这篇文章是为PHP4撰写的,只需选择您的发行版:
<?php
define( 'RandomGaussian', 'gaussian' ) ;
define( 'RandomBell', 'bell' ) ;
define( 'RandomGaussianRising', 'gaussianRising' ) ;
define( 'RandomGaussianFalling', 'gaussianFalling' ) ;
define( 'RandomGamma', 'gamma' ) ;
define( 'RandomGammaQaD', 'gammaQaD' ) ;
define( 'RandomLogarithmic10', 'log10' ) ;
define( 'RandomLogarithmic', 'log' ) ;
define( 'RandomPoisson', 'poisson' ) ;
define( 'RandomDome', 'dome' ) ;
define( 'RandomSaw', 'saw' ) ;
define( 'RandomPyramid', 'pyramid' ) ;
define( 'RandomLinear', 'linear' ) ;
define( 'RandomUnweighted', 'non' ) ;
function mkseed()
{
srand(hexdec(substr(md5(microtime()), -8)) & 0x7fffffff) ;
}
function random_0_1()
{
return (float) mt_rand() / (float) mt_getrandmax() ;
}
function random_PN()
{
return (2.0 * random_0_1()) - 1.0 ;
}
function gauss()
{
static $useExists = false ;
static $useValue ;
if ($useExists) {
$useExists = false ;
return $useValue ;
} else {
$w = 2.0 ;
while (($w >= 1.0) || ($w == 0.0)) {
$x = random_PN() ;
$y = random_PN() ;
$w = ($x * $x) + ($y * $y) ;
}
$w = sqrt((-2.0 * log($w)) / $w) ;
$useValue = $y * $w ;
$useExists = true ;
return $x * $w ;
}
}
function gauss_ms( $mean,
$stddev )
{
return gauss() * ($stddev/4) + $mean;
}
function gaussianWeightedRandom( $LowValue,
$maxRand,
$mean=0.0,
$stddev=2.0 )
{
$rand_val = $LowValue + $maxRand ;
while (($rand_val < $LowValue) || ($rand_val >= ($LowValue + $maxRand))) {
$rand_val = floor(gauss_ms($mean,$stddev) * $maxRand) + $LowValue ;
$rand_val = ($rand_val + $maxRand) / 2 ;
}
return $rand_val ;
}
function bellWeightedRandom( $LowValue,
$maxRand )
{
return gaussianWeightedRandom( $LowValue, $maxRand, 0.0, 1.0 ) ;
}
function gaussianWeightedRisingRandom( $LowValue,
$maxRand )
{
$rand_val = $LowValue + $maxRand ;
while (($rand_val < $LowValue) || ($rand_val >= ($LowValue + $maxRand))) {
$rand_val = $maxRand - round((abs(gauss()) / 4) * $maxRand) + $LowValue ;
}
return $rand_val ;
}
function gaussianWeightedFallingRandom( $LowValue,
$maxRand )
{
$rand_val = $LowValue + $maxRand ;
while (($rand_val < $LowValue) || ($rand_val >= ($LowValue + $maxRand))) {
$rand_val = floor((abs(gauss()) / 4) * $maxRand) + $LowValue ;
}
return $rand_val ;
}
function logarithmic($mean=1.0, $lambda=5.0)
{
return ($mean * -log(random_0_1())) / $lambda ;
}
function logarithmicWeightedRandom( $LowValue,
$maxRand )
{
do {
$rand_val = logarithmic() ;
} while ($rand_val > 1) ;
return floor($rand_val * $maxRand) + $LowValue ;
}
function logarithmic10( $lambda=0.5 )
{
return abs(-log10(random_0_1()) / $lambda) ;
}
function logarithmic10WeightedRandom( $LowValue,
$maxRand )
{
do {
$rand_val = logarithmic10() ;
} while ($rand_val > 1) ;
return floor($rand_val * $maxRand) + $LowValue ;
}
function gamma( $lambda=3.0 )
{
$wLambda = $lambda + 1.0 ;
if ($lambda <= 8.0) {
$x = 1.0 ;
for ($j = 1; $j <= $wLambda; $j++) {
$x *= random_0_1() ;
}
$x = -log($x) ;
} else {
do {
do {
do {
$v1 = random_0_1() ;
$v2 = random_PN() ;
} while (($v1 * $v1 + $v2 * $v2) > 1.0) ;
$y = $v2 / $v1 ;
$s = sqrt(2.0 * $lambda + 1.0) ;
$x = $s * $y + $lambda ;
} while ($x <= 0.0) ;
$e = (1.0 + $y * $y) * exp($lambda * log($x / $lambda) - $s * $y) ;
} while (random_0_1() > $e) ;
}
return $x ;
}
function gammaWeightedRandom( $LowValue,
$maxRand )
{
do {
$rand_val = gamma() / 12 ;
} while ($rand_val > 1) ;
return floor($rand_val * $maxRand) + $LowValue ;
}
function QaDgammaWeightedRandom( $LowValue,
$maxRand )
{
return round((asin(random_0_1()) + (asin(random_0_1()))) * $maxRand / pi()) + $LowValue ;
}
function gammaln($in)
{
$tmp = $in + 4.5 ;
$tmp -= ($in - 0.5) * log($tmp) ;
$ser = 1.000000000190015
+ (76.18009172947146 / $in)
- (86.50532032941677 / ($in + 1.0))
+ (24.01409824083091 / ($in + 2.0))
- (1.231739572450155 / ($in + 3.0))
+ (0.1208650973866179e-2 / ($in + 4.0))
- (0.5395239384953e-5 / ($in + 5.0)) ;
return (log(2.5066282746310005 * $ser) - $tmp) ;
}
function poisson( $lambda=1.0 )
{
static $oldLambda ;
static $g, $sq, $alxm ;
if ($lambda <= 12.0) {
if ($lambda <> $oldLambda) {
$oldLambda = $lambda ;
$g = exp(-$lambda) ;
}
$x = -1 ;
$t = 1.0 ;
do {
++$x ;
$t *= random_0_1() ;
} while ($t > $g) ;
} else {
if ($lambda <> $oldLambda) {
$oldLambda = $lambda ;
$sq = sqrt(2.0 * $lambda) ;
$alxm = log($lambda) ;
$g = $lambda * $alxm - gammaln($lambda + 1.0) ;
}
do {
do {
$y = tan(pi() * random_0_1()) ;
$x = $sq * $y + $lambda ;
} while ($x < 0.0) ;
$x = floor($x) ;
$t = 0.9 * (1.0 + $y * $y) * exp($x * $alxm - gammaln($x + 1.0) - $g) ;
} while (random_0_1() > $t) ;
}
return $x ;
}
function poissonWeightedRandom( $LowValue,
$maxRand )
{
do {
$rand_val = poisson() / $maxRand ;
} while ($rand_val > 1) ;
return floor($x * $maxRand) + $LowValue ;
}
function binomial( $lambda=6.0 )
{
}
function domeWeightedRandom( $LowValue,
$maxRand )
{
return floor(sin(random_0_1() * (pi() / 2)) * $maxRand) + $LowValue ;
}
function sawWeightedRandom( $LowValue,
$maxRand )
{
return floor((atan(random_0_1()) + atan(random_0_1())) * $maxRand / (pi()/2)) + $LowValue ;
}
function pyramidWeightedRandom( $LowValue,
$maxRand )
{
return floor((random_0_1() + random_0_1()) / 2 * $maxRand) + $LowValue ;
}
function linearWeightedRandom( $LowValue,
$maxRand )
{
return floor(random_0_1() * ($maxRand)) + $LowValue ;
}
function nonWeightedRandom( $LowValue,
$maxRand )
{
return rand($LowValue,$maxRand+$LowValue-1) ;
}
function weightedRandom( $Method,
$LowValue,
$maxRand )
{
switch($Method) {
case RandomGaussian :
$rVal = gaussianWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomBell :
$rVal = bellWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomGaussianRising :
$rVal = gaussianWeightedRisingRandom( $LowValue, $maxRand ) ;
break ;
case RandomGaussianFalling :
$rVal = gaussianWeightedFallingRandom( $LowValue, $maxRand ) ;
break ;
case RandomGamma :
$rVal = gammaWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomGammaQaD :
$rVal = QaDgammaWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomLogarithmic10 :
$rVal = logarithmic10WeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomLogarithmic :
$rVal = logarithmicWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomPoisson :
$rVal = poissonWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomDome :
$rVal = domeWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomSaw :
$rVal = sawWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomPyramid :
$rVal = pyramidWeightedRandom( $LowValue, $maxRand ) ;
break ;
case RandomLinear :
$rVal = linearWeightedRandom( $LowValue, $maxRand ) ;
break ;
default :
$rVal = nonWeightedRandom( $LowValue, $maxRand ) ;
break ;
}
return $rVal;
}
?>