dlaset

Set the off-diagonal elements and the diagonal elements of a double-precision floating-point matrix to specified values.

Installation

npm install @stdlib/lapack-base-dlaset

Usage

var dlaset = require( '@stdlib/lapack-base-dlaset' );

dlaset( order, uplo, M, N, alpha, beta, A, LDA )

Sets the off-diagonal elements and the diagonal elements of a double-precision floating-point matrix to specified values.

var Float64Array = require( '@stdlib/array-float64' );

var A = new Float64Array( 4 );

dlaset( 'row-major', 'all', 2, 2, 2.0, 1.0, A, 2 );
// A => <Float64Array>[ 1.0, 2.0, 2.0, 1.0 ]

The function has the following parameters:

• order: storage layout.
• uplo: specifies whether to set the upper or lower triangular/trapezoidal part of a matrix A.
• M: number of rows in A.
• N: number of columns in A.
• alpha: value assigned to off-diagonal elements.
• beta: value assigned to diagonal elements.
• A: input Float64Array.
• LDA: stride of the first dimension of A (a.k.a., leading dimension of the matrix A).

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

var Float64Array = require( '@stdlib/array-float64' );

// Initial array:
var A0 = new Float64Array( 5 );

// Create offset view:
var A1 = new Float64Array( A0.buffer, A0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

dlaset( 'row-major', 'all', 2, 2, 2.0, 1.0, A1, 2 );
// A0 => <Float64Array>[ 0.0, 1.0, 2.0, 2.0, 1.0 ]

dlaset.ndarray( uplo, M, N, alpha, beta, A, sa1, sa2, oa )

Sets the off-diagonal elements and the diagonal elements of a double-precision floating-point matrix to specified values using alternative indexing semantics.

var Float64Array = require( '@stdlib/array-float64' );

var A = new Float64Array( 4 );

dlaset.ndarray( 'all', 2, 2, 2.0, 1.0, A, 2, 1, 0 );
// A => <Float64Array>[ 1.0, 2.0, 2.0, 1.0 ]

The function has the following parameters:

• uplo: specifies whether to set the upper or lower triangular/trapezoidal part of a matrix A.
• M: number of rows in A.
• N: number of columns in A.
• alpha: value assigned to off-diagonal elements.
• beta: value assigned to diagonal elements.
• A: input Float64Array.
• sa1: stride of the first dimension of A.
• sa2: stride of the second dimension of A.
• oa: starting index for A.

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,

var Float64Array = require( '@stdlib/array-float64' );

var A = new Float64Array( 5 );

dlaset.ndarray( 'all', 2, 2, 2.0, 1.0, A, 2, 1, 1 );
// A => <Float64Array>[ 0.0, 1.0, 2.0, 2.0, 1.0 ]

Notes

• dlaset() corresponds to the LAPACK routine dlaset.

Examples

var ndarray2array = require( '@stdlib/ndarray-base-to-array' );
var uniform = require( '@stdlib/random-array-discrete-uniform' );
var numel = require( '@stdlib/ndarray-base-numel' );
var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );
var dlaset = require( '@stdlib/lapack-base-dlaset' );

var shape = [ 5, 8 ];
var order = 'row-major';
var strides = shape2strides( shape, order );

var N = numel( shape );

var A = uniform( N, -10, 10, {
    'dtype': 'float64'
});
console.log( ndarray2array( A, shape, strides, 0, order ) );

dlaset( order, 'all', shape[ 0 ], shape[ 1 ], 2.0, 3.0, A, strides[ 0 ] );
console.log( ndarray2array( A, shape, strides, 0, order ) );

C APIs

Usage

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Examples

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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 © 2016-2026. The Stdlib Authors.