//! compute value of the least square function
public override double value(Vector x)
{
// size of target and function to fit vectors
Vector target = new Vector(lsp_.size());
Vector fct2fit = new Vector(lsp_.size());
// compute its values
lsp_.targetAndValue(x, ref target, ref fct2fit);
// do the difference
Vector diff = target - fct2fit;
// and compute the scalar product (square of the norm)
return(Vector.DotProduct(diff, diff));
}
