/usr/share/nickle/examples/qbrating.5c is in nickle 2.81-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 | /*
* Official NFL QB rating
*
* Copyright © 1999, 2006 Bart Massey.
* All Rights Reserved. See the file COPYING in this directory
* for licensing information.
*
* Info from
* http://www.nfl.com/news/981202qbrate.html
* http://www.bluedonut.com/qbrating.htm
* As per reference 1, you should get
* qbrating(461,324,3969,35,10) ~= 112.79
* for Steve Young. Reference 2 refers to the
* formula as a "quadratic" equation; it's actually
* a linear equation in the averages, hence the
* Nickle exact rational implementation.
*/
/*
* The "QB Rating" is only a rating of passing
* effectiveness, and it's pretty marginal at that. See the
* references above for details. The basic rationale is
* that there are four categories considered: completions,
* passing yards, passing touchdowns, and interceptions.
* For each category, the interesting statistic is the
* average over the number of passing attempts.
*
* The category scores are first scaled such that a score of
* 1 is roughly average. The scaling is then tweaked to
* attempt to make a score of 0 awful and of 2 exceptional.
* A maximum of 2.375 and minimum of 0 seem mostly to be a
* guard against anomalies. The sum of the categorie scores
* is the QB score.
*
* The QB score is then scaled such that a score of 1
* (average) in each category gives a scaled score of
* 66.{6}%. This is the QB rating. A rating of 100 is
* considered quite good.
*/
rational qbrating (int attempts, int completions, int yards,
int touchdowns, int interceptions)
{
rational cat_max = 2.375;
rational cat_score(rational base, rational offset,
rational scale) {
rational avg = base / attempts;
rational score = (avg * 100 + offset) * scale;
if (score < 0)
return 0;
if (score > cat_max)
return cat_max;
return score;
}
rational total = cat_score(completions, -30, 0.05);
total += cat_score(yards, -300, 0.0025);
total += cat_score(touchdowns, 0, 0.2);
total += cat_max - cat_score(interceptions, 0, 0.25);
return total * 100 / 6;
}
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