# @stdlib/math-base-special-logit

0.2.2 • Public • Published

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# logit

Compute the logit function.

The logit function is defined as the logarithm of the odds `p / (1-p)`; i.e.,

The logit function is the inverse of the standard logistic function, sometimes also called the sigmoid function.

## Installation

`npm install @stdlib/math-base-special-logit`

## Usage

`var logit = require( '@stdlib/math-base-special-logit' );`

#### logit( p )

Computes the logit function.

```var v = logit( 0.2 );
// returns ~-1.386

v = logit( 0.9 );
// returns ~2.197```

If `p < 0` or `p > 1`, the function returns `NaN`.

```var v = logit( 1.3 );
// returns NaN

v = logit( -0.2 );
// returns NaN```

## Examples

```var randu = require( '@stdlib/random-base-randu' );
var logit = require( '@stdlib/math-base-special-logit' );

var p;
var i;

for ( i = 0; i < 100; i++ ) {
p = randu();
console.log( 'logit(%d) = %d', p, logit( p ) );
}```

## C APIs

### Usage

`#include "stdlib/math/base/special/logit.h"`

#### stdlib_base_logit( p )

Computes the logit function.

```double out = stdlib_base_logit( 0.2 );
// returns ~-1.386

out = stdlib_base_logit( 0.9 );
// returns ~2.197```

The function accepts the following arguments:

• p: `[in] double` input value.
`double stdlib_base_logit( const double p ); `

### Examples

```#include "stdlib/math/base/special/logit.h"
#include <stdlib.h>
#include <stdio.h>

int main( void ) {
double x;
double v;
int i;

for ( i = 0; i < 100; i++ ) {
x = (double)rand() / (double)RAND_MAX;
v = stdlib_base_logit( x );
printf( "logit(%lf) = %lf\n", x, v );
}
}```

## Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

## Package Sidebar

### Install

`npm i @stdlib/math-base-special-logit`

### Repository

github.com/stdlib-js/math-base-special-logit

stdlib.io

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