private Matrix[] CalcGreenFunction(TightBindingSuite.TightBinding tb, RpaParams p, KptList kmesh)
{
int orbitalCount = tb.Orbitals.Count;
Matrix[] retval = new Matrix[kmesh.Kpts.Count];
Complex denomFactor = new Complex(0, p.Temperature);
for (int k = 0; k < kmesh.Kpts.Count; k++)
{
retval[k] = new Matrix(orbitalCount, orbitalCount);
Matrix hamilt = tb.CalcHamiltonian(kmesh.Kpts[k].Value);
Matrix vals, vecs;
hamilt.EigenValsVecs(out vals, out vecs);
for (int i = 0; i < orbitalCount; i++)
{
for (int j = 0; j < orbitalCount; j++)
{
for (int n = 0; n < orbitalCount; n++)
{
var wfk = new Wavefunction(orbitalCount);
wfk.Energy = vals[n, 0].RealPart;
for (int c = 0; c < vecs.Rows; c++)
{
wfk.Coeffs[c] = vecs[c, n];
}
Complex coeff =
wfk.Coeffs[i].Conjugate() *
wfk.Coeffs[j];
Complex g = 1.0 / (p.Frequency + p.ChemicalPotential - wfk.Energy + denomFactor);
retval[k][i, j] += g * coeff;
}
}
}
}
return retval;
}
private void WriteGreenFunctionPlane(TightBindingSuite.TightBinding tb, Matrix[] green, KptList kmesh)
{
Console.WriteLine("Output as a plane.");
Console.WriteLine();
Console.WriteLine("Enter vectors as a series of three numbers, like: 1 1 0");
Console.WriteLine("Only integer values need be used.");
Console.WriteLine();
Console.Write("Enter first vector: ");
string first = Console.ReadLine();
if (string.IsNullOrEmpty(first))
return;
Console.Write("Enter second vector: ");
string second = Console.ReadLine();
Vector3 sdir = Vector3.Parse(first);
Vector3 tdir = Vector3.Parse(second);
Vector3 udir = Vector3.CrossProduct(sdir, tdir);
Console.Write("Enter origin point: ");
string origin = Console.ReadLine();
Vector3 orig = Vector3.Parse(origin);
Vector3 closestKpt = Vector3.Zero;
double closestDistance = 999999999;
foreach (var kpt in kmesh.AllKpts)
{
double distance = (kpt.Value - orig).MagnitudeSquared;
if (distance < closestDistance)
{
closestKpt = kpt.Value;
closestDistance = distance;
}
}
if (closestDistance > 1e-6)
{
Console.WriteLine("Using closest k-point to specified origin: {0}.", closestKpt);
orig = closestKpt;
sdir += closestKpt;
tdir += closestKpt;
}
KptList plane = KptList.GeneratePlane(
tb.Lattice, new Vector3[] { orig, sdir, tdir }, tb.Symmetries, kmesh);
string tr_filename = string.Format("green.tr.pln");
StreamWriter tr = new StreamWriter(tr_filename);
double lastt = double.MinValue;
for (int k = 0; k < plane.AllKpts.Count; k++)
{
Complex trValue = new Complex();
for (int i = 0; i < green[k].Rows; i++)
{
trValue += green[k][i, i];
}
Vector3 kpt = plane.AllKpts[k].Value;
List<int> orbitalMap;
double s, t;
plane.GetPlaneST(plane.AllKpts[k], out s, out t);
int kindex = kmesh.IrreducibleIndex(kpt, tb.Lattice, tb.Symmetries, out orbitalMap);
if (Math.Abs(t - lastt) > 1e-6)
{
tr.WriteLine();
lastt = t;
}
tr.WriteLine("{0}\t{1}\t{2}", s, t, -trValue.ImagPart);
}
tr.Close();
for (int i = 0; i < green[0].Rows; i++)
{
for (int j = 0; j < green[0].Columns; j++)
{
string re_filename = string.Format("green.re.{0}.{1}.pln", i,j);
string im_filename = string.Format("green.im.{0}.{1}.pln", i, j);
string mag_filename = string.Format("green.mag.{0}.{1}.pln", i, j);
StreamWriter rew = new StreamWriter(re_filename);
StreamWriter imw = new StreamWriter(im_filename);
StreamWriter mag = new StreamWriter(mag_filename);
try
{
lastt = double.MaxValue;
for (int k = 0; k < plane.AllKpts.Count; k++)
{
Vector3 kpt = plane.AllKpts[k].Value;
List<int> orbitalMap;
double s, t;
plane.GetPlaneST(plane.AllKpts[k], out s, out t);
int kindex = kmesh.IrreducibleIndex(kpt, tb.Lattice, tb.Symmetries, out orbitalMap);
if (Math.Abs(t - lastt) > 1e-6)
{
rew.WriteLine();
imw.WriteLine();
mag.WriteLine();
lastt = t;
}
rew.WriteLine("{0}\t{1}\t{2}", s, t, green[kindex][i, j].RealPart);
imw.WriteLine("{0}\t{1}\t{2}", s, t, -green[kindex][i, j].ImagPart);
mag.WriteLine("{0}\t{1}\t{2}", s, t, green[kindex][i, j].Magnitude);
}
}
finally
{
rew.Dispose();
imw.Dispose();
mag.Dispose();
}
}
}
}
private void WriteGreenFunction(TightBindingSuite.TightBinding tb, Matrix[] green, KptList kmesh)
{
WriteGreenFunctionPlane(tb, green, kmesh);
}
