamiltonian from a fermion Hamiltonina.
/// </summary>
/// <param name="sourceHamiltonian">Input orbital integral Hamiltonian.</param>
/// <param name="encoding">Identifies how the terms should be encoded on the qubits.</param>
/// <returns>Fermion Hamiltonian constructed from orbital integrals.</returns>
public static PauliHamiltonian ToPauliHamiltonian(
this FermionHamiltonian sourceHamiltonian,
QubitEncoding encoding = QubitEncoding.JordanWigner)
{
var nFermions = sourceHamiltonian.SystemIndices.Max() + 1;
var hamiltonian = new PauliHamiltonian();
Func <FermionTerm, TermType.Fermion, double, IEnumerable <(PauliTerm, PauliTermValue)> > conversion =
(fermionTerm, termType, coeff)
=> (fermionTerm.ToJordanWignerPauliTerms(termType, coeff));
foreach (var termType in sourceHamiltonian.Terms)
{
foreach (var term in termType.Value)
{
hamiltonian.AddRange(conversion(term.Key, termType.Key, term.Value.Value));
}
}
// Create a copy of fermion indices hash set.
hamiltonian.SystemIndices = new HashSet <int>(sourceHamiltonian.SystemIndices.ToList());
return(hamiltonian);
}