public override void Setup(IMatrix A)
{
int n = A.RowCount;
diag = new double[n];
diagInd = new int[n];
// Get the diagonal and its indices
if (A is ISparseRowAccessMatrix)
{
for (int i = 0; i < n; ++i)
{
IntDoubleVectorPair Arow = ((ISparseRowAccessMatrix)A).GetRow(i);
int ind = Array.BinarySearch(Arow.indices, i);
if (ind < 0)
{
throw new ArgumentException("Diagonal not present");
}
diag[i] = Arow.data[ind];
diagInd[i] = ind;
}
}
else if (A is ISparseRowColumnAccessMatrix)
{
IntIntDoubleVectorTriple Amat = ((ISparseRowColumnAccessMatrix)A).Matrix;
for (int i = 0; i < n; ++i)
{
int ind = Arrays.binarySearch(Amat.major, i, Amat.minor[i], Amat.minor[i + 1]);
if (ind < 0)
{
throw new ArgumentException("Diagonal not present");
}
diag[i] = Amat.data[ind];
diagInd[i] = ind;
}
}
else if (A is IDenseRowColumnAccessMatrix)
{
IntDoubleVectorPair Amat = ((IDenseRowColumnAccessMatrix)A).Matrix;
for (int i = 0; i < n; ++i)
{
diagInd[i] = Amat.indices[i] + i;
diag[i] = Amat.data[diagInd[i]];
}
}
else if (A is IDenseRowAccessMatrix)
{
for (int i = 0; i < n; ++i)
{
double[] Arow = ((IDenseRowAccessMatrix)A).GetRow(i);
diagInd[i] = i;
diag[i] = Arow[i];
}
}
else
{
throw new NotSupportedException();
}
}
private void ssor(ISparseRowColumnAccessMatrix A, double[] xdata)
{
int n = A.RowCount;
IntIntDoubleVectorTriple Amat = A.Matrix;
// M = (D+L) D^{-1} (D+L)^T
// Solves (1/omega)*(D+L) y = b
for (int i = 0; i < n; ++i)
{
// Do nothing if we get a divide by zero
if (Math.Abs(diag[i]) == 0.0)
{
continue;
}
double sum = 0;
for (int j = Amat.minor[i]; j < Amat.minor[i + 1] && Amat.major[j] < i; ++j)
{
sum += Amat.data[j] * xdata[Amat.major[j]];
}
xdata[i] = (omega / diag[i]) * (xdata[i] - sum);
}
// Solves (omega/(2-omega))*D^{-1} z = y
for (int i = 0; i < n; ++i)
{
// No need to do anything
if (Math.Abs(diag[i]) == 0.0)
{
continue;
}
xdata[i] = (2 - omega) / omega * diag[i] * xdata[i];
}
// Solves (1/omega)*(D+L)^T x = z
for (int i = n - 1; i >= 0; --i)
{
// Do nothing if we get a divide by zero
if (Math.Abs(diag[i]) == 0.0)
{
continue;
}
double sum = 0;
for (int j = diagInd[i] + 1; j < Amat.minor[i + 1]; ++j)
{
sum += Amat.data[j] * xdata[Amat.major[j]];
}
xdata[i] = (omega / diag[i]) * (xdata[i] - sum);
}
}
private void sor(ISparseRowColumnAccessMatrix A, double[] bdata, double[] xdata)
{
IntIntDoubleVectorTriple Amat = A.Matrix;
for (int i = 0; i < A.RowCount; ++i)
{
double newVal = 0, diagVal = 0.0;
for (int j = Amat.minor[i]; j < Amat.minor[i + 1]; ++j)
{
if (Amat.major[j] != i)
{
newVal += Amat.data[j] * xdata[Amat.major[j]];
}
else
{
diagVal = Amat.data[j];
}
}
newVal = (bdata[i] - newVal) / diagVal;
xdata[i] += omega * (newVal - xdata[i]);
}
}
private void gaussSeidel(ISparseRowColumnAccessMatrix A, double[] bdat, double[] xdat)
{
IntIntDoubleVectorTriple Amat = A.Matrix;
for (int i = 0; i < A.RowCount; ++i)
{
double newVal = 0, diagVal = 0.0;
for (int j = Amat.minor[i]; j < Amat.minor[i + 1]; ++j)
{
if (Amat.major[j] != i)
{
newVal += Amat.data[j] * xdat[Amat.major[j]];
}
else
{
diagVal = Amat.data[j];
}
}
xdat[i] = (bdat[i] - newVal) / diagVal;
}
}
