16-bit half-precision floating-point number.
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> 16-bit half-precision floating-point number.
``bash`
npm install @stdlib/number-float16-ctor
`javascript`
var Float16 = require( '@stdlib/number-float16-ctor' );
#### Float16( value )
16-bit half-precision floating-point number constructor.
`javascript`
var x = new Float16( 5.0 );
// returns
*
#### Float16.name
Static property returning the constructor name.
`javascript`
var str = Float16.name;
// returns 'Float16'
#### Float16.BYTES_PER_ELEMENT
Size (in bytes) of the underlying value.
`javascript`
var nbytes = Float16.BYTES_PER_ELEMENT;
// returns 2
#### Float16.prototype.BYTES_PER_ELEMENT
Size (in bytes) of the underlying value.
`javascript
var x = new Float16( 5.0 );
var nbytes = x.BYTES_PER_ELEMENT;
// returns 2
`
A Float16 instance has the following properties...
#### value
A read-only property returning the underlying value as a number.
`javascript
var x = new Float16( 5.0 );
var v = x.value;
// returns 5.0
`
*
These methods do not mutate a Float16 instance and, instead return a half-precision floating-point number representation.
#### Float16.prototype.toString()
Returns a string representation of a Float16 instance.
`javascript
var x = new Float16( 5.0 );
var str = x.toString();
// returns '5'
x = new Float16( -3.14 );
str = x.toString();
// returns '-3.140625'
`
#### Float16.prototype.toJSON()
Returns a [JSON][json] representation of a Float16 instance. [JSON.stringify()][mdn-json-stringify] implicitly calls this method when stringifying a Float16 instance.
`javascript
var x = new Float16( 5.0 );
var o = x.toJSON();
/*
{
"type": "Float16",
"value": 5.0
}
*/
`
To [revive][mdn-json-parse] a Float16 number from a [JSON][json] string, see [@stdlib/number/float16/reviver][@stdlib/number/float16/reviver].
#### Float16.prototype.valueOf()
Converts a Float16 instance to a primitive value.
`javascript
var x = new Float16( 5.0 );
var v = x.valueOf();
// returns 5.0
x = new Float16( 3.14 );
v = x.valueOf();
// returns 3.140625
`
*
- The underlying value is stored as a half-precision floating-point number [IEEE 754][ieee754] with 1 sign bit, 5 exponent bits, and 10 significand bits.
- A half-precision floating-point number has a range of approximately ±6.55e4 and a precision of about 3-4 decimal digits.
*
`javascript
var Float16 = require( '@stdlib/number-float16-ctor' );
var x = new Float16( 3.14 );
console.log( 'type: %s', typeof x );
// => 'type: object'
console.log( 'str: %s', x );
// => 'str: 3.140625'
console.log( 'value: %d', x.value );
// => 'value: 3.140625'
console.log( 'JSON: %s', JSON.stringify( x ) );
// => 'JSON: {"type":"Float16","value":3.140625}'
`
*
`c`
#include "stdlib/number/float16/ctor.h"
#### stdlib_float16_t
An opaque type definition for a half-precision floating-point number.
`c`
stdlib_float16_t v = stdlib_float16_from_bits( 51648 );
#### stdlib_float16_bits_t
An opaque type definition for a union for accessing the underlying binary representation of a half-precision floating-point number.
`c
#include
stdlib_float16_t x = stdlib_float16_from_bits( 51648 );
stdlib_float16_bits_t y;
y.value = x;
uint16_t bits = y.bits;
// returns 51648
`
The union has the following members:
- value: stdlib_float16_t half-precision floating-point number.uint16_t
- bits: binary representation.
The union allows "type punning"; however, while (more or less) defined in C99, behavior is implementation-defined in C++. For more robust conversion, prefer using explicit helpers for converting to and from binary representation.
#### stdlib_float16_from_bits( bits )
Converts a 16-bit binary representation to a half-precision floating-point number.
`c`
stdlib_float16_t v = stdlib_float16_from_bits( 51648 ); // => -11.5
The function accepts the following arguments:
- bits: [in] uint16_t 16-bit integer corresponding to a binary representation.
#### stdlib_float16_to_bits( x )
Converts a half-precision floating-point number to a 16-bit binary representation.
`c
#include
stdlib_float16_t v = stdlib_float16_from_bits( 51648 ); // => -11.5
uint16_t bits = stdlib_float16_to_bits( v );
`
The function accepts the following arguments:
- x: [in] stdlib_float16_t half-precision floating-point number.
- The stdlib_float16_t type should be treated as a storage and interchange type. Native hardware support for mathematical functions operating on half-precision floating-point numbers varies. As a consequence, for most operations, one should first promote to single-precision (i.e., float), perform the desired operation, and then downcast back to half-precision.
`c
#include "stdlib/number/float16/ctor.h"
#include
#include
int main( void ) {
const stdlib_float16_t x[] = {
stdlib_float16_from_bits( 51648 ), // -11.5
stdlib_float16_from_bits( 18880 ) // 11.5
};
int i;
for ( i = 0; i < 2; i++ ) {
printf( "%d\n", stdlib_float16_to_bits( x[ i ] ) );
}
}
`
*
This package is part of [stdlib][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][stdlib], see the main project [repository][stdlib].
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---
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Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[json]: http://www.json.org/
[mdn-json-stringify]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
[mdn-json-parse]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
[@stdlib/number/float16/reviver]: https://www.npmjs.com/package/@stdlib/number-float16-reviver