What type of scheduling?

Debates and discussions on the various race scheduling methods that can be used and their fairness and accuracy in determining the winners.
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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 6:01 am

Stan Pope wrote:As I understand, "Phase shift" is equivalent to the underlying heat generation process of PPN. The difference is that the racer number delta between lanes starts out larger than the current PPN deltas. If you use "phase shift", you may unintentionally produce greater variance in opponent equity and, as a result, loose the points ranking - times ranking correlation.
Okay looking at a sample 40-2 (3 round) PPN which produces 120 heats, I see that you start with a 1-12 generator for the first 28 heats, then go to a 28-1 generator, then 1-11, 29-1, 1-10, 30-1.

Are you saying that the difference is that "Phase Shift" would start with a generator with a larger delta such as a 1-18? Can you explain in the simplest terms how this "may unintentionally produce greater variance in opponent equity and, as a result, loose the points ranking - times ranking correlation".

gpraceman, can you explain what the difference would be between a Phase shifted Lane rotation schedule and a PPN schedule that tries to keep heat counts even, avoids cars in consecutive races and cars in the same lanes in consecutive races for 40 cars running 3 rounds (120 heats) on a two lane track? Or could you email examples schedules so that I could compare?



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Re: What type of scheduling?

Post by gpraceman » Tue Oct 26, 2010 7:43 am

*5 J's* wrote:gpraceman, can you explain what the difference would be between a Phase shifted Lane rotation schedule and a PPN schedule that tries to keep heat counts even, avoids cars in consecutive races and cars in the same lanes in consecutive races for 40 cars running 3 rounds (120 heats) on a two lane track? Or could you email examples schedules so that I could compare?
A Phase Shifted Lane Rotation chart is basically a regular Lane Rotation chart where a shift of the numbers has been applied to each of the lanes (except lane 1). The amount of the shift is dependent on the number of cars and number of lanes, but GPRM will tweak that shift amount, if need be, to achieve a workable chart.

Here's a quick example of a Phase Shifted chart from GPRM (4 lanes, 9 cars and 1 run per lane):

1 8 6 5
2 9 7 6
3 1 8 7
4 2 9 8
5 3 1 9
6 4 2 1
7 5 3 2
8 6 4 3
9 7 5 4

Phase Shifted LR charts meet all of the LR requirements (each lane used an equal number of times for each racer, cars will run in a different lane for each run). There is no consideration taken for cars in consecutive heats. Phase Shifted charts do a better job with opponent count than other types of LR charts, but not as good as PPN type charts in many cases. The main advantage of the Phase Shifted charts over PPN type is that it is very easy to predict what cars are going to be in the next heat (n + 1 of those in current heat), so you can stage cars more quickly.


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 8:06 am

gpraceman wrote:Phase Shifted LR charts meet all of the LR requirements (each lane used an equal number of times for each racer, cars will run in a different lane for each run). There is no consideration taken for cars in consecutive heats. Phase Shifted charts do a better job with opponent count than other types of LR charts, but not as good as PPN type charts in many cases. The main advantage of the Phase Shifted charts over PPN type is that it is very easy to predict what cars are going to be in the next heat (n + 1 of those in current heat), so you can stage cars more quickly.
Thanks Randy. It sounds like PPN may be best then, as I really don't need to predict what cars are going to be in the next heat, especially considering GPRM can display racers "on deck".



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Re: What type of scheduling?

Post by gpraceman » Tue Oct 26, 2010 8:13 am

*5 J's* wrote:Thanks Randy. It sounds like PPN may be best then
I do recommend PPN type schedules in most cases, since they do the best job at maximizing opponent count.
*5 J's* wrote:... I really don't need to predict what cars are going to be in the next heat, especially considering GPRM can display racers "on deck".
I do recommend that you print out the schedule, once generated, and give that to your staging crew. That way they are not depending on the On Deck display, as that is not always in view (heat winner is displayed there right after a heat is run). With a printout, the crew can also stage multiple heats ahead.


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 8:51 am

gpraceman wrote:
*5 J's* wrote:Thanks Randy. It sounds like PPN may be best then
I do recommend PPN type schedules in most cases, since they do the best job at maximizing opponent count.
*5 J's* wrote:... I really don't need to predict what cars are going to be in the next heat, especially considering GPRM can display racers "on deck".
I do recommend that you print out the schedule, once generated, and give that to your staging crew. That way they are not depending on the On Deck display, as that is not always in view (heat winner is displayed there right after a heat is run). With a printout, the crew can also stage multiple heats ahead.
Thanks - we don't really have a staging crew as all racers handle their own cars. It takes us a bit longer, but I cannot imagine having somebody staging a scouts car. If one was going to run a race that way you could just run it as a web broadcast and all the scouts could stay at home and watch the event.



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Re: What type of scheduling?

Post by gpraceman » Tue Oct 26, 2010 9:03 am

*5 J's* wrote:Thanks - we don't really have a staging crew as all racers handle their own cars. It takes us a bit longer, but I cannot imagine having somebody staging a scouts car. If one was going to run a race that way you could just run it as a web broadcast and all the scouts could stay at home and watch the event.
Well, you can still have someone pre-staging cars. That is, simply placing the cars running in the next heat in some tray or designated On Deck spot on the staging table. The racers can grab their car from that spot and then place it on the track. You can also label the On Deck spot with lane numbers, so the racer will know which lane to put their car on. Little things like that can save a lot of time over the course of the race.


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 9:26 am

gpraceman wrote:
*5 J's* wrote:Thanks - we don't really have a staging crew as all racers handle their own cars. It takes us a bit longer, but I cannot imagine having somebody staging a scouts car. If one was going to run a race that way you could just run it as a web broadcast and all the scouts could stay at home and watch the event.
Well, you can still have someone pre-staging cars. That is, simply placing the cars running in the next heat in some tray or designated On Deck spot on the staging table. The racers can grab their car from that spot and then place it on the track. You can also label the On Deck spot with lane numbers, so the racer will know which lane to put their car on. Little things like that can save a lot of time over the course of the race.
Very true - thanks for the suggestion Randy. Currently with only two lane racing the scouts are pretty fast at getting their car from the staging table to the correct lane pretty quickly, but I bet this will take a bit more time once we get our four lane track. At that point we may need to add a staging tray. I'm just not a big fan of anybody but the scouts touching the cars. I even instruct our starter to make sure the cars are staged correctly - but if there is an issue point it out to the scout to let him fix it. Last year a scout put a car on the track backwards. The starter wanted to fix it - but the scout informed that he wanted to run the car backwards. I would feel really bad if the track crew dropped a scouts car - ughhh.



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Re: What type of scheduling?

Post by gpraceman » Tue Oct 26, 2010 9:35 am

If you are not employing a staging crew, you can still use a printout of the schedule to help speed things up. Give it to the MC, so they can call up the On Deck racers. If the screen is not currently displaying the On Deck circle, the MC can look to the printout.


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Re: What type of scheduling?

Post by Stan Pope » Tue Oct 26, 2010 9:44 am

*5 J's* wrote:We only have 50 cubs in our pack, with 80% participation, I anticipate 40 entrants. I may run subgroups to award 1-3 ribbons to each age group, but I want all to run against each other for the top four positions as we need to send the top four to district competition.
Racing "everybody against everybody" (head to head) on a 2 lane track takes a lot of heats (40*39/2 = 780 heats, I think). However, you probably have time (2 to 3 hours) for 6 heats apiece (3*40 = 120 heats total) and can run with times. A good starting gate (spring open) will avoid most of the timing issues that I described. Still to avoid embarrassing errors, the results need to be "sanity checked" and the track operators need to be trained and have some practice before they start.
*5 J's* wrote:
Stan Pope wrote:As I understand, "Phase shift" is equivalent to the underlying heat generation process of PPN. The difference is that the racer number delta between lanes starts out larger than the current PPN deltas. If you use "phase shift", you may unintentionally produce greater variance in opponent equity and, as a result, loose the points ranking - times ranking correlation.
Okay looking at a sample 40-2 (3 round) PPN which produces 120 heats, I see that you start with a 1-12 generator for the first 28 heats, then go to a 28-1 generator, then 1-11, 29-1, 1-10, 30-1.

Are you saying that the difference is that "Phase Shift" would start with a generator with a larger delta such as a 1-18? Can you explain in the simplest terms how this "may unintentionally produce greater variance in opponent equity and, as a result, loose the points ranking - times ranking correlation".
Both use "modulus arithmetic" in generating heats. Modulus arithmetic gets its result using the remainder after division. It is equivalent (and simpler in this case) to just observe that when adding two numbers that are in the range 1-40 that if the sum exceeds 40, then subtract 40 (the number of racers) from the result. If a difference is less than one, add 40 to the result.

The example that you showed (1-12, 28-1 generators) are actually just one generator (12), i.e. the number of the lane 2 racer is 12 greater than the number of the lane 1 racer modulus 40. When, for instance, racer 29 races in lane 1, racer 1 (=29 + 13 - 40) races in lane 2.

Note that if I chose a generator of 20, in heat 1 racer 1 races against racer 21, and in heat 21 racer 1 races again against racer 21 but with lanes swapped. This creates an unsatisfactory imabalance in opponents: racing some twice while not racing others at all.

Those combinations are easy to avoid on 2 lanes, but are increasingly harder to avoid on 3, 4, and 5 lane tracks. The reason is that every two lane matchup presents the same problem. A 40 car 3 lane chart (generator = x,y) needs to avoid x = 20, y=20, and x+y=20. In addition, the generator needs to avoid x=y and x=-y. A 40 car 4 lane chart (generator = x,y,z) needs to avoid x=20, y=20, z=20, x+y=20, y+z=20, z+x=20, and x+y+z=20. In addition, the generator needs to avoid x=y, x=-y, x=z, x=-z, y=z, y=-z, x+y=y+z, x+y=-y-z, z+x=x+y, z+x=-x-y, (All "equals" relations interpreted using modulus arithmetic.)


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 10:11 am

Stan Pope wrote:Racing "everybody against everybody" (head to head) on a 2 lane track takes a lot of heats (40*39/2 = 780 heats, I think). However, you probably have time (2 to 3 hours) for 6 heats apiece (3*40 = 120 heats total) and can run with times. A good starting gate (spring open) will avoid most of the timing issues that I described. Still to avoid embarrassing errors, the results need to be "sanity checked" and the track operators need to be trained and have some practice before they start.
I wouldn't want to run 780 heats - that is the reason for not running PN or CPN. So the best "balance" to me, given our allotted time, is to run PPN 40-2 (3 rounds) such that each cars runs each lane 3 times or a total of 6 times. In the past we have had the cars run - then they immediately swap lanes and run again. This expedites the process, shows the audience a balance, but it's at the expense of limiting the number of match ups.

I am going to convert our old track to a spring open and it will be solenoid activated via GPRM. I hope to start my prototype tonight.

I agree that the data needs to have a sanity check. Perhaps I will run one of my tuned cars to get a FAST baseline - then have the computer operator be alert for any times that pass that threshold. Other than that is there any other considerations for avoiding embarrassing errors? The track operators should be removed from the equation if it is a solenoid activated spring open gate.
Stan Pope wrote:Both use "modulus arithmetic" in generating heats. Modulus arithmetic gets its result using the remainder after division. It is equivalent (and simpler in this case) to just observe that when adding two numbers that are in the range 1-40 that if the sum exceeds 40, then subtract 40 (the number of racers) from the result. If a difference is less than one, add 40 to the result.

The example that you showed (1-12, 28-1 generators) are actually just one generator (12), i.e. the number of the lane 2 racer is 12 greater than the number of the lane 1 racer modulus 40. When, for instance, racer 29 races in lane 1, racer 1 (=29 + 13 - 40) races in lane 2.

Note that if I chose a generator of 20, in heat 1 racer 1 races against racer 21, and in heat 21 racer 1 races again against racer 21 but with lanes swapped. This creates an unsatisfactory imabalance in opponents: racing some twice while not racing others at all.

Those combinations are easy to avoid on 2 lanes, but are increasingly harder to avoid on 3, 4, and 5 lane tracks. The reason is that every two lane matchup presents the same problem. A 40 car 3 lane chart (generator = x,y) needs to avoid x = 20, y=20, and x+y=20. In addition, the generator needs to avoid x=y and x=-y. A 40 car 4 lane chart (generator = x,y,z) needs to avoid x=20, y=20, z=20, x+y=20, y+z=20, z+x=20, and x+y+z=20. In addition, the generator needs to avoid x=y, x=-y, x=z, x=-z, y=z, y=-z, x+y=y+z, x+y=-y-z, z+x=x+y, z+x=-x-y, (All "equals" relations interpreted using modulus arithmetic.)
Ah, got it. My mathematics mind hasn't been adequately exercised for 20+ years. To think all that time in Calculus classes gone to waste....



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Re: What type of scheduling?

Post by pwrd by tungsten » Tue Oct 26, 2010 10:17 am

THey have Electronic Starting Systems that are really nice. I wonder if the race would speed up if you raced two cars and then raced a diffrent set of cars... I think it might...


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 10:32 am

gpraceman wrote:If you are not employing a staging crew, you can still use a printout of the schedule to help speed things up. Give it to the MC, so they can call up the On Deck racers. If the screen is not currently displaying the On Deck circle, the MC can look to the printout.
Yes - I will definitely print out a copy of the schedule for the MC and the Start Gate operator as well as a copy at the scoring table to manually record all times in the event of a computer hiccup.

Our Pack owns a copy of GPRM vre 2.0 but in the past they have just used it to capture elapsed time. The elapsed time is then manually entered into an Excel spreadsheet running two time trial rounds (two runs in each round for a total of four runs per car). After time trials the spreadsheet sets the top 16 up for a single elimination round. So aside from the poor scheduling, the lack of using GPRM features creates way to much passing of info between the MC, start gate, and computer operators - not to mention calling the scouts up to run. Heck, they could have used hyperterminal to get elapsed time from the timer. So I will definitely pass out the schedules so everybody has the program.

Anyway - in an effort to improve our program, I have downloaded a trial version of GPRM 10.0 and an familiarizing myself with it's operation and features. I have got thorough setup, registration, and am currently working thought scheduling - though I think I've got that now ;) . I have seen features that I am contemplating taking advantage of such as subgroups. I am chewing on creating a subgroup for each age group that would allow me to award 1-3 ribbons in each age group, then follow this with awarding the top 4 in the pack trophies. (I need to pick the top 4 to send to Districts). I am also thinking of getting pics of each scout to add to their profile. I think they would get a kick out of seeing their faces displayed on the big screen.

One additional question - does GPRM allow for an post race analysis that would allow seeing how the results compare if you used points racing vice avg time - or how it would compare if you through out the slowest run, etc.?



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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 10:34 am

pwrd by tungsten wrote:THey have Electronic Starting Systems that are really nice. I wonder if the race would speed up if you raced two cars and then raced a diffrent set of cars... I think it might...
PBT - I will be running a solenoid start gate triggered via GPRM. Is that what you are suggesting?



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Re: What type of scheduling?

Post by gpraceman » Tue Oct 26, 2010 10:51 am

*5 J's* wrote:One additional question - does GPRM allow for an post race analysis that would allow seeing how the results compare if you used points racing vice avg time - or how it would compare if you through out the slowest run, etc.?
Not really a comparison, but at any time you can switch from times to points and vice versa to see how the standings look. While in times scoring, you can turn on/off throwing out the worst time for each racer.
*5 J's* wrote:I will be running a solenoid start gate triggered via GPRM. Is that what you are suggesting?
He's suggesting a commercially available unit. However, I don't believe that it can trigger from GPRM, if that is what you are wanting to do.


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Re: What type of scheduling?

Post by *5 J's* » Tue Oct 26, 2010 11:02 am

gpraceman wrote:Not really a comparison, but at any time you can switch from times to points and vice versa to see how the standings look. While in times scoring, you can turn on/off throwing out the worst time for each racer.
Nice! Just what I would like to see.
gpraceman wrote: He's suggesting a commercially available unit. However, I don't believe that it can trigger from GPRM, if that is what you are wanting to do.
I have the circuit design and components to build an electronic start gate. I'm sure it will be similar to the ESS.



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