Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be discussing briefly about the php stats_rand_gen_gamma() function.
The PHP stats_rand_gen_gamma() function is used to generate a random deviate from the gamma distribution.
The PHP stats_rand_gen_gamma() function is used to generate a random deviate from the gamma distribution.
Syntax
Following below is the syntax to use this function -
float stats_rand_gen_gamma( float $a, float $r )
Parameter Details
Sr.No | Parameter | Description |
---|---|---|
1 | a | location parameter of Gamma distribution (a > 0). |
2 | r | shape parameter of Gamma distribution (r > 0). |
Return Value
This function generates a random deviate from the gamma distribution whose density is (A**R)/Gamma(R) * X**(R-1) * Exp(-A*X).
Dependencies
This built-in function was first introduced in statistics extension (PHP version 4.0.0 and PEAR v1.4.0). In this tutorial guide, we used the latest release of stats-2.0.3 (PHP v7.0.0 or newer and PEAR version 1.4.0 or newer).
Example1
Following example computes the random deviation from the gamma distribution -
<?php var_dump(is_float(stats_rand_gen_gamma(1, 1))); ?>
Output
When the above code is executed, it will produce the following result -
bool(true)
Example2
The following is an error case. In the below example, we have passed a < 0. A warning is shown in logs -
<?php // error case var_dump(stats_rand_gen_gamma(-0.1, 1)); // a < 0 ?>
Output
The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_gamma: A or R nonpositive. A value: -1.000000E-1, R value: 1.000000E+0
bool(false)
Example3
The following is an error case. In the below example, we have passed a == 0. A warning is shown in logs -
<?php // error cases var_dump(stats_rand_gen_gamma(0, 1)); // a == 0 ?>
Output
The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_gamma: A or R nonpositive. A value: 0.000000E+0, R value: 1.000000E+0
bool(false)
Example4
The following below is an error case. In the following example, we have passed r < 0. A warning is shown in logs -
<?php // error cases var_dump(stats_rand_gen_gamma(1, -.1)); // r < 0 ?>
Output
The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_gamma: A or R nonpositive. A value: 1.000000E+0, R value: -1.000000E-1
bool(false)
Example5
The following is an error case. In the below example, we have passed r == 0. A warning is shown in logs -
<?php // error cases var_dump(stats_rand_gen_gamma(1, 0)); // r == 0 ?>
Output
The above code will produce the following result and a warning in logs PHP Warning: stats_rand_gen_gamma: A or R nonpositive. A value: 1.000000E+0, R value: 0.000000E+0
bool(false)
Alright guys! This is where we are going to be rounding up for this tutorial post. In our next tutorial, we are going to be discussing about the built-in stats_rand_gen_ibinomial() Function in PHP.
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Thanks for reading and bye for now.