Step 3 : Are all equations fulfilled and is optimality reached? Initial values for the optimization variables can for example be obtained using a shortcut method. A possibility for multiple dividing wall columns has been presented by . In these works a V min diagram is used to approximate the minimal amount of vapor needed to achieve the separation of the substances under consideration assuming an infinite number of stages. An improved approximation in the case of a finite number of stages has been developed by Ränger and Grützner 2021. However, in Section 5.2 we investigate the influence of the starting values on the result. The experiments show that the approach is very robust and often converges to an optimal solution even for a random choice of initial values. Nevertheless a good choice of initial values can improve the convergence rate.