BCMath 任意精度数学
- 简介
- 安装/配置
- BC 数学 函数
- bcadd — 两个任意精度数字的加法计算
- bcceil — Round up arbitrary precision number
- bccomp — 比较两个任意精度的数字
- bcdiv — 两个任意精度的数字除法计算
- bcdivmod — Get the quotient and modulus of an arbitrary precision number
- bcfloor — Round down arbitrary precision number
- bcmod — 任意精度数字取模
- bcmul — 两个任意精度数字乘法计算
- bcpow — 任意精度数字的乘方
- bcpowmod — Raise an arbitrary precision number to another, reduced by a specified modulus
- bcround — Round arbitrary precision number
- bcscale — 设置/获取所有 bc math 函数的默认小数点保留位数
- bcsqrt — 任意精度数字的二次方根
- bcsub — 两个任意精度数字的减法
- BcMath\Number — The BcMath\Number class
- BcMath\Number::add — Adds an arbitrary precision number
- BcMath\Number::ceil — Rounds up an arbitrary precision number
- BcMath\Number::compare — Compares two arbitrary precision numbers
- BcMath\Number::__construct — Creates a BcMath\Number object
- BcMath\Number::div — Divides by an arbitrary precision number
- BcMath\Number::divmod — Gets the quotient and modulus of an arbitrary precision number
- BcMath\Number::floor — Rounds down an arbitrary precision number
- BcMath\Number::mod — Gets the modulus of an arbitrary precision number
- BcMath\Number::mul — Multiplies an arbitrary precision number
- BcMath\Number::pow — Raises an arbitrary precision number
- BcMath\Number::powmod — Raises an arbitrary precision number, reduced by a specified modulus
- BcMath\Number::round — Rounds an arbitrary precision number
- BcMath\Number::__serialize — Serializes a BcMath\Number object
- BcMath\Number::sqrt — Gets the square root of an arbitrary precision number
- BcMath\Number::sub — Subtracts an arbitrary precision number
- BcMath\Number::__toString — Converts BcMath\Number to string
- BcMath\Number::__unserialize — Deserializes a data parameter into a BcMath\Number object
＋添加备注
用户贡献的备注 3 notes
Hayley Watson ¶
9 years ago
This extension is an interface to the GNU implementation as a library of the Basic Calculator utility by Philip Nelson; hence the name.
volek at adamv dot cz ¶
10 years ago
Note that when you use implementation of factorial that ClaudiuS made, you get results even if you try to calculate factorial of number that you normally can't, e.g. 2.5, -2, etc. Here is safer implementation:
<?php
/**
* Calculates a factorial of given number.
* @param string|int $num
* @throws InvalidArgumentException
* @return string
*/
function bcfact($num)
{
if (!filter_var($num, FILTER_VALIDATE_INT) || $num <= 0) {
throw new InvalidArgumentException(sprintf('Argument must be natural number, "%s" given.', $num));
}
for ($result = '1'; $num > 0; $num--) {
$result = bcmul($result, $num);
}
return $result;
}
?>
ClaudiuS ¶
12 years ago
Needed to compute some permutations and found the BC extension great but poor on functions, so untill this gets implemented here's the factorial function:
<?php
/* BC FACTORIAL
* n! = n * (n-1) * (n-2) .. 1 [eg. 5! = 5 * 4 * 3 * 2 * 1 = 120]
*/
function bcfact($n){
$factorial=$n;
while (--$n>1) $factorial=bcmul($factorial,$n);
return $factorial;
}
print bcfact(50);
//30414093201713378043612608166064768844377641568960512000000000000
?>