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gmp_fact

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

gmp_factFatorial

Descrição

resource gmp_fact ( int $a )

Calcula o fatorial (a!) de a.

Parâmetros

a

O número fatorial.

Ele pode ser qualquer número GMP resource, ou uma string numérica que é possível convertê-la para um número.

Valor Retornado

Um número GMP resource no PHP 5.5 e anteriores, ou um objeto GMP do PHP 5.6 em diante.

Exemplos

Exemplo #1 Exemplo gmp_fact()

<?php
$fact1 
gmp_fact(5); // 5 * 4 * 3 * 2 * 1
echo gmp_strval($fact1) . "\n";
       
$fact2 gmp_fact(50); // 50 * 49 * 48, ... etc
echo gmp_strval($fact2) . "\n";
?>

O exemplo acima irá imprimir:

120
30414093201713378043612608166064768844377641568960512000000000000

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User Contributed Notes 2 notes

up
0
raholl
2 months ago
I was expecting gmp_fact() is more effective than doing a while loop, but measurements show opposite:

<?php
$cislo
= 112;
$fact = $cislo;
$ffact = 1;
$mt = microtime();
while(
$fact >= 1)
{
   
$ffact = $fact * $ffact;
   
$fact--;
}
$md=number_format(microtime()-$mt, 6);
echo
"<h1>LOOP ($md):</h1>";
echo
$ffact;

$mt = microtime();
$vec = gmp_fact($cislo);
$md=number_format(microtime()-$mt, 6);
echo
"<h1>GMP FACT ($md):</h1>";
echo
$vec;
exit();
?>

WILL OUTPUT:

LOOP (0.000022s):
1.9745068572211E+182

GMP FACT (0.000132s):
1.9745068572211E+182

Result is 0.000022s loop, and 0.000132s gmp_fact()
up
-1
raholl
2 months ago
I was expecting gmp_fact() is more effective than doing a while loop, but measurements show opposite:

<?php
$cislo
= 112;
$fact = $cislo;
$ffact = 1;
$mt = microtime();
while(
$fact >= 1)
{
   
$ffact = $fact * $ffact;
   
$fact--;
}
$md=number_format(microtime()-$mt, 6);
echo
"<h1>LOOP ($md):</h1>";
echo
$ffact;

$mt = microtime();
$vec = gmp_fact($cislo);
$md=number_format(microtime()-$mt, 6);
echo
"<h1>GMP FACT ($md):</h1>";
echo
$vec;
exit();
?>

WILL OUTPUT:

LOOP (0.000022s):
1.9745068572211E+182

GMP FACT (0.000132s):
1.9745068572211E+182

Result is 0.000022s loop, and 0.000132s gmp_fact()
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