Composer地址：https://packagist.org/packages/werbenhu/php-number-slicing
GitHub地址：https://github.com/werbenhu/php-number-slicing
主要代码：NumberSlicing.php
思路：将数字按精度放大倍数，比如切割数字1，切割的份数是10，精度是0.01，则将1放大100 X 10倍，然后再来对加了1000倍权重后的值进行切割。切割完成之后，再将权重去除，保证总值是1。
<?php
namespace Werben\Tools;
use Exception;
class NumberSlicing {
/**
* 精确小数点，舍弃最后一位之后的数据（非四舍五入）
* floor with precision
* @param $number 要精确的数
* @param $precision 精度，比如保留到0.01，则该值为2
* @return float|int
*/
public static function floorWithPrecision($number, $precision) {
$power = pow(10, $precision);
$ret = floor($number * $power) * 1.0 / $power ;
return $ret;
}
/**
* 精确小数点，按四舍五入保留最后一位
* round with precision
* @param $number 要精确的数
* @param $precision 精度，比如保留到0.01，则该值为2
* @return float|int
*/
public static function roundWithPrecision($number, $precision) {
$power = pow(10, $precision);
$ret = round($number * $power) * 1.0 / $power ;
return $ret;
}
/**
* 将数把权重放大，比如1，要按精度0.0001分配，则先将1乘以10000然后再来分配
* random the sum weights 加上权重之后，整个要切割的数的权重总值
* @param $weight_items 用来保留，随机分配的权重值
* @param $count 要切割的份数
* @param int $each_weight 加上权重之后，每一份平均的权重值
* @param int $min_weight 加上权重之后，最小额度的值
* @return float|int
*/
public static function weightSlicing(&$weight_items, $count, $each_weight = 10, $min_weight = 3)
{
$already_count = count($weight_items);
$cur_random_full_total = ($already_count + 1) * $each_weight;
$already_random_real_total = 0;
foreach ($weight_items as $value) {
$already_random_real_total += $value;
}
$cur_random_rest = $cur_random_full_total - $already_random_real_total;
if ($already_count == $count - 1) {
$cur_random_rate = $cur_random_rest;
} else {
$cur_random_rate_max = $cur_random_rest + $each_weight - $min_weight * 2;
$cur_random_rate = $min_weight + mt_rand(0, $cur_random_rate_max);
}
$weight_items[] = $cur_random_rate;
return $cur_random_rate;
}
/**
* slicing the number
* @param int $number
* @param int $size
* @param float $precision
* @param float $min
* @return array
* @throws Exception
*/
public static function numberSlicing($number, $size, $precision = 0.01, $min = 0.01) {
if ($number * 1.0 / $size <= $min) {
throw new Exception('min number is bigger than the average value!');
}
if ($precision > 1) {
throw new Exception('precision can\'t bigger than 1!');
}
if ($min < $precision) {
throw new Exception('precision can\'t bigger than min!');
}
$weight_items = [];
$items = [];
//不加权重情况下，每一份的平均值
$each_weight = intval($number / $size);
if ($precision < 1) {
//如果精度是小数
if ($each_weight > 1) {
//如果平均值大于1，则最小额度则直接用min就可以了
//每一份的平均值乘以权重的值，比如精度为0.01，则每一份的平均值要乘以权重（100）
$each_weight = intval((1 / $precision) * $number / $size);
//最小数值也要乘以权重
$min_weight = intval(1 / $precision) * $min;
} else {
//如果平均值小于1，需要将平均值也乘以权重
$each_weight = intval(1 / $precision);
$min_weight = $each_weight * $size * $min / $number;
}
$precision_num = log10(1 / $precision);
} else {
//如果精度是整数(1)
$min_weight = $min;
$precision_num = 0;
}
$sum_item_number = 0.0;
$sum_weight = 0.0;
//先将整个数，随机按最小额度分配
for ($i = 0; $i < $size; $i++) {
$cur_weight = self::weightSlicing($weight_items, $size, $each_weight, $min_weight);
//将权重去除，换算回原先的比例
$rate = ($number * $cur_weight * 1.00) / ($size * $each_weight);
$rate = self::floorWithPrecision($rate, $precision_num);
$sum_item_number += $rate;
$sum_weight += $cur_weight;
$items[] = $rate;
}
//由于误差，随机分配后，还会遗留一些数没有完全分配完，则将剩下的数随机分配
if ($precision_num != 0) {
//如果是切割成小数
$rest = $number - $sum_item_number;
while ($rest - 0.00 > PHP_FLOAT_MIN) {
if ($rest / $min >= 1.0) {
//剩余的数大于min最小额度，则将每份最小额度随机分配
$random_index = mt_rand(0, $size - 1);
$items[$random_index] = self::roundWithPrecision($items[$random_index] + $min, $precision_num);
$sum_item_number = self::roundWithPrecision($sum_item_number + $min, $precision_num);
$rest = self::roundWithPrecision($number - $sum_item_number, $precision_num);
} else {
//剩余的数小于min最小额度，则将这最后的未分配的数随机分配
$random_index = mt_rand(0, $size - 1);
$items[$random_index] = self::roundWithPrecision($items[$random_index] + $number - $sum_item_number, $precision_num);
$sum_item_number = $number;
$rest = $number - $sum_item_number;
}
}
} else {
//如果是切割成整数
$rest = $number - $sum_item_number;
while ($rest > 0) {
if ($rest / $min >= 1) {
$random_index = mt_rand(0, $size - 1);
$items[$random_index] += $min;
$sum_item_number += $min;
$rest = $number - $sum_item_number;
} else {
$random_index = mt_rand(0, $size - 1);
$items[$random_index] += $rest;
$sum_item_number += $rest;
$rest = $number - $sum_item_number;
}
}
}
return $items;
}
}
测试代码：
use Werben\Tools\NumberSlicing;
function testIntSlicing2IntOne() {
$precision = 1; //精确度 eg: 1, 0.1, 0.01, 0.01
$size = 10; //切割的份数，the size of the number to slicing
$min = 3; //最小额度，最小额度必须大于最小精度，min amount eg: 3, 0.23, 0.05, 0.008
$number = 100; //要切割的数字，the number
$items = NumberSlicing::numberSlicing($number, $size, $precision, $min);
$sum = 0.0;
$ret_min = $number;
foreach ($items as $value) {
$sum += $value;
if ($ret_min > $value) {
$ret_min = $value;
}
}
$count = count($items);
echo "count: $count, sum: $sum, ret_min: $ret_min\n";
echo "items : ". json_encode($items) ."\n";
}
function testIntSlicing2IntTwo() {
$precision = 1; //精确度 eg: 1, 0.1, 0.01, 0.01
$size = 30; //切割的份数，the size of the number to slicing
$min = 18666; //最小额度，最小额度必须大于最小精度，min amount eg: 3, 0.23, 0.05, 0.008
$number = 800000; //要切割的数字，the number
$items = NumberSlicing::numberSlicing($number, $size, $precision, $min);
$sum = 0.0;
$ret_min = $number;
foreach ($items as $value) {
$sum += $value;
if ($ret_min > $value) {
$ret_min = $value;
}
}
$count = count($items);
echo "count: $count, sum: $sum, ret_min: $ret_min\n";
echo "items : ". json_encode($items) ."\n";
}
function testIntSlicing2FloatOne() {
$precision = 0.01; //精确度 eg: 1, 0.1, 0.01, 0.01
$size = 1000; //切割的份数，the size of the number to slicing
$min = 0.05; //最小额度，最小额度必须大于最小精度，min amount eg: 3, 0.23, 0.05, 0.008
$number = 100; //要切割的数字，the number
$items = NumberSlicing::numberSlicing($number, $size, $precision, $min);
$sum = 0.0;
$ret_min = $number;
foreach ($items as $key => $value) {
$sum += $value;
if ($ret_min > $value) {
$ret_min = $value;
}
}
$count = count($items);
echo "count: $count, sum: $sum, ret_min: $ret_min\n";
echo "items: ". json_encode($items) ."\n";
}
function testIntSlicing2FloatTwo() {
$precision = 0.00001; //精确度 eg: 1, 0.1, 0.01, 0.01
$size = 1000; //切割的份数，the size of the number to slicing
$min = 0.00005; //最小额度，最小额度必须大于最小精度，min amount eg: 3, 0.23, 0.05, 0.008
$number = 5; //要切割的数字，the number
$items = NumberSlicing::numberSlicing($number, $size, $precision, $min);
$sum = 0.0;
$ret_min = $number;
foreach ($items as $key => $value) {
$sum += $value;
if ($ret_min > $value) {
$ret_min = $value;
}
}
$count = count($items);
echo "count: $count, sum: $sum, ret_min: $ret_min\n";
echo "items: ". json_encode($items) ."\n";
}