// Parses MCF wavefunction.
internal static SparseMultiCFWavefunction <SpinOrbital> ToSparseMultiCFWavefunction(List <List <string> > superposition)
{
var outputState = new SparseMultiCFWavefunction <SpinOrbital>();
// Todo: modify broombridge to have explicit reference state.
foreach (var element in superposition)
{
// First item is the amplitude.
double amplitude = double.Parse(element.First().ToString(), System.Globalization.CultureInfo.InvariantCulture);
// Second to Second-last are fermion operators.
IEnumerable <LadderOperator <SpinOrbital> > operators = element
.Take(element.Count() - 1)
.Skip(1)
.Select(o => V0_1.ParsePolishNotation(o.ToString()));
var ladderSequence = new LadderSequence <SpinOrbital>(operators);
// Sort operators to index order.
IEnumerable <IndexOrderedSequence <SpinOrbital> > sortedOperators = ladderSequence.ToIndexOrder();
// Only select the shortest term with no repeated indices.
IndexOrderedSequence <SpinOrbital> sortedOperator = sortedOperators.ToList().OrderBy(o => o.UniqueIndices()).First();
outputState.Set(sortedOperator, new Complex(amplitude, 0.0));
}
return(outputState);
}
/// <summary>
/// Builds Hamiltonian from Broombridge if data is available.
/// </summary>
internal static OrbitalIntegralHamiltonian ToOrbitalIntegralHamiltonian(ProblemDescription broombridge)
{
// Add the identity terms
var identityterm = broombridge.CoulombRepulsion.Value + broombridge.EnergyOffset.Value;
var hamiltonian = V0_1.ToOrbitalIntegralHamiltonian(broombridge.Hamiltonian);
hamiltonian.Add(new OrbitalIntegral(), identityterm);
return(hamiltonian);
}
// Parses UCC wavefunction.
internal static UnitaryCCWavefunction <SpinOrbital> ToUnitaryCCWavefunction(ClusterOperator clusterOperator)
{
var outputState = new UnitaryCCWavefunction <SpinOrbital>();
var oneBodyTerms = clusterOperator.OneBodyAmplitudes ??
new List <List <string> >();
var twoBodyTerms = clusterOperator.TwoBodyAmplitudes ??
new List <List <string> >();
foreach (var element in oneBodyTerms.Concat(twoBodyTerms))
{
// First item is the amplitude.
double amplitude = double.Parse(element.First().ToString(), System.Globalization.CultureInfo.InvariantCulture);
// Second to last are fermion operators.
IEnumerable <LadderOperator <SpinOrbital> > operators = element
.Skip(1)
.Select(o => V0_1.ParsePolishNotation(o.ToString()));
var ladderSequence = new LadderSequence <SpinOrbital>(operators);
// Terms are assumed to be in normal order.
var sortedOperator = new IndexOrderedSequence <SpinOrbital>(operators);
outputState.Set(sortedOperator, new Complex(amplitude, 0.0));
}
var reference = new List <List <string> >()
{
clusterOperator.Reference
};
outputState.Reference = new SingleCFWavefunction <SpinOrbital>(
ToSparseMultiCFWavefunction(reference).Excitations.Single().Key.ToIndices()
);
return(outputState);
}