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abs
Compute the absolute value.
The absolute value is defined as
Installation
npm install @stdlib/math-special-abs
Alternatively,
- To load the package in a website via a
script
tag without installation and bundlers, use the ES Module available on theesm
branch. - If you are using Deno, visit the
deno
branch. - For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the
umd
branch.
The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
Usage
var abs = require( '@stdlib/math-special-abs' );
abs( x[, options] )
Computes the absolute value.
var y = abs( -1.0 );
// returns 1.0
The function accepts the following arguments:
- x: input
ndarray
, array-like object, or number. If provided anndarray
or array-like object, the function performs element-wise computation. - options: function options.
If provided an ndarray
, the function returns an ndarray
having the same shape and data type as x
.
var array = require( '@stdlib/ndarray-array' );
var x = array( [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ); // 2x2
var y = abs( x );
// returns <ndarray>
var v = y.get( 0, 1 );
// returns 2.0
If provided an array-like object, the function returns an array-like object having the same length and data type as x
.
var Float64Array = require( '@stdlib/array-float64' );
var x = new Float64Array( [ -1.0, -2.0 ] );
var y = abs( x );
// returns <Float64Array>[ 1.0, 2.0 ]
x = [ -1.0, -2.0 ];
y = abs( x );
// returns [ 1.0, 2.0 ]
The function accepts the following options
:
- dtype: output array data type. Only applicable when
x
is either anndarray
or array-like object. By default, the output array data type is inferred from the input array. - order: output array order. Only applicable when
x
is anndarray
. By default, the output array order is inferred from the input array.
By default, when provided either an ndarray
or an array-like object, the function returns an object of the same "kind" (either an ndarray
or array-like object, respectively) having the same underlying data type. To specify a different output array data type, set the dtype
option.
var Float32Array = require( '@stdlib/array-float32' );
var x = new Float32Array( [ -1.0, -2.0 ] );
var y = abs( x );
// returns <Float32Array>[ 1.0, 2.0 ]
x = new Float32Array( [ -1.0, -2.0 ] );
y = abs( x, {
'dtype': 'float64'
});
// returns <Float64Array>[ 1.0, 2.0 ]
abs.assign( x, y )
Computes the absolute value and assigns results to a provided output array.
var array = require( '@stdlib/ndarray-array' );
var x = array( [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ); // 2x2
var y = array( [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ); // 2x2
var out = abs.assign( x, y );
// returns <ndarray>
var bool = ( out === y );
// returns true
var v = y.get( 0, 1 );
// returns 2.0
The output array must be the same data "kind" (i.e., ndarray
or array-like object) as the input array. For example, if x
is an ndarray
, y
must also be an ndarray
. Similarly, if x
is an array-like object, y
must also be an array-like object.
TODO: broadcasting discussion and example(s).
Examples
var Float64Array = require( '@stdlib/array-float64' );
var array = require( '@stdlib/ndarray-array' );
var ind2sub = require( '@stdlib/ndarray-ind2sub' );
var abs = require( '@stdlib/math-special-abs' );
// Provide a number...
var v = abs( -1.0 );
console.log( 'x = %d => abs(x) = %d', -1.0, v );
// Provide an array-like object...
var x = new Float64Array( [ -1.0, -2.0, -3.0 ] );
var y = abs( x );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( 'x_%d = %d => abs(x_%d) = %d', i, x[ i ], i, y[ i ] );
}
// Provide an ndarray...
x = array( [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] );
y = abs( x );
var sh = x.shape;
var sub;
for ( i = 0; i < x.length; i++ ) {
sub = ind2sub( sh, i );
console.log( 'x_%d%d = %d => abs(x_%d%d) = %d', sub[ 0 ], sub[ 1 ], x.iget( i ), sub[ 0 ], sub[ 1 ], y.iget( i ) );
}
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
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.