Because I need to use php to generate 0~1 random decimals for my work, I wrote an article before "php method to generate 0~1 random decimals", based on mt_rand() and mt_getrandmax()accomplish.

Later some netizens commented that the PHP native method lcg_value() can generate random decimals from 0 to 1.

lcg_value Description

float lcg_value ( void )

lcg_value() returns a pseudo-random number in the range (0, 1). This function combines two congruential generators with periods 2^31 - 85 and 2^31 - 249. The period of this function is equal to the product of these two prime numbers.

Return: pseudo-random number in the range (0, 1).

Output:

0.11516515851995
0.064684551575297
0.68275174031189
0.55730746529099
0.70215008878091

Comparison of two methods of generating random decimals from 0 to 1

1. Execution time comparison

The running time of executing 100,000 times based on mt_rand() and mt_getrandmax() algorithms

Output: run time 266.893148 ms

Running time of executing lcg_value() 100,000 times

Output: run time 86.178064 ms

Execution time comparison, because lcg_value() is directly a native PHP method, and mt_rand() and mt_getrandmax() need to call two methods and need to be calculated, so The execution time of lcg_value() is about 3 times faster.

2. Random effect comparison

Random effect based on mt_rand() and mt_getrandmax() algorithms

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        }else{
            imagesetpixel($im, $x, $y, $color2);
        }
    }
}
imagepng($im);
imagedestroy($im);?>

Random effect diagram:

##Random effect of lcg_value()

=0.5){
            imagesetpixel($im, $x, $y, $color1);
        }else{
            imagesetpixel($im, $x, $y, $color2);
        }
    }
}
imagepng($im);
imagedestroy($im);?>

Comparing the random effects, it can be seen that using mt_rand() and mt_getrandmax( ) algorithm generates random effects that are out of order, and the random effects are better than lcg_value().
This article explains the comparison of the effects of generating 0~1 random decimals between php lcg_value and mt_rand. For more related content, please pay attention to the php Chinese website.

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