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#1




OPR Formula
This is going to sound extremely stupid, but what is the formula for OPR?
Thanks in advance. 
#2




Re: OPR Formula
That is not a stupid question.
OPR is actually a system of simultaneous equations. The difficulty lies in solving that many simultaneous equations. For instance. In a standard district event in Michigan, there might be 80 matches. Each match has equations that lay out like this: Robot_1_score+Robot_2_score+Robot_3_score=Red_Scor e Robot_4_score+Robot_5_score+Robot_6_score=Blue_Sco re So, in the end you'll have a system with 160 equations, and 40 variables (each robot is one variable, as shown in the equations above). The trick is solving those equations. Until just recently, excel didn't have the firepower to do it unless you used macros. However, with the newer versions, the Matrix formulas are powerful enough to do it. Keep in mind this isn't like algebra  the computer has to iterate to find an answer. This is not a simple process. It is fairly complicated. Look up "solving simultaneous equations using matrices" in excel, and you should be able to find some examples. That is how we wrote our OPR. It requires pretty indepth knowledge of excel though. You'll have to understand named arrays, matrix math functions, and array formulas. 2834 the Bionic Barons put out an awesome OPR sheet that handles the calculations through some opensource macro code. It is far more complex (to me) than using matrix formulae, because I have never used macros and vb programming in excel. Of course, programs like matlab have more advanced equation solvers and you may be able to easily write a program to perform the calculations. Last edited by Tom Line : 01292012 at 12:53 AM. Reason: Corrected team number 
#3




Re: OPR Formula
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I've done a fair amount of work with large overdetermined systems of equations (20,000 equations in 6,000 variables). I'd like to play around with some of this data. Maybe I could write and post a small app. Do you know where I could get a couple of CSV, or whitespacedelimited, or fixedfield text files from 2011? Thanks. 
#4




Re: OPR Formula
I believe you can copy and paste from the old scores on the FIRST website. For instance, here:
http://www2.usfirst.org/2011comp/eve...chresults.html That is how I developed ours. I've never tried to do the whole webscrape or download the scores automatically as they are posted by FIRST. If, however, someone could explain how that's done it would be absolutely wonderful! 
#5




Re: OPR Formula
In newer versions of Excel, go to the Data tab, and then click (under Get External Data  left most panel) "From Web". Then, you can put the URL of the results page into the little browser window that pops up and then select the table with match results. To refresh, click "Refresh All" in the Connections pane (still on the data tab).

#6




Re: OPR Formula
Also, the FIRST FMS system uploads its data in twitter posts under @frcfms so you could scrape a lot more data from that since it tells of penalties point total for instance.

#7




Re: OPR Formula
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#8




Re: OPR Formula
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Also, some fun facts I found:  there were 5,258 FRC matches played in 2011  There were 357,981 points scored total  The average individual alliance score was 34.04 points  The average total number of points per match was 68.08311145 points  The highest alliance score was 147 points 
#9




Re: OPR Formula
Many thanks for all the info. Can I assume the same basic principles hold true with DPR as well?

#10




Re: OPR Formula
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Also, I know OPR means offensive power rating, but what does this actually mean? 
#11




Re: OPR Formula
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DPR... I don't think anybody's ever come up with a good way to calculate that. First you have to find a way to calculate a defensive score... 
#12




Re: OPR Formula
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Set up the equations like so: red1+red2+red3 = blue_alliance_score ... then solve the system. The lower the number, the better the DPR. Like golf. 
#13




Re: OPR Formula
If you want to learn more about OPR, CCWM, DPR, PMR, please refer to
http://www.chiefdelphi.com/media/papers/2174 I will post an updated 2012 version of the presentation file shortly. 
#14




Re: OPR Formula
Quote:
You might be able to do it with red1+red2+red3 = blue_alliance_OPR  blue_alliance_score and the higher the score the better (due to the OPRscore) but that involves knowing the blue alliance's combined OPR. 
#15




Re: OPR Formula
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I do not agree with low DPR is a result of opposing alliance's inability to score. Over a number of matches, those teams with low OPRs will also cause other teams to experience the same thing. A team's DPR will only be higher or lower based on how they perform on average comparing to other teams. Remember OPR, DPR and CCWM are all calculations of that team's calculated contribution. 
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