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Multiply a single-precision floating-point vector
xby a constantalpha.
import sscal from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-base-sscal@esm/index.mjs';Multiplies a single-precision floating-point vector x by a constant alpha.
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );
sscal( x.length, 5.0, x, 1 );
// x => <Float32Array>[ -10.0, 5.0, 15.0, -25.0, 20.0, 0.0, -5.0, -15.0 ]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 multiply every other value by a constant
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );
sscal( 4, 5.0, x, 2 );
// x => <Float32Array>[ -10.0, 1.0, 15.0, -5.0, 20.0, 0.0, -5.0, -3.0 ]Note that indexing is relative to the first index. To introduce an offset, use typed array views.
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
// 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
// Scale every other value:
sscal( 3, 5.0, x1, 2 );
// x0 => <Float32Array>[ 1.0, -10.0, 3.0, -20.0, 5.0, -30.0 ]If either N or stride is less than or equal to 0, the function returns x unchanged.
Multiplies a single-precision floating-point vector x by a constant alpha using alternative indexing semantics.
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
var x = new Float32Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );
sscal.ndarray( x.length, 5.0, x, 1, 0 );
// x => <Float32Array>[ -10.0, 5.0, 15.0, -25.0, 20.0, 0.0, -5.0, -15.0 ]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 multiply the last three elements of x by a constant
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
var x = new Float32Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );
sscal.ndarray( 3, 5.0, x, 1, x.length-3 );
// x => <Float32Array>[ 1.0, -2.0, 3.0, -20.0, 25.0, -30.0 ]<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import discreteUniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-array-discrete-uniform@esm/index.mjs';
import sscal from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-base-sscal@esm/index.mjs';
var opts = {
'dtype': 'float32'
};
var x = discreteUniform( 10, -100, 100, opts );
console.log( x );
sscal( x.length, 5.0, x, 1 );
console.log( x );
</script>
</body>
</html>@stdlib/blas-base/daxpy: multiply a vectorxby a constant and add the result toy.@stdlib/blas-base/dscal: multiply a double-precision floating-point vector by a constant.@stdlib/blas-base/gscal: multiply a vector by a constant.@stdlib/blas-base/saxpy: multiply a vectorxby a constant and add the result toy.
This package is part of stdlib, a standard library 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.
See LICENSE.
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