func (r *RegularizingCost) Cost(a linalg.Vector, x autofunc.Result) autofunc.Result { regFunc := autofunc.SquaredNorm{} cost := r.CostFunc.Cost(a, x) for _, variable := range r.Variables { norm := regFunc.Apply(variable) cost = autofunc.Add(cost, autofunc.Scale(norm, r.Penalty)) } return cost }