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
?>
BCMath Arbitrary Precision Mathematics
- Introduction
- Installing/Configuring
- Predefined Constants
- BC Math Functions
- bcadd — Add two arbitrary precision numbers
- bccomp — Compare two arbitrary precision numbers
- bcdiv — Divide two arbitrary precision numbers
- bcmod — Get modulus of an arbitrary precision number
- bcmul — Multiply two arbitrary precision number
- bcpow — Raise an arbitrary precision number to another
- bcpowmod — Raise an arbitrary precision number to another, reduced by a specified modulus
- bcscale — Set default scale parameter for all bc math functions
- bcsqrt — Get the square root of an arbitrary precision number
- bcsub — Subtract one arbitrary precision number from another
ClaudiuS ¶
4 months ago
