private void grad(IElementalAccessMatrix dy, IElementalAccessVector x)
{
IElementalAccessVector y0 = new DenseVector(x.Length);
IElementalAccessVector y = new DenseVector(x.Length);
model(y0, x);
for (int i = 0; i < x.Length; i++)
{
x.AddValue(i, 0.000001);
model(y, x);
for (int j = 0; j < x.Length; j++)
{
dy.SetValue(j, i, (y.GetValue(j) - y0.GetValue(j)) / 0.000001);
}
x.AddValue(i, -0.000001);
}
}
/// <summary> Assembly using addValue</summary>
/// <param name="nu">Maximum number of entries
/// </param>
/// <returns> Dense representation (not a direct copy)
/// </returns>
public static double[] addAssembleVector(IElementalAccessVector x, int nu)
{
int n = x.Length;
double[] data = new double[n];
System.Random r = new System.Random();
for (int i = 0; i < nu; ++i)
{
int ind = TesterUtilities.getInt(n, r);
double entry = r.NextDouble();
data[ind] += entry;
x.AddValue(ind, entry);
}
return(data);
}