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I've written a small ELO class for calculating a players rating for a game league, and for the life of me I don't know why these calculations are coming up wrong.

The Class:

<?php
class elo {
function get_rating($current_rating, $expected, $win = true)
{
if ($win === true)
{
$r = $current_rating;
$add = 32;
$multiplier = 1 - $expected;
$add = $add*$multiplier;
$r = $current_rating + $add;
return round($r,0);
}
else
{
$r = $current_rating;
$add = 32;
$multiplier = 0 - $expected;
$add = $add*$multiplier;
$r = $current_rating + $add;
return round($r,0);
}
}

function get_expected($player1_rating, $player2_rating)
{
$e = 1;
$divider = 1;
$power_of = $player2_rating - $player1_rating;
$power_of = $power_of / 400;
$power_of = 10^($power_of);
$divider = $divider + $power_of;
$e = $e/$divider;
return round($e,2);
}
}

Code for testing:

$elo = new elo();
$a = 1000;
$b = 1000;
$chance['a'] = $elo->get_expected($a,$b);
$chance['b'] = $elo->get_expected($b,$a);
$chance['%a'] = $chance['a'] * 100;
$chance['%b'] = $chance['b'] * 100;
echo "Player A ({$a}) has a " . $chance['%a'] . "% Chance of winning.<br/>"; //should be 50% (0.5)
echo "Player B ({$b}) has a " . $chance['%b'] . "% chance of winning.<br/>"; //should be 50% (0.5)
$winpoints['a'] = $elo->get_rating($a, $chance['a']); //should return 1016
$winpoints['b'] = $elo->get_rating($b, $chance['b']); //should return 1016
echo "Player A's new rating will be {$winpoints['a']} if they win.<br/>";
echo "Player B's new rating will be {$winpoints['b']} if they win.<br/>";
$losspoints['a'] = $elo->get_rating($a, $chance['a'], false); //should return 984
$losspoints['b'] = $elo->get_rating($b, $chance['b'], false); //should return 984
echo "Player A's new rating will be {$losspoints['a']} if they lose.<br/>";
echo "Player B's new rating will be {$losspoints['b']} if they lose.<br/>";

The output i'm getting is as follows, when they should match what i've stated above (as done on paper with a calculator)

Player A (1000) has a 9% Chance of winning.
Player B (1000) has a 9% chance of winning.
Player A's new rating will be 1029 if they win.
Player B's new rating will be 1029 if they win.
Player A's new rating will be 997 if they lose.
Player B's new rating will be 997 if they lose.
I've tried re-writing the calculation over and over but just can't get it. I used the Wikipedia page to get my calculations. I've not added K Factor yet but I will be at some point.

Hello, I am trying to take the calculations of two variables to create a new data for a new variable. For example.....   LRH_calcLevel($LRH_current, $LRH_bankfull); +/- $LRH_totalDepth = $newVar    Which should translate to -10.43 Ft +/- 40 = $newVar (-29.57) <----- What I want   Instead it is showing up as 10.43 Ft +/- 40 = $newVar (-50.43) <----- How it is displaying which is incorrect   Here is the code I am using. The second function is what I am trying to use to create the new variable data based on the calculations above from the data provide via XML. How can I get this to display correctly?   -Thanks

//Parse Lake Ray Hubbard XML Data
$site = simplexml_load_file($LRH_data);{

        $LRH_bankfull   = '435.5';
        $LRH_totalDepth = '40';
        $LRH_current    = $site->observed->datum[0]->primary;
        $LRH_vaild      = $site->observed->datum[0]->valid;
        $LRH_updated    = DATE("D, M d, g:i a", STRTOTIME($LRH_vaild));

}

//Lets calculate the lake depatures from full pool for Lake Ray Hubbard
function LRH_calcLevel($LRH_current, $LRH_bankfull)
{
    //Get float values from strings
    $LRH_current = floatval($LRH_current);
    $LRH_bankfull = floatval($LRH_bankfull);
    //Calculate the difference
    $LRH_calcLevel = $LRH_current - $LRH_bankfull;
    //Format difference to two decimal places and add 'Ft'
    $LRH_calcLevelStr = (string) number_format($LRH_calcLevel, 2) . ' Ft';
    //If vlaue is positive add a + to beginning
    if($LRH_calcLevel>0) { $LRH_calcLevelStr = '+'.$LRH_calcLevelStr; }
    //Return the calculated formatted value
    return $LRH_calcLevelStr;
}

////Lets calculate the lake percentage from full pool for Lake Ray Hubbard
$val1 = $LRH_current;
$val2 = $LRH_bankfull;

$LRH_prec = ( $val1 / $val2) * 100;

// 1 digit after the decimal point
$LRH_prec = round($LRH_prec, 1);

//Lets convert the depature from full pool for Lake Ray Hubbard
function LRH_calcDepth($LRH_calcLevelStr, $LRH_totalDepth)
{
    //Get float values from strings
    $LRH_calcDepthStr = floatval($LRH_calcLevelStr);
    $LRH_totalDepth = floatval($LRH_totalDepth);
    //Calculate the difference
    $LRH_calcDepth = $LRH_calcDepthStr - $LRH_totalDepth;
    //Format difference to two decimal places and add 'Ft'
    $LRH_calcDepthStr = (string) number_format($LRH_calcDepth, 2) . ' Ft';
    //If vlaue is positive add a + to beginning
    if($LRH_calcDepth>0) { $LRH_calcDepthStr = '+'.$LRH_calcDepthStr; }
    //Return the calculated formatted value
    return $LRH_calcDepthStr;
}

////Lets calculate the lake percentage from full pool for Lake Ray Hubbard
$val1 = LRH_calcLevel($LRH_current, $LRH_bankfull);
$val2 = $LRH_totalDepth;

Hi,

I have been set a task to use 300000 values from a csv to find the total amount of the values and the averages of the values (mode, mean and median).

The csv is set into 2 columns, number and amount with 300000 records for each. I am unsure as to how to use only the values from one of the columns in order to get the results i need. Below is the code I have so far;

Code: [Select]
$filepath = "testdata.csv";
$file = fopen($filepath, "r") or die("Error opening file");
$i = 0;

while(($line = fgetcsv($file)) !== FALSE) {
    if($i == 0) {
        $c = 0;
        foreach($line as $col) {
            $cols[$c] = $col;
            $c++;
        }
    } else if($i > 0) {
        $c = 0;
        foreach($line as $col) {
            $data[$i][$cols[$c]] = $col;
            $c++;
        }
    }
    $i++;
}

//this prints the whole of the data still
while (($cols[1])) print_r($data);

//this still prints all the data!!
while ($data) print_r($cols[1].$data);
Am I going about this wrong by using an associative array?

Hi guys, I'm working on a project and I can't wrap my head around on a calculation that needs to be done on a multidimensional array. Quick background, it's a hotel benchmarking tool and I need to calculate the market penetration index (MPI). I have an array with 3 main arrays. First 2 are the hotels which are being compared and the last one is the MPI array.

Each array contains an array  for every month the user selects. Inside THAT array is data that needs to be used for calculations.
Here is an example:
Code: [Select]
Array
(
    [Competitive set] => Array
        (
            [Sep 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-09-01
                            [maxmonth] => 2011-09-01
                            [nrcheck] => 13
                            [data] => 67.6
                        )

                )

            [Oct 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-10-01
                            [maxmonth] => 2011-10-01
                            [nrcheck] => 13
                            [data] => 63.6
                        )

                )

            [Nov 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-11-01
                            [maxmonth] => 2011-11-01
                            [nrcheck] => 13
                            [data] => 59.2
                        )

                )

            [Dec 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-12-01
                            [maxmonth] => 2011-12-01
                            [nrcheck] => 13
                            [data] => 54.6
                        )

                )

        )

    [Test] => Array
        (
            [Sep 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-09-01
                            [maxmonth] => 2011-09-01
                            [nrcheck] => 89
                            [data] => 71.5
                        )

                )

            [Oct 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-10-01
                            [maxmonth] => 2011-10-01
                            [nrcheck] => 89
                            [data] => 67.0
                        )

                )

            [Nov 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-11-01
                            [maxmonth] => 2011-11-01
                            [nrcheck] => 91
                            [data] => 63.1
                        )

                )

            [Dec 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-12-01
                            [maxmonth] => 2011-12-01
                            [nrcheck] => 89
                            [data] => 57.5
                        )

                )

        )

    [MPI] => Array
        (
            [Sep 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-09-01
                            [maxmonth] => 2011-09-01
                            [nrcheck] => 89
                            [data] => 71.5
                        )

                )

            [Oct 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-10-01
                            [maxmonth] => 2011-10-01
                            [nrcheck] => 89
                            [data] => 67.0
                        )

                )

            [Nov 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-11-01
                            [maxmonth] => 2011-11-01
                            [nrcheck] => 91
                            [data] => 63.1
                        )

                )

            [Dec 11] => Array
                (
                    [0] => Array
                        (
                            [minmonth] => 2011-12-01
                            [maxmonth] => 2011-12-01
                            [nrcheck] => 89
                            [data] => 57.5
                        )

                )

        )

)
Currently the  'data' for MPI is wrong. That needs to become the data of the first array divided by the data of the second array and multiplied by 100 (percentage).

How would I go about doing that? The foreach loops are a bit too big for me on this one.

Hi

I was wondering if somebody could give me some help.

I have a form with the following table for users to input 

			<td width="118" style="text-align: left"><input type="text" name="item1cost"></td>
	        <td width="118" style="text-align: left"><input type="text" name="item1Charge"></td>
			<td width="118" style="text-align: left"><input type="text" name="item1sum""></td>

is there a way to have the 3rd field auto populated by calculations made from the data a user puts in the 1st and 2nd field ?

The calculation i am actually looking for i can explain easier in excel terms

Lets say 

item1cost is in A2

Item1charge is in B2

Item1sum is in C3

A3 would be the cell i want populating with the calculation of 
=SUM(B2-(A2*1.295))

any help would be greatly appreciated

thanks

 

//
I am trying to calculate the number of days between dates and have a major problem.  When I try the example below, it gives me exactly 201 days, yet the dates have different times, meaning that a full day is impossible.  If it matters, I am testing via xampp 1.7.3 with php version 5.3.1 with Windows XP.  Can anyone explain what I am doing wrong.  Can daylight savings play a role?

        $frmritedate7116    =    strtotime('2010-12-13 23:00');
        $frmritedate7156    =    strtotime('2010-05-27 00:00');
//
        $frmritedate7251    =    $frmritedate7156 - $frmritedate7116;
//
//
1274943600-1292310000=-17366400 // 86400 seconds in a day ( 201.00 )
//
//
//