Race Schedules & Software

Debates and discussions on the various race scheduling methods that can be used and their fairness and accuracy in determining the winners.
theDoc
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Race Schedules & Software

Post by theDoc » Tue Oct 12, 2010 8:45 am

Hey guys,

I am the PWD chair for the second year in our pack, last year being my first. We have a large pack (about 100 boys this year, 60-80 will race usually), and I want the fairest scheduling that I can provide. I know you need a lot more info, so here's everything:

We weight in on a Friday night and have the Leaders/Adults/Sibling race during this time so that the boys have something to watch (the LAS cars get qualified and impounded during the previous den meetings).

The boys race against their dens on Saturday and the top 3 from each den race for overall winners.

We have a 2 lane track and score by win or lose (1 or 0 points).

In the previous years we have used a scheduling system someone found that is an excel spreadsheet. But I would like to change it. I would like every car to race all other cars twice, once in each lane. I know it will take forever but I think all PWD chairs know that parents get upset that their kid didn't place because they didn't race the "slow car" or they raced all the "fast cars" or other complaints. So this year we will have a longer race, but a fairer race.

So is there a scheduling chart to do this with, or maybe even some software to schedule and score the races, that way the human math error is eliminated? Or am I asking for a miracle?

Thanks in advance



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Stan Pope
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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 9:31 am

Congratulations! It takes a big man (or woman) to voluntarily become the target of so many arrows.

You are describing a "double round robin" competition. This is one of the possible outputs from the PPN Chart Generator (http://www.stanpope.net/ppngen.html), where the "Number of Cars" is set to be the smallest odd number greater than or equal to the actual number of cars in the den and the "Number of Rounds" is one less.

Examples:
1. Den of 6 racers: Number of Cars = 7, Number of Rounds = 6
2. Den of 7 racers: Number of Cars = 7, Number of Rounds = 6
3. Den of 8 racers: Number of Cars = 9, Number of Rounds = 8

The web page has a "scorekeeper option", but a better choice is to use either one of the packages that incorporates the generation code, such as Randy Lisano's GPRM, or Cory Young's Excel spreadsheet (see http://members.cox.net/pinehead/software.html) that likewise incorporates the generation code.


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Re: Race Schedules & Software

Post by gpraceman » Tue Oct 12, 2010 9:32 am

That sounds like a double Round Robin schedule. The problem with Round Robin scheduling is that the number of heats goes up exponentially as you increase the number of racers.

You may want to consider Complimentary Perfect-N (CPN) scheduling. Some race management software can generate these, as well as this web based generator. Though, you need the right number of racers and not quite sure if you can get these charts for a two lane track.

EDIT: Looks like Stan beat me to the punch.


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 9:45 am

Sorry 'bout that, Randy! :)

The PPN Generator for 2 lane tracks was not originally intended to generate double round robin schedules. That was a "happy coincidence." Had that been a goal, we would have included charts for an even number of cars rather than requiring the mental gymnastics and bye's.

For den size groups, typically 8 racers or fewer, the number of heats is more or less manageable:
Number of Heats = Number of Cars * Number of Rounds
= Number of Cars * (Number of Cars -1)


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 10:33 am

Note that there is a difference in terminology between the PPN web page and GPRM:

PPN defines one round as each car running once in each lane.

IIRC, GPRM defines one round as each car running once.

Use the definition of the software with which you are interfacing.


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Re: Race Schedules & Software

Post by theDoc » Tue Oct 12, 2010 11:44 am

So I am looking for Complimentary Perfect N, as far as I can tell from the links you guys provided. I also checked out the free excel spreadsheet, but it only supports 4 rounds and all my dens have more than 10 boys that are planning on racing. I also saw the pages on the formulas to make your own...but I almost passed out so I had to close those.

Software wise, what is available? Free or pay, we are a big enough pack that a little expense doesn't break us.

Thanks again



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Re: Race Schedules & Software

Post by gpraceman » Tue Oct 12, 2010 12:17 pm

Stan Pope wrote:PPN defines one round as each car running once in each lane.

IIRC, GPRM defines one round as each car running once.
Actually, GPRM defines a "Round" as being the whole schedule for a group. Within a round, racers can run one or more times down each lane of the track. What you define as a round is more how GPRM defines a "run per lane".


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 12:29 pm

GPRM is indexed in the commercial area of DerbyTalk. Randy tries to keep his "for sale" hat on a different rack from most of DerbyTalk's content. GPRM is a sound product with bells and whistles options beyond the basic race management functionality. I think that it is worth the nominal cost.

re: definition of round. Perhaps I misunderstood Randy's comment some months (years?) ago. I'm sure of y description of PPN's use of "round". It is derived from the application of one "generator vector" which produces as many heats as there are racers. Each racer runs once in each lane, and, therefore, races once in Lane 1.

Randy, If I described GPRM incorrectly, please set me straight.


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 12:43 pm

theDoc wrote:... and all my dens have more than 10 boys that are planning on racing.
Are you dividing by "Den" (e.g. Den 1, Den 2, ...) or by "age group" (e.g. Tiger, Wolf, Bear, ...)?

Double round robin is tenable for "den size" groups, but not always for "age group" size groups, especially when the pack gets above 40 boys!

If you find that a full "double round robin" is not tenable, then use fewer rounds. In any case, be sure to match racers to the chart randomly, e.g. draw racer name and chart number from a hat. That prevents an appearance of manipulation. Any advantage or disadvantage related to who races whom and when is then pure chance.

The next best choice after "double round robin" is a "single round robin", which requires 1/2 as many heats. Everybody still races everybody, but the "lane swap aspect is removed. It is slightly less accurate than a double round robin, but still very good.


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Re: Race Schedules & Software

Post by gpraceman » Tue Oct 12, 2010 2:32 pm

A GrandPrix Race Manager (GPRM) user sent me a set of round robin charts for a two lane track, based on varying numbers of cars. It would be easy enough to make these double round robin. Just copy what is there, paste to the bottom and then go and swap the lane 1 and lane 2 assignments, for what was pasted. Once that is done, they can be easily imported into GPRM (and maybe some other race software that can import from a text file).

You can download those charts from http://grandprix-race-central.com/downl ... Charts.zip.


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 4:06 pm

gpraceman wrote: It would be easy enough to make these double round robin. Just copy what is there, paste to the bottom and then go and swap the lane 1 and lane 2 assignments, for what was pasted. Once that is done, they can be easily imported into GPRM (and maybe some other race software that can import from a text file).

You can download those charts from http://grandprix-race-central.com/downl ... Charts.zip.
Randy,

Those RR charts for an even number of racers are of poor quality.
They do not satisfy the basic PPN requirement for Lane Equality. As such, you would not want to use them for timed racing and, perhaps, not for points racing.

Concatenation of a lane-swapped replica to make them "double round robin" does restore Lane Equality, I think.

My sampling of those charts for an odd number of racers are good quality, apparently identical in match-ups as those produced by the PPN chart generator.


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Re: Race Schedules & Software

Post by gpraceman » Tue Oct 12, 2010 4:16 pm

Stan Pope wrote:They do not satisfy the basic PPN requirement for Lane Equality.
I agree that any single round robin will likely not guarantee lane equity.

As with any scheduling method, there are pros and cons that should be examined to determine what is the best fit for an organization. Personally, I wouldn't run with a round robin schedule unless the race groups are sufficiently small (don't want it to take forver to run all those heats) and the lane equity issue can be addressed for varying numbers of racers (no "bad lane" draw argument).


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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 5:07 pm

gpraceman wrote:
Stan Pope wrote:They do not satisfy the basic PPN requirement for Lane Equality.
I agree that any single round robin will likely not guarantee lane equity.
The "odd number of racers" charts do have lane equity, at least the ones that I inspected. If, as it appears, they were acquired from running ppngen.htm and selecting the "simulation input" format as output, then all would have lane equity, as the "by round" heat generation method used by ppngen automatically produces lane equity.


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Re: Race Schedules & Software

Post by theDoc » Tue Oct 12, 2010 8:18 pm

Stan Pope wrote:
theDoc wrote:... and all my dens have more than 10 boys that are planning on racing.
Are you dividing by "Den" (e.g. Den 1, Den 2, ...) or by "age group" (e.g. Tiger, Wolf, Bear, ...)?

Double round robin is tenable for "den size" groups, but not always for "age group" size groups, especially when the pack gets above 40 boys!

If you find that a full "double round robin" is not tenable, then use fewer rounds. In any case, be sure to match racers to the chart randomly, e.g. draw racer name and chart number from a hat. That prevents an appearance of manipulation. Any advantage or disadvantage related to who races whom and when is then pure chance.

The next best choice after "double round robin" is a "single round robin", which requires 1/2 as many heats. Everybody still races everybody, but the "lane swap aspect is removed. It is slightly less accurate than a double round robin, but still very good.


I am dividing the groups by den (tigers, wolves, bears, etc). We have more boys this year than last and I think the smallest group racing was 10 and the largest was 15-18. But like I said, these numbers might double in a den.

I would prefer that each boy race each other once in each lane (2 lane track).

Sorry I sound redundant, I might not understand your question.

So I apparently missed something, what's the difference between double round robin and complimentary perfect n?

Thanks again guys, this site is amazing!



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Re: Race Schedules & Software

Post by Stan Pope » Tue Oct 12, 2010 11:58 pm

theDoc wrote: I am dividing the groups by den (tigers, wolves, bears, etc). We have more boys this year than last and I think the smallest group racing was 10 and the largest was 15-18. But like I said, these numbers might double in a den.
...
Sorry I sound redundant, I might not understand your question.
Okay, if I understand correctly that you want all of the tiger cubs to race in one group and all of the wolf cubs to race in one group, etc. then I would have expressed it as "age group" or "rank group". "Den" is an organizational unit. Large packs often have more than one Tiger Den and more than one Wolf Den etc. This is done so that each den leader has a managable number of den members to work with. When my mother was a den leader (called a "den mother" at that time), she would have gone crazy with more than 8 of us Bear Cubs meeting in her kitchen or basement each week! :)

So, if you have 100 Cubs, you probably have 25 to 30 each Tiger age, Wolf age and Bear age. Unless you den leaders are imbued with great powers, they probably have divided the Tigers into smaller groups of 7 to 9 boys for each of 3 or 4 den leaders. Same for the Wolf cubs, etc.
theDoc wrote:So I apparently missed something, what's the difference between double round robin and complimentary perfect n?
"Double round robin" is usually used to describe one-on-one competitions, e.g. chess tournaments. At higher levels, double round robin is preferred so that each player plays both white and black pieces against each of his opponents.

For two lane tracks CPN and Double Round Robin are equivalent. CPN applies to tracks with any number of lanes, but the underlying concept of the two terms are identical.

During the development of PPN I had not made the association between the two since I was mostly thinking in terms of typical 3 and 4 lane tracks. Co-author Cory may have recognized the assonciation, but, if so, he said nothing to me about it. Anyway, we just added on to the PN name to qualify the original name to describe the added or loosened criteria which the charts satisfied.


Stan
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