Encog.MathUtil.LIBSVM.Solver.do_shrinking C# (CSharp) Method

        internal virtual void do_shrinking()
        {
            int i, j, k;
            var working_set = new int[2];
            if (select_working_set(working_set) != 0)
                return;
            i = working_set[0];
            j = working_set[1];
            double Gm1 = (- y[j])*G[j];
            double Gm2 = y[i]*G[i];

            // shrink

            for (k = 0; k < active_size; k++)
            {
                if (is_lower_bound(k))
                {
                    if (y[k] == + 1)
                    {
                        if (- G[k] >= Gm1)
                            continue;
                    }
                    else if (- G[k] >= Gm2)
                        continue;
                }
                else if (is_upper_bound(k))
                {
                    if (y[k] == + 1)
                    {
                        if (G[k] >= Gm2)
                            continue;
                    }
                    else if (G[k] >= Gm1)
                        continue;
                }
                else
                    continue;

                --active_size;
                swap_index(k, active_size);
                --k; // look at the newcomer
            }

            // unshrink, check all variables again before final iterations

            if (unshrinked || - (Gm1 + Gm2) > eps*10)
                return;

            unshrinked = true;
            reconstruct_gradient();

            for (k = l - 1; k >= active_size; k--)
            {
                if (is_lower_bound(k))
                {
                    if (y[k] == + 1)
                    {
                        if (- G[k] < Gm1)
                            continue;
                    }
                    else if (- G[k] < Gm2)
                        continue;
                }
                else if (is_upper_bound(k))
                {
                    if (y[k] == + 1)
                    {
                        if (G[k] < Gm2)
                            continue;
                    }
                    else if (G[k] < Gm1)
                        continue;
                }
                else
                    continue;

                swap_index(k, active_size);
                active_size++;
                ++k; // look at the newcomer
            }
        }