# normalize
> Return a normal number `y` and exponent `exp` satisfying `x = y * 2^exp`.
## Usage
```javascript
var normalize = require( '@stdlib/number/float64/base/normalize' );
```
#### normalize( x )
Returns a normal number `y` and exponent `exp` satisfying `x = y * 2^exp`.
```javascript
var pow = require( '@stdlib/math/base/special/pow' );
var out = normalize( 3.14e-319 );
// returns [ 1.4141234400356668e-303, -52 ]
var y = out[ 0 ];
var exp = out[ 1 ];
var bool = ( y*pow(2.0, exp) === 3.14e-319 );
// returns true
```
The function expects a finite, non-zero numeric value `x`. If `x == 0`,
```javascript
var out = normalize( 0.0 );
// returns [ 0.0, 0 ];
```
If `x` is either positive or negative `infinity` or `NaN`,
```javascript
var PINF = require( '@stdlib/constants/float64/pinf' );
var NINF = require( '@stdlib/constants/float64/ninf' );
var out = normalize( PINF );
// returns [ Infinity, 0 ]
out = normalize( NINF );
// returns [ -Infinity, 0 ]
out = normalize( NaN );
// returns [ NaN, 0 ]
```
#### normalize.assign( x, out, stride, offset )
Returns a normal number `y` and exponent `exp` satisfying `x = y * 2^exp` and assigns results to a provided output array.
```javascript
var Float64Array = require( '@stdlib/array/float64' );
var out = new Float64Array( 2 );
var v = normalize.assign( 3.14e-319, out, 1, 0);
// returns [ 1.4141234400356668e-303, -52 ]
var bool = ( v === out );
// returns true
```
## Examples
```javascript
var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
var randu = require( '@stdlib/random/base/uniform' );
var pow = require( '@stdlib/math/base/special/pow' );
var normalize = require( '@stdlib/number/float64/base/normalize' );
var frac;
var exp;
var x;
var v;
var i;
// Generate denormalized numbers and then normalize them...
for ( i = 0; i < 100; i++ ) {
// Generate a random fraction:
frac = randu( 0.0, 10.0 );
// Generate an exponent on the interval (-308,-324):
exp = discreteUniform( -323, -309 );
// Create a subnormal number (~2.23e-308, ~4.94e-324):
x = frac * pow( 10.0, exp );
// Determine a `y` and an `exp` to "normalize" the subnormal:
v = normalize( x );
console.log( '%d = %d * 2^%d = %d', x, v[0], v[1], v[0]*pow(2.0, v[1]) );
}
```
* * *
## C APIs
### Usage
```c
#include "stdlib/number/float64/base/normalize.h"
```
#### stdlib_base_float64_normalize( x, \*y, \*exp )
Returns a normal number `y` and exponent `exp` satisfying `x = y * 2^exp`.
```c
#include
double y;
int32_t exp;
stdlib_base_float64_normalize( 3.14, &y, &exp );
```
The function accepts the following arguments:
- **x**: `[in] double` input value.
- **y**: `[out] double*` destination for normal number.
- **exp**: `[out] int32_t*` destination for exponent.
```c
void stdlib_base_float64_normalize( const double x, double *y, int32_t *exp );
```
### Examples
```c
#include "stdlib/number/float64/base/normalize.h"
#include
#include
#include
int main( void ) {
double x[] = { 1.0, 3.14, 0.0, -0.0, 3.14e-308, 3.14e308, 1.0/0.0, 0.0/0.0 };
int32_t exp;
double y;
int i;
for ( i = 0; i < 8; i++ ) {
stdlib_base_float64_normalize( x[ i ], &y, &exp );
printf( "%lf => y: %lf, exp: %" PRId32 "\n", x[ i ], y, exp );
}
}
```
[@stdlib/number/float32/base/normalize]: https://github.com/stdlib-js/number/tree/main/float32/base/normalize