Dbl RR, 9 Teams, 31 possible dates.

[Summit20886]

I am working on a schedule for a volleyball league that is a double round robin with 9 teams.  We have 31 potential dates to schedule the games.  I have been using using paper and pencil to try and evenly distribute the teams.  It has been a challenge as we have run into two issues: many split games (home/away) or when you solve for split games you end up with runs (6 of 7, 7 of 9) etc at home or on the road.

I would like to try and learn how to use an algorithm and computer software to do this.  I have read a few articles and published papers.  Any guidance or suggestions would be greatly helpful.

I have found a few codes that use PHP I believe, but I do not know how to utilize them:

<?php

$n = 4;           // number of players in tournament
$functions = 2;   // total number of versions of this function

if (isset($_GET['n']) && !empty($_GET['n']) && ctype_digit($_GET['n'])) {
    $n = $_GET['n'];
}
if ( $n > 40 )
    $n = 40;

$f = $functions;
if (isset($_GET['f']) && !empty($_GET['f']) && ctype_digit($_GET['f'])) {
    $f = $_GET['f'];
}
if ( $f > $functions || $f < 1 )  
    $f = $functions;

// include and run function, using values of $f and $n
include "func.generate-rr$f.php";

echo "generateRoundRobinPairings($n);<br>\\n";
echo "Version: $f<br>\\n";
echo '<pre>' . generateRoundRobinPairings($n) . '</pre>';

?>

[Ian Wakeling]

Have you tried v5.1 of my Excel generator here?

Select 9 teams in cell A1.
Click 'Home/Away' format.
Click 'Double round robin' at the far right.
Uncheck 'Multi-table layout' if you wish to see the pattern of home and away as the colours green and yellow.

If you are interested in the code that does this, the VBA function called RoundRobin in Module1 generates the basic schedule.

[wbport]

This is a schedule generator in JavaScript: rrpair.htm.

[Summit20886]

Thank you both for this help.  

Ian, I will look at the VBA function.  

Obviously, with 9 teams and the double round robin it creates 18 matches.

Is it possible to generate into 16, and show where each team would play 2 matches at one site/week?

[Ian Wakeling]

Can you clarify as I don't really understand your question.  The Excel generator will create a schedule with 18 rounds, where each team has 16 matches and two byes.

[Summit20886]

So with 9 teams and two byes, 18 rounds evenly divided gives you 9 weeks of play.

The league I am scheduling plays the contests in an 8 week period.

I wasn't sure if there was a way to program this somehow or if it's matter of pencil/paper dividing up the weeks as necessary.

[Ian Wakeling]

Unfortunately there is no provision in the Excel generator to assign dates.   I suggest you look for some league management software - this is not something I use myself, so there is nothing specific I could recommend.

[Summit20886]

Is there a way to adjust how the home/away is distributed?