# invf
> Compute the [multiplicative inverse][multiplicative-inverse] of a single-precision floating-point number.
The [multiplicative inverse][multiplicative-inverse] (or **reciprocal**) is defined as
## Usage
```javascript
var invf = require( '@stdlib/math/base/special/invf' );
```
#### invf( x )
Computes the [multiplicative inverse][multiplicative-inverse] of a single-precision floating-point number `x`.
```javascript
var v = invf( -1.0 );
// returns -1.0
v = invf( 2.0 );
// returns 0.5
v = invf( 0.0 );
// returns Infinity
v = invf( -0.0 );
// returns -Infinity
v = invf( NaN );
// returns NaN
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var invf = require( '@stdlib/math/base/special/invf' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu()*100.0 ) - 50.0;
console.log( 'invf(%d) = %d', x, invf( x ) );
}
```
* * *
## C APIs
### Usage
```c
#include "stdlib/math/base/special/invf.h"
```
#### stdlib_base_invf( x )
Computes the multiplicative inverse of a single-precision floating-point number.
```c
float y = stdlib_base_invf( 2.0f );
// returns 0.5f
```
The function accepts the following arguments:
- **x**: `[in] float` input value.
```c
float stdlib_base_inv( const float x );
```
### Examples
```c
#include "stdlib/math/base/special/invf.h"
#include
int main() {
float x[] = { 3.0f, 4.0f, 5.0f, 12.0f };
float y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_invf( x[ i ] );
printf( "inv(%f) = %f\n", x[ i ], y );
}
}
```
[multiplicative-inverse]: https://en.wikipedia.org/wiki/Multiplicative_inverse
