Re: OPR
 

It's important to note that in your (excellent) discussion above, [A] is a non-square binary matrix (each element is either 1 or 0) with 2M rows and T columns, where M is the number of matches and T is the number of teams... and [b] is a 2M by 1 column vector of alliance scores. So [A][x]≈[b] is indeed an overdetermined system which has no exact solution.

But if you look carefully at the way saikiranra defined the matrix [A] and the column vector [b], you'll see that his [A] is actually [N]=[A^T][A] and his [b] is actually [d]=[A^T][b].

[N] will be a square symmetric positive definite matrix, and [N][x]=[d] will have an exact solution because it's already in the Normalized Equations form. The exact solution to [N][x]=[d] will be the least-squares approximate solution to [A][x]≈[b] (to within computer floating-point rounding error).

It is also important to note that least squares is not the only criterion for minimizing the residual vector ε=[A][x]-[b]. For example, you could choose to minimize the L1 norm of ε (least absolute deviation) instead of minimizing the L2 norm (least squares).

That is conceptually true, but it is far faster (computationally) to form the system [N][x]=[d] and solve it that way.

Re: OPR
 

Can anyone show me how to use the thebluealliance.com API to get ranking, match and alliance selection data? I am not able to get it from the FIRST website. I am hoping I don't have to do manual copy and paste. I would like to call it from VBA in my Excel scouting database. Is that possible?

Re: OPR
 

Not an Excel wizard, but I can help with the TBA API. You can find the documentation here.

Keep in mind all requested need a 'X-TBA-App-Id' header (or GET URL parameter, see below), it'll look like: '<team/person id>:<app description>:<version> '

Here are the endpoints you'll need (you can play around with test requests on the apidocs page)

Rankings: /api/v2/event/<key>/rankings
Results: /api/v2/event/<key>/matches
Alliances: /api/v2/event/<key> [alliances will be a field in this response]


You can also get the calculated OPR/DPR/CCWM stats at /api/v2/event/<key>/stats

And here are a couple StackOverflow threads that may or may not be helpful fetching/parsing JSON data:
https://stackoverflow.com/questions/...-unknown-proxy
https://stackoverflow.com/questions/...rnal-libraries

Re: OPR
 

Can you give a full example using the "/api/v2/event/<key>/matches" endpoint?

Can this just be typed into the URL bar of a browser?

Can it be typed at a Windows or Linux command line, and have the output redirected to a file?

Re: OPR
 

The API works with all HTTP GET requests, so you can enter it in a browser, provided you provide a GET paramter 'X-TBA-App-Id' with your ID. Otherwise, it'll just throw an error (like this). Here is an example of a properly formed URL.

I keep the following bash alias on my computer that I use for test calls
That way, I can run things like this:

Re: OPR
 

Actually, the X-TBA-App-Id can be set as a URL param. Example: http://www.thebluealliance.com/api/v...ugene:test:v01

Edit: Phil ninjaed my ninja.

Re: OPR
 

I just noticed that URL retrieves 2014 data.

I replaced "2014necmp" with "2015inind" and examined the resulting data... and the "score breakdown" doesn't appear to include coopertition, tote, or container. Am I doing something wrong, or is the shiny new 2015 FRC API not providing that data?

Re: OPR
 

It's not in the API https://usfirst.collab.net/sf/go/artf4008

Re: OPR
 

Thanks Joe for that authoritative and definitive link.

So no Twitter data for 2015, and no per-match scoring categories in the API. Very un-inspiring for the stats mavens :-(

I am presently listening to the WMV audio recording to try to understand how such a decision was arrived at.

Re: OPR
 

Any thoughts this year on "Modified" OPR? Looking at competition scores, I am a bit inclined to divide the Co-Op portion of the points in half. I would put this similar to 2012 whee you had to add points for the Co-Op bridge. In this scenario, both alliances have to bring some Co-Op to the middle in order to get the points.

I can definitely see where component OPR (RCs, Co-Ops, Totes,...) would be powerful this year if you do not have scouting.

Re: OPR
 

Please someone make an easy to use (at event) component OPR calc :rolleyes:

I'll pay with 973 swag if someone does.

Re: OPR
 

I'd totally do this if I didn't have to go to class in an hour and wasn't volunteering this weekend.

Heck, I'll probably do it anyways.

Re: OPR
 

I'm fine if you finish by next wednesday ;)

Re: OPR
 

I'm really interested in that DPR this year...;)

Re: OPR
 

By my calculations, DPR this year is 83% fear factor and 17% taking-cans-in-auto*

*Results not scientific