Week 5 OPR

[Chris is me]

Originally Posted by sdcantrell56

1503 is an exception and not the rule. Give there robot to any other driver and it would be another decent but not great robot. Nick makes that robot excellent so saying simplicity is the secret to success is selling his skill a bit short. I stick by our teams, and the majority of successful teams decisions in that floor loading is necessary to be competitive at champs.

On the contrary, if it takes you a week less time to build a 1503 robot, you have that much longer to train your driver. You won't be Nick Lawrence, but if I could trade floor loading for a week of practice with 2791's robot, I would get rid of floor loading.

[Coach Tom]

Sorry for the simple question, but how is OPR calculated? As an example, I took the sum of 1114's Waterloo qualification round scores and divided that by the number of matches and got 80.6 -- yet their OPR for that event was 71.88. What is the algorithm? Do you count the minibot?

Others who are not familiar with this metric might benefit from knowing!

[Dr Theta]

OPR takes into account the contribution of your alliance partners, for instance our average qualification score at MN 10000 lakes was 46.333 but our OPR is actually around 22-23. It is a measure of your estimated contribution to the score.

[The Lucas]

Originally Posted by Coach Tom

Sorry for the simple question, but how is OPR calculated? As an example, I took the sum of 1114's Waterloo qualification round scores and divided that by the number of matches and got 80.6 -- yet their OPR for that event was 71.88. What is the algorithm? Do you count the minibot?

Others who are not familiar with this metric might benefit from knowing!

The simplest way to explain OPR (Offensive Power Ranking) is that it is the solution to a linear systems. The equation for each qualifying match is a sum of the OPR variable for each alliance partner equals the match score (minibots and penalties included) like this:
(OPR of Team AAAA) + (OPR of Team BBBB) + (OPR of Team CCCC) = (Match score for that Alliance)

Once you you play enough matches, and teams play with different partners (connecting a graph) you can solve this linear system for the OPR variable of each team. This is actually done in the program OPRNet using LU decomposition.

OPR seeks to find the "value" of each individual robot in a value that is similar to points but actual points. Negative OPRs occur in every event calculation, which indicates generally infective and penalty-prone robots. Average qualification score is not a good metric because it measure on how good your randomly alliances are not your individual robot. The team with the highest OPR is the "MVP of the Quals". Much like Ernie Banks, this MVP could always be on a below average randomly paired alliance (producing points when paired with low OPR partners helps your OPR).

As I said before OPRNet doesn't use Elim matches in the qualifications. You actually cant solve for OPR with just elimination matches, since alliances are always paired together (no inter pairing between robots on different alliances to make the system solvable). Also there is nothing mathematically that links different events together. Any comparison between OPRs at different events is interesting to look at, but should be taken with a grain of salt.

[Karthik]

Originally Posted by sdcantrell56

1503 is an exception and not the rule. Give there robot to any other driver and it would be another decent but not great robot. Nick makes that robot excellent so saying simplicity is the secret to success is selling his skill a bit short. I stick by our teams, and the majority of successful teams decisions in that floor loading is necessary to be competitive at champs.

As someone who has seen everyone of 1503's matches in person, let me set the record straight. Their driver has done an excellent job controlling that machine, but to give him all or even most of the credit is a disservice to that entire team and their design. I think Nick would be the first person to admit this. Remember, Nick was their driver last year, with an extremely complicated robot, and their results were less than favorable by their own standards. The reason 1503 is so successful this year is definitely the simplicity. The robot is easy and intuitive to drive, the geometry is optimized perfectly for top row scoring and the single speed drivetrain handles like a dream. I'm quite confident that if they went with a more complicated approach, they would not have been nearly as successful. A simple, well thought out robot will make any driver and team look better. Full credit to all of 1503 for recognizing this and building a robot that's dominant at smaller subset of the game, as opposed to mediocre at all facets.

[Nick Lawrence]

Originally Posted by Karthik

As someone who has seen everyone of 1503's matches in person, let me set the record straight. Their driver has done an excellent job controlling that machine, but to give him all or even most of the credit is a disservice to that entire team and their design. I think Nick would be the first person to admit this. Remember, Nick was their driver last year, with an extremely complicated robot, and their results were less than favorable by their own standards. The reason 1503 is so successful this year is definitely the simplicity. The robot is easy and intuitive to drive, the geometry is optimized perfectly for top row scoring and the single speed drivetrain handles like a dream. I'm quite confident that if they went with a more complicated approach, they would not have been nearly as successful. A simple, well thought out robot will make any driver and team look better. Full credit to all of 1503 for recognizing this and building a robot that's dominant at smaller subset of the game, as opposed to mediocre at all facets.

Thank you Karthik. You beat me to the punch here. We're not good just because I have some driver skill, but because this robot is extremely simple an maneuverable. We learned a LOT last year, and vowed to follow the principal "three things well, not five things sub-par." This started with our VRC robot. We didn't bother with hanging, we kept refining our manipulator instead. Worked out well for that robot too with two silver medals.

I hope everyone in FIRST takes notice to our robot this year. Simple works, and we have the banners to back up that philosophy.

-Nick

[Pat Fairbank]

Originally Posted by Karthik

The reason 1503 is so successful this year is definitely the simplicity.

Very true. I'd attribute the largest part of our success to the simplicity of the design allowing us to finish both robots before ship. This allowed us to fully degremlify the competition robot (a major problem for us in past years) pre-ship, and gave our programmers the time to write an autonomous mode that has yet to miss scoring an ubertube in a competition match. Plus, the simplicity of the design has necessitated a minimum of maintenance, yielding very low downtime both at competition and our practice field. From time to time, people on the team continue to ask themselves, "what if we had just added this simple mechanism to enable floor pickup?", but I'd venture to say that anything other than what we did would have resulted in less success overall.

Now, would you all please stop feeding Nick's ego? I'm the one who has to work with him (and Andrew and Jay, our awesome operator and human player) on the field, and as it stands I'm not sure his head will fit on the bus to St. Louis...