function simple_sort ($array
{
sort$array);
return $array
}
Author: ToneDJCampbell
eXorithm – Execute Algorithm: History For Algorithm check_domain
check_domain    version 0.1    Check a domain name against a whitelist and blacklist.
Unique Image
<?php
/**
* unique_image
*
* Generate a pseudo-unique "hash" image based on a string.
*
* @version 0.3
* @author Contributors at eXorithm
* @link /algorithm/view/unique_image Listing at eXorithm
* @link /algorithm/history/unique_image History at eXorithm
* @license /home/show/license
*
* @param mixed $string
* @return resource GD image
*/
function unique_image($string='whatever')
{
$size=200;
$steps=5;
$step=$size/$steps;
$image = image_create_alpha($size, $size);
$n = 0;
$prev = 0;
$len = strlen($string);
$sum = 0;
for ($i=0;$i<$len;$i++) $sum += ord($string[$i]);
for ($i=0;$i<$steps;$i++) {
for ($j=0;$j<$steps;$j++) {
$letter = $string[$n++ % $len];
$u = ($n % (ord($letter)+$sum)) + ($prev % (ord($letter)+$len)) + (($sum-1) % ord($letter));
$color = imagecolorallocate($image, pow($u*$prev+$u+$prev+5,2)%256, pow($u*$prev+$u+$prev+3,2)%256, pow($u*$prev+$u+$prev+1,2)%256);
if (($u%2)==0)
imagefilledpolygon($image, array($i*$step, $j*$step, $i*$step+$step, $j*$step, $i*$step, $j*$step+$step), 3, $color);
$prev = $u;
$u = ($n % (ord($letter)+$len)) + ($prev % (ord($letter)+$sum)) + (($sum-1) % ord($letter));
if (($u%2)==0)
imagefilledpolygon($image, array($i*$step, $j*$step+$step, $i*$step+$step, $j*$step+$step, $i*$step+$step, $j*$step), 3, $color);
$prev = $u;
}
}
return $image;
}
/**
* image_create_alpha
*
* Helper function to create a new blank image with transparency.
*
* @version 0.1
* @author Contributors at eXorithm
* @link /algorithm/view/image_create_alpha Listing at eXorithm
* @link /algorithm/history/image_create_alpha History at eXorithm
* @license /home/show/license
*
* @param mixed $width
* @param mixed $height
* @return resource GD image
*/
function image_create_alpha($width='',$height='')
{
// Create a normal image and apply required settings
$img = imagecreatetruecolor($width, $height);
imagealphablending($img, false);
imagesavealpha($img, true);
// Apply the transparent background
$trans = imagecolorallocatealpha($img, 0, 0, 0, 127);
for ($x = 0; $x < $width; $x++)
{
for ($y = 0; $y < $height; $y++)
{
imagesetpixel($img, $x, $y, $trans);
}
}
return $img;
}
?>
Simple Sort
<?php
/**
* simple_sort
*
* Sort an array and display it.
*
* @version 0.1
* @author Contributors at eXorithm
* @link /algorithm/view/simple_sort Listing at eXorithm
* @link /algorithm/history/simple_sort History at eXorithm
* @license /home/show/license
*
* @param array $array
* @return array
*/
function simple_sort($array=array(0=>'1',1=>'11',2=>'22',3=>'3',4=>'4'))
{
sort($array);
return $array;
}
?>
eXorithm – Execute Algorithm: View / Run Algorithm convert2grayscale
function convert2grayscale ($image
{
$height = imagesy$image);
$width = imagesx$image);
$tc = imageistruecolor$image);
$new_image = imagecreatetruecolor$width, $height);
imagealphablending$new_image, false);
imagesavealpha$new_image, true);
for ($ii=0; $ii$width; $ii++) {
for ($jj=0; $jj$height; $jj++) {
$rgb = imagecolorat$image, $ii, $jj);
if ($tc) {
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
$alpha = ($rgb >> 24) & 0xFF;
} else {
$rgb = imagecolorsforindex$image, $rgb);
$r = $rgb'red'];
$g = $rgb'green'];
$b = $rgb'blue'];
$alpha = $rgb'alpha'];
}
$avg = round(($r$g$b)/3);
$color = imagecolorallocatealpha$new_image, $avg, $avg, $avg, $alpha);
imagesetpixel$new_image, $ii, $jj, $color);
}
}
return $new_image
}
eXorithm – Execute Algorithm: Highest Rated Algorithms
eXorithm – Execute Algorithm: Algorithms Beginning with K
PI Digits
<?php
/**
* pi_digits
*
* Calculate the digits of pi.
*
* @version 0.4
* @author Contributors at eXorithm
* @link /algorithm/view/pi_digits Listing at eXorithm
* @link /algorithm/history/pi_digits History at eXorithm
* @license /home/show/license
*
* @param number $digits
* @return mixed
*/
function pi_digits($digits=500)
{
$n = floor($digits * 14/4);
$scale = 10000;
$init = 2000;
$carry = 0;
$result = '';
for($i=0;$i<=$n;$i++) {
$arr[$i] = $init;
}
for($i=$n;$i>0;$i=$i-14) {
$sum = 0;
for($j=$i;$j>0;$j--) {
$sum = ($sum * $j) + ($scale * $arr[$j]);
$arr[$j] = $sum % (($j*2)-1);
$sum = floor($sum / (($j*2)-1));
}
$result .= sprintf("%04d", ($carry + ($sum / $scale)));
$carry = $sum % $scale;
}
if ($digits>1) {
return $result[0].'.'.substr($result,1,$digits-1);
} else {
return substr($result,0,$digits);
}
}
?>
eXorithm – Execute Algorithm: View / Run Algorithm rot13
function rot13 ($string
{
for$i=0;$istrlen$string);$i++) {
$jord$string$i]);
if ((($j>=ord"n")) & ($j<=ord"z"))) | ($j>=ord"N")) & ($j<=ord"Z"))) {
$j$j-13;
}
elseif ((($j>=ord"a")) & ($j<=ord"m"))) | ($j>=ord"A")) & ($j<=ord"M"))) {
$j$j+13;
}
$new.=chr$j);
}
return$new);
}
eXorithm – Execute Algorithm: View / Run Algorithm draw_sierpinski
function draw_sierpinski ($size, $color
{
// see http://en.wikipedia.org/wiki/Sierpinski_triangle
// this code from http://php.net/manual/en/function.imagesetpixel.php
$hght = roundsqrt$size$size - ($size/2)*($size/2)));
$diff = round(($size - $hght)/2);
$gd = imagecreatetruecolor$size, $size);
$corners[0] = array'x' => round$size/2), 'y' => $diff);
$corners[1] = array'x' => 0, 'y' => $size$diff);
$corners[2] = array'x' => $size, 'y' => $size$diff);
$red = hexdecsubstr$color, 0, 2));
$green = hexdecsubstr$color, 2, 2));
$blue = hexdecsubstr$color, 4, 2));
$color = imagecolorallocate$gd, $red, $green, $blue);
$x = $size
$y = $size
for ($i = 0; $i < 200000; $i++) {
imagesetpixel$gd, round$x),round$y), $color);
$a = rand(0, 2);
$x = ($x + $corners$a]['x']) / 2;
$y = ($y + $corners$a]['y']) / 2;
}
return $gd
}