time-to-botec

README.md (6744B)

---

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 # abs
 
 > Compute the [absolute value][absolute-value].
 
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 The [absolute value][absolute-value] is defined as
 
 <!-- <equation class="equation" label="eq:absolute_value" align="center" raw="|x| = \begin{cases} x & \textrm{if}\ x \geq 0 \\ -x & \textrm{if}\ x < 0\end{cases}" alt="Absolute value"> -->
 
 <div class="equation" align="center" data-raw-text="|x| = \begin{cases} x &amp; \textrm{if}\ x \geq 0 \\ -x &amp; \textrm{if}\ x &lt; 0\end{cases}" data-equation="eq:absolute_value">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@61c5f878886bd5b3b98976501c974bf69f575238/lib/node_modules/@stdlib/math/special/abs/docs/img/equation_absolute_value.svg" alt="Absolute value">
     <br>
 </div>
 
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 </section>
 
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 <!-- Package usage documentation. -->
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var abs = require( '@stdlib/math/special/abs' );
 ```
 
 #### abs( x\[, options] )
 
 Computes the [absolute value][absolute-value]. 
 
 ```javascript
 var y = abs( -1.0 );
 // returns 1.0
 ```
 
 The function accepts the following arguments:
 
 -   **x**: input [`ndarray`][@stdlib/ndarray/ctor], array-like object, or number. If provided an [`ndarray`][@stdlib/ndarray/ctor] or array-like object, the function performs element-wise computation.
 -   **options**: function options.
 
 If provided an [`ndarray`][@stdlib/ndarray/ctor], the function returns an [`ndarray`][@stdlib/ndarray/ctor] having the same shape and data type as `x`.
 
 ```javascript
 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`.
 
 ```javascript
 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][@stdlib/ndarray/dtypes]. Only applicable when `x` is either an [`ndarray`][@stdlib/ndarray/ctor] or array-like object. By default, the output array data type is inferred from the input array.
 -   **order**: output array [order][@stdlib/ndarray/orders]. Only applicable when `x` is an [`ndarray`][@stdlib/ndarray/ctor]. By default, the output array order is inferred from the input array.
 
 By default, when provided either an [`ndarray`][@stdlib/ndarray/ctor] or an array-like object, the function returns an object of the same "kind" (either an [`ndarray`][@stdlib/ndarray/ctor] or array-like object, respectively) having the same underlying [data type][@stdlib/ndarray/dtypes]. To specify a different output array [data type][@stdlib/ndarray/dtypes], set the `dtype` option.
 
 ```javascript
 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][absolute-value] and assigns results to a provided output array.
 
 ```javascript
 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`][@stdlib/ndarray/ctor] or array-like object) as the input array. For example, if `x` is an [`ndarray`][@stdlib/ndarray/ctor], `y` must also be an [`ndarray`][@stdlib/ndarray/ctor]. Similarly, if `x` is an array-like object, `y` must also be an array-like object.
 
 TODO: broadcasting discussion and example(s).
 
 </section>
 
 <!-- /.usage -->
 
 <!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
 
 <section class="notes">
 
 </section>
 
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 <!-- Package usage examples. -->
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```javascript
 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 ) );
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
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 <section class="references">
 
 </section>
 
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 <section class="links">
 
 [absolute-value]: https://en.wikipedia.org/wiki/Absolute_value
 
 [@stdlib/ndarray/ctor]: https://www.npmjs.com/package/@stdlib/ndarray-ctor
 
 [@stdlib/ndarray/orders]: https://www.npmjs.com/package/@stdlib/ndarray-orders
 
 [@stdlib/ndarray/dtypes]: https://www.npmjs.com/package/@stdlib/ndarray-dtypes
 
 </section>
 
 <!-- /.links -->