time-to-botec

README.md (5742B)

---

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 @license Apache-2.0
 
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 # sqrt
 
 > Compute the principal [square root][square-root] of each element in a strided array.
 
 <section class="intro">
 
 The principal [square root][square-root] is defined as
 
 <!-- <equation class="equation" label="eq:principal_square_root" align="center" raw="\sqrt{x^2} = \begin{matrix} x, & \textrm{if}\ x \geq 0\end{matrix}" alt="Principal square root"> -->
 
 <div class="equation" align="center" data-raw-text="\sqrt{x^2} = \begin{matrix} x, &amp; \textrm{if}\ x \geq 0\end{matrix}" data-equation="eq:principal_square_root">
     <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@5de0e834d1b5b074d6df210b9cb492c75c9953a2/lib/node_modules/@stdlib/math/strided/special/sqrt/docs/img/equation_principal_square_root.svg" alt="Principal square root">
     <br>
 </div>
 
 <!-- </equation> -->
 
 </section>
 
 <!-- /.intro -->
 
 <section class="usage">
 
 ## Usage
 
 ```javascript
 var sqrt = require( '@stdlib/math/strided/special/sqrt' );
 ```
 
 #### sqrt( N, x, strideX, y, strideY )
 
 Computes the principal [square root][square-root] of each element in a strided array `x` and assigns the results to elements in a strided array `y`.
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
 var x = new Float64Array( [ 0.0, 4.0, 9.0, 12.0, 24.0 ] );
 
 // Perform operation in-place:
 sqrt( x.length, x, 1, x, 1 );
 // x => <Float64Array>[ 0.0, 2.0, 3.0, ~3.464, ~4.899 ]
 ```
 
 The function accepts the following arguments:
 
 -   **N**: number of indexed elements.
 -   **x**: input array-like object.
 -   **strideX**: index increment for `x`.
 -   **y**: output array-like object.
 -   **strideY**: index increment for `y`.
 
 The `N` and `stride` parameters determine which elements in `x` and `y` are accessed at runtime. For example, to index every other value in `x` and the first `N` elements of `y` in reverse order,
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
 var x = new Float64Array( [ 0.0, 4.0, 9.0, 12.0, 24.0, 64.0 ] );
 var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
 
 sqrt( 3, x, 2, y, -1 );
 // y => <Float64Array>[ ~4.899, 3.0, 0.0, 0.0, 0.0, 0.0 ]
 ```
 
 Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
 // Initial arrays...
 var x0 = new Float64Array( [ 0.0, 4.0, 9.0, 12.0, 24.0, 64.0 ] );
 var y0 = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
 
 // Create offset views...
 var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
 var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element
 
 sqrt( 3, x1, -2, y1, 1 );
 // y0 => <Float64Array>[ 0.0, 0.0, 0.0, 8.0, ~3.464, 2.0 ]
 ```
 
 #### sqrt.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )
 
 Computes the principal [square root][square-root] of each element in a strided array `x` and assigns the results to elements in a strided array `y` using alternative indexing semantics.
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
 var x = new Float64Array( [ 0.0, 4.0, 9.0, 12.0, 24.0 ] );
 var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
 
 sqrt.ndarray( x.length, x, 1, 0, y, 1, 0 );
 // y => <Float64Array>[ 0.0, 2.0, 3.0, ~3.464, ~4.899 ]
 ```
 
 The function accepts the following additional arguments:
 
 -   **offsetX**: starting index for `x`.
 -   **offsetY**: starting index for `y`.
 
 While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the `offsetX` and `offsetY` parameters support indexing semantics based on starting indices. For example, to index every other value in `x` starting from the second value and to index the last `N` elements in `y`,
 
 ```javascript
 var Float64Array = require( '@stdlib/array/float64' );
 
 var x = new Float64Array( [ 0.0, 4.0, 9.0, 12.0, 24.0, 64.0 ] );
 var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
 
 sqrt.ndarray( 3, x, 2, 1, y, -1, y.length-1 );
 // y => <Float64Array>[ 0.0, 0.0, 0.0, 8.0, ~3.464, 2.0 ]
 ```
 
 </section>
 
 <!-- /.usage -->
 
 <section class="notes">
 
 </section>
 
 <!-- /.notes -->
 
 <section class="examples">
 
 ## Examples
 
 <!-- eslint no-undef: "error" -->
 
 ```javascript
 var uniform = require( '@stdlib/random/base/uniform' ).factory;
 var filledarray = require( '@stdlib/array/filled' );
 var dtypes = require( '@stdlib/array/dtypes' );
 var gfillBy = require( '@stdlib/blas/ext/base/gfill-by' );
 var sqrt = require( '@stdlib/math/strided/special/sqrt' );
 
 var dt;
 var x;
 var y;
 var i;
 
 dt = dtypes();
 for ( i = 0; i < dt.length; i++ ) {
     x = filledarray( 0.0, 10, dt[ i ] );
     gfillBy( x.length, x, 1, uniform( 0.0, 100.0 ) );
     console.log( x );
 
     y = filledarray( 0.0, x.length, 'generic' );
     console.log( y );
 
     sqrt.ndarray( x.length, x, 1, 0, y, -1, y.length-1 );
     console.log( y );
     console.log( '' );
 }
 ```
 
 </section>
 
 <!-- /.examples -->
 
 <section class="links">
 
 [mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
 
 [square-root]: https://en.wikipedia.org/wiki/Square_root
 
 </section>
 
 <!-- /.links -->