Re: [Rails-devel] Several answers related to revenue calculation

[alexti <al...@sh...>]

Hi Stefan,

Thanks for the information. I agree that if we want to track down  
evaluation count differences it will be better to start from a single 2 or  
3 train run.

Alex.

On Thu, 22 Apr 2010 14:43:34 -0600, Stefan Frey (web.de)  
<ste...@we...> wrote:

> Hi Alex,
> answers to several raised question in various e-mails.
>
> And btw:
> The calculation class (RevenueCalculator) is plain Java 1.0 and depends  
> on no
> other class (neither Java API, nor JGraph, nor Rails), except the
> RevenueAdapter to allow callbacks for intermediate revenue updates.
>
> Also the data structure is strongly simplified, vertexes, edges and  
> trains are
> stored as their required attributes in int / boolean arrays.
>
> All the setup is down by the  RevenueAdapter.
>
> In fact the process is that first from the Rails classes the already more
> generic classes NetworkVertex, NetworkEdge and NetworkTrain are  
> generated.
> Those are then used to populate the arrays of the RevenueCalculator.
>
> Simply check the latest version at:
> http://rails.cvs.sourceforge.net/viewvc/rails/18xx/rails/algorithms/RevenueCalculator.java
>
> Stefan
>
>> Yeah, I even can construct a case with 4D and 5 train in 18AL where it's
>> better to run 4D only instead of running both trains. I need to add  
>> "null"
>> route into consideration. Stefan, would you implementation be affected  
>> by
>> the same issue?
>
> That is not an issue for my implementation: A route can merely exist on a
> route to the start token only. However the route is considered of value  
> zero,
> unless two stations are included. Steve Undy raised a similar question:
>
>> BTW, in my trying out the CVS version I saw the route calculation  
>> running
>> "excess" trains with a route including just one city.
>>
>
> Currently the route printout does not adjust the value of each station  
> to the
> actual value. This effects express trains and double trains as well.
>
>> I think that I have identical procedure, but when you say you evaluate
>> train set at (4), and let's say you have 2 trains, does it increase
>> evaluation count by 1 or by 2? I count it as 2 evaluations. In practice  
>> I
>> keep results of evaluation of the first train while trying possible  
>> routes
>> for the second train.
>
> I changed my code somewhat that changed all of the numbers a little (at  
> least
> with revenue calculation). It could have changed the number of the brute
> force approach, as I believe I removed one optimization, which would not  
> work
> anymore if general bonus/malus rules are included.
>
>> I've investigated number of evaluations a bit, mostly looking into a
>> single train case as it has few affecting factors. I've confirmed that  
>> all
>> 5601 possible routes in 8 train scan are unique. However, there are only
>> 2460 unique city sequences. Total number (5601) is greater because it's
>> often possible to run exactly the same sequence of cities while using
>> somewhat different track. Of course, neither number matches yours. Do  
>> you
>> have any ideas about the cause of discrepancy?
>
> To be more precise I only evaluate after running the last train and each
> evaluation is single counted, regardless of  the number of trains in the
> train set. My suggestion if we want to really find the difference in the
> counts to start with running a two and/or three train in scenario A,  
> cases
> which are easier to enumerate manually.
>
>> I believe I have both optimizations you mentioned. Just to be clear on  
>> (2)
>> - for example, if the candidate route starts at the station and is 7
>> cities long while only 6-trains are available it won't be evaluated,  
>> right?
>
> Yes that is right.
>
>
>
>
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