README.md

Mode

Poisson distribution mode.

The mode for a Poisson random variable is

$$\mathop{\mathrm{mode}}\left( X \right) = \lfloor \lambda \rfloor$$

where λ is the mean parameter.

Usage

var mode = require( '@stdlib/stats/base/dists/poisson/mode' );

mode( lambda )

Returns the mode of a Poisson distribution with mean parameter lambda.

var v = mode( 9.0 );
// returns 9

v = mode( 0.5 );
// returns 0

If provided lambda < 0, the function returns NaN.

var v = mode( -1.0 );
// returns NaN

Examples

var uniform = require( '@stdlib/random/array/uniform' );
var logEachMap = require( '@stdlib/console/log-each-map' );
var mode = require( '@stdlib/stats/base/dists/poisson/mode' );

var opts = {
    'dtype': 'float64'
};
var lambda = uniform( 10, 0.0, 20.0, opts );

logEachMap( 'λ: %0.4f, mode(X;λ): %0.4f', lambda, mode );

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C APIs

Usage

#include "stdlib/stats/base/dists/poisson/mode.h"

stdlib_base_dists_poisson_mode( lambda )

Returns the mode of a Poisson distribution.

double out = sstdlib_base_dists_poisson_mode( 9.0 );
// returns 9

The function accepts the following arguments:

• lambda: [in] double mean parameter.

double stdlib_base_dists_poisson_mode( const double lambda );

Examples

#include "stdlib/stats/base/dists/poisson/mode.h"
#include <stdlib.h>
#include <stdio.h>

static double random_uniform( const double min, const double max ) {
    double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
    return min + ( v*(max-min) );
}

int main( void ) {
    double lambda;
    double y;
    int i;

    for ( i = 0; i < 10; i++ ) {
        lambda = random_uniform( 0.0, 10.0 );
        y = stdlib_base_dists_poisson_mode( lambda );
        printf( "λ: %.4f, Mode(X;λ): %.4f\n", lambda, y );
    }
}