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From Binary String

Create a single-precision floating-point number from an IEEE 754 literal bit representation.

Installation

npm install @stdlib/number-float32-base-from-binary-string

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var fromBinaryStringf = require( '@stdlib/number-float32-base-from-binary-string' );

fromBinaryStringf( bstr )

Creates a single-precision floating-point number from an IEEE 754 literal bit representation.

var bstr = '01000000100000000000000000000000';
var v = fromBinaryStringf( bstr );
// returns 4.0

bstr = '01000000010010010000111111011011';
v = fromBinaryStringf( bstr );
// returns ~3.14

bstr = '11111111011011000011101000110011';
v = fromBinaryStringf( bstr );
// returns ~-3.14e+38

The function handles subnormals.

var bstr = '10000000000000000000000000010110';
var val = fromBinaryStringf( bstr );
// returns ~-3.08e-44

bstr = '00000000000000000000000000000001';
val = fromBinaryStringf( bstr );
// returns ~1.40e-45

The function handles special values.

var bstr = '00000000000000000000000000000000';
var val = fromBinaryStringf( bstr );
// returns 0.0

bstr = '10000000000000000000000000000000';
val = fromBinaryStringf( bstr );
// returns -0.0

bstr = '01111111110000000000000000000000';
val = fromBinaryStringf( bstr );
// returns NaN

bstr = '01111111100000000000000000000000';
val = fromBinaryStringf( bstr );
// returns Infinity

bstr = '11111111100000000000000000000000';
val = fromBinaryStringf( bstr );
// returns -Infinity

Examples

var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var pow = require( '@stdlib/math-base-special-pow' );
var toFloat32 = require( '@stdlib/number-float64-base-to-float32' );
var toBinaryStringf = require( '@stdlib/number-float32-base-to-binary-string' );
var fromBinaryStringf = require( '@stdlib/number-float32-base-from-binary-string' );

var frac;
var sign;
var exp;
var b;
var x;
var y;
var i;

// Convert random numbers to IEEE 754 literal bit representations and then convert them back...
for ( i = 0; i < 100; i++ ) {
    if ( randu() < 0.5 ) {
        sign = -1.0;
    } else {
        sign = 1.0;
    }
    frac = randu() * 10.0;
    exp = round( randu()*100.0 );
    if ( randu() < 0.5 ) {
        exp = -exp;
    }
    x = sign * frac * pow( 2.0, exp );
    x = toFloat32( x );

    b = toBinaryStringf( x );
    y = fromBinaryStringf( b );

    console.log( '%d => %s => %d', x, b, y );
    console.log( x === y );
}

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See Also

• @stdlib/number-float32/base/to-binary-string: return a string giving the literal bit representation of a single-precision floating-point number.
• @stdlib/number-float64/base/from-binary-string: create a double-precision floating-point number from a literal bit representation.

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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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.