A Three-Stage Saving-Based Heuristic for Vehicle Routing Problem with Time Windows and Stochastic Travel Times

Algorithm 3

The procedure to calculate the evaluation value of a top-layer point denoted by saving from the depth layer of the data structure.

(1) Function calculateEvaluationValue(Saving, Depth):

(2)  Set Depth = Depth − 1;

(3)  Connect the pair of customers in Saving;

(4)  Set TotalValue = 0, TotalValueNumber = 0;

(5)  While there is any saving in the saving list that has not been considered, do:

(6)   Fetch a saving from saving list into Sav;

(7)   If the pair of customers in Sav can be connected without violating any problem constraint, do:

(8)    If depth > 0, do:

(9)     Call function calculateEvaluationValue(Sav, depth) and get the evaluation value of Sav, denoted by SavEv;

(10)    Set TotalValue = TotalValue + SavEv, TotalValueNumber = TotalValueNumber + 1;

(11)    Elseif depth = 0, do:

(12)     Set the evaluation value of Sav, denoted by SavEv, to its saving value;

(13)     Set TotalValue = TotalValue + SavEv, TotalValueNumber = TotalValueNumber + 1;

(14)    Endif;

(15)  Endwhile;

(16)  If TotalValueNumber > 0, set SavingEv = TotalValue/TotalValueNumber;

(17)  Disconnect the pair of customers in Saving;

(18) Return SavingEv.