README

sfill

Fill a single-precision floating-point strided array with a specified scalar constant.

Installation

npm install @stdlib/blas-ext-base-sfill

Usage

var sfill = require( '@stdlib/blas-ext-base-sfill' );

sfill( N, alpha, x, stride )

Fills a single-precision floating-point strided array x with a specified scalar constant alpha.

var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

sfill( x.length, 5.0, x, 1 );
// x => <Float32Array>[ 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 ]

The function has the following parameters:

N: number of indexed elements.
alpha: scalar constant.
x: input Float32Array.
stride: index increment.

The N and stride parameters determine which elements in x are accessed at runtime. For example, to fill every other element

var Float32Array = require( '@stdlib/array-float32' );
var floor = require( '@stdlib/math-base-special-floor' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );
var N = floor( x.length / 2 );

sfill( N, 5.0, x, 2 );
// x => <Float32Array>[ 5.0, 1.0, 5.0, -5.0, 5.0, 0.0, 5.0, -3.0 ]

Note that indexing is relative to the first index. To introduce an offset, use typed array views.

var Float32Array = require( '@stdlib/array-float32' );
var floor = require( '@stdlib/math-base-special-floor' );

// Initial array...
var x0 = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

// Create an offset view...
var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var N = floor( x0.length/2 );

// Fill every other element...
sfill( N, 5.0, x1, 2 );
// x0 => <Float32Array>[ 1.0, 5.0, 3.0, 5.0, 5.0, 5.0 ]

sfill.ndarray( N, alpha, x, stride, offset )

Fills a single-precision floating-point strided array x with a specified scalar constant alpha using alternative indexing semantics.

var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

sfill.ndarray( x.length, 5.0, x, 1, 0 );
// x => <Float32Array>[ 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0, 5.0 ]

The function has the following additional parameters:

offset: starting index.

While typed array views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of x

var Float32Array = require( '@stdlib/array-float32' );

var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );

sfill.ndarray( 3, 5.0, x, 1, x.length-3 );
// x => <Float32Array>[ 1.0, -2.0, 3.0, 5.0, 5.0, 5.0 ]

Notes

If N <= 0, both functions return x unchanged.

Examples

var round = require( '@stdlib/math-base-special-round' );
var randu = require( '@stdlib/random-base-randu' );
var Float32Array = require( '@stdlib/array-float32' );
var sfill = require( '@stdlib/blas-ext-base-sfill' );

var rand;
var sign;
var x;
var i;

x = new Float32Array( 10 );
for ( i = 0; i < x.length; i++ ) {
    rand = round( randu()*100.0 );
    sign = randu();
    if ( sign < 0.5 ) {
        sign = -1.0;
    } else {
        sign = 1.0;
    }
    x[ i ] = sign * rand;
}
console.log( x );

sfill( x.length, 5.0, x, 1 );
console.log( x );

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.

@stdlib/blas-ext-base-sfill

Usage no npm install needed!