/// <summary>
/// Computes the percentage of weakly diagonally dominant rows/columns
/// </summary>
private void DiagonalDominant()
{
int n = S.RowCount;
var ax = S.Values;
var ap = S.RowPointers;
var ai = S.ColumnIndices;
var rwork = new double[n];
var cwork = new double[n];
var dwork = new double[n];
int i, j, k, end;
double a, b, max = 0.0;
double fnorm = 0.0; // Frobenius norm
for (i = 0; i < n; i++)
{
end = ap[i + 1];
for (k = ap[i]; k < end; k++)
{
j = ai[k];
a = math.Abs(ax[k]);
fnorm += math.Square(ax[k]);
if (j == i)
{
dwork[i] = a;
}
else
{
rwork[i] += a;
cwork[j] += a;
}
max = Math.Max(max, a);
}
}
int ddomc = 0; // number of weakly diagonally dominant columns
int ddomr = 0; // number of weakly diagonally dominant rows
a = b = 0.0;
for (i = 0; i < n; i++)
{
if (cwork[i] <= dwork[i])
{
ddomc++;
}
if (rwork[i] <= dwork[i])
{
ddomr++;
}
a = Math.Max(rwork[i] + dwork[i], a); // Infinity norm
b = Math.Max(cwork[i] + dwork[i], b); // 1-norm
}
var info = this.StorageInfo;
info.DiagonallyDominantRows = ddomr;
info.DiagonallyDominantColumns = ddomc;
info.MaxAbsoluteValue = max;
info.FrobeniusNorm = Math.Sqrt(fnorm);
info.InfNorm = a;
info.OneNorm = b;
}
