diff --git a/WHATS_NEW.md b/WHATS_NEW.md index da8f3830..c715f6c2 100644 --- a/WHATS_NEW.md +++ b/WHATS_NEW.md @@ -3,14 +3,44 @@ WHATS NEW ------------------------------ 2014-03-?? new release **v1.6** +When reviewing the feedback from our users, we realized that jsprit cannot solve certain kinds of problems adequately. +To illustrate and characterize them, look at the following examples. + +jsprit, which was basically specific configurations of the schrimpf-algorithm was/is good and fast at solving this: + ![schrimpf_simpleCluster](https://github.com/jsprit/misc-rep/raw/master/wiki-images/vrp_clustered_schrimpf_simpleCluster.png) +The algorithm results in what we expect by looking at the problem. Look at what happened when we add similar job-clusters +between depot and the existing clusters. + ![schrimpf_moreClusters](https://github.com/jsprit/misc-rep/raw/master/wiki-images/vrp_clustered_schrimpf_moreClusters.png) +Obviously, the way we ruined and recreated wasn't sufficient to solve the problem reasonably. +To make it even more obvious, we added a number of job cloud surrounding + the depot. The schrimpf-algorithm (as we configured it) yields the following solution. + ![schrimpf_moreClusters_depotNoise](https://github.com/jsprit/misc-rep/raw/master/wiki-images/vrp_clustered_schrimpf_moreClusters_depotNoise.png) +This is definitely not the intuitive solution, one would expect when looking at the problem sharply. + +Therefore, we put much effort into analysing this and designing a new algorithm (which is still based on the +schrimpf principles). We implemented two new ruin strategies: worst and cluster ruin, and we added +noise to the ruin and recreation strategies. Moreover, the new algorithm makes use of regretInsertion by default. +On all benchmarking instances, our new algorithm performs better (or at least as good + as) than the previous algorithms in terms of solution quality. However, it comes with higher computational costs. +Look at how the new algorithm solves the above problem + ![schrimpf_moreClusters_depotNoise](https://github.com/jsprit/misc-rep/raw/master/wiki-images/vrp_clustered_jsprit_moreClusters_depotNoise.png) +which is the intuitive solution. Along with this we made a number of incremental changes to simplify the implementation +which, in turn, makes your life easier when designing your own algorithm. + +The second major improvement is that we changed the way locations are defined. Instead of separately assigning location-id and coordinates, +we encapsulated these attributes in an object called Location. It is not only clearer, but it +allows you to assign a location index. Thus, you can save the transport times and distances +between locations in (fast) arrays rather than maps (see FastVehicleRoutingTransportCostMatrix). + + ------------------------------ 2014-12-12 new release **v1.5**