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dfillEqual

Replace double-precision floating-point strided array elements equal to a provided search element with a specified scalar constant.

Installation

npm install @stdlib/blas-ext-base-dfill-equal

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var dfillEqual = require( '@stdlib/blas-ext-base-dfill-equal' );

dfillEqual( N, searchElement, alpha, x, strideX )

Replaces double-precision floating-point strided array elements equal to a provided search element with a specified scalar constant.

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

var x = new Float64Array( [ -2.0, 0.0, 3.0, 0.0, 4.0, 0.0, -1.0, -3.0 ] );

dfillEqual( x.length, 0.0, 5.0, x, 1 );
// x => <Float64Array>[ -2.0, 5.0, 3.0, 5.0, 4.0, 5.0, -1.0, -3.0 ]

The function has the following parameters:

• N: number of indexed elements.
• searchElement: search element.
• alpha: scalar constant.
• x: input Float64Array.
• strideX: stride length.

The N and stride parameters determine which elements in the strided array are accessed at runtime. For example, to iterate over every other element:

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

var x = new Float64Array( [ 0.0, 1.0, 0.0, -5.0, 4.0, 0.0, -1.0, 0.0 ] );

dfillEqual( 4, 0.0, 5.0, x, 2 );
// x => <Float64Array>[ 5.0, 1.0, 5.0, -5.0, 4.0, 0.0, -1.0, 0.0 ]

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 x0 = new Float64Array( [ 1.0, 0.0, 3.0, 0.0, -5.0, 0.0 ] );

// Create an offset view:
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

// Iterate over every other element:
dfillEqual( 3, 0.0, 5.0, x1, 2 );
// x0 => <Float64Array>[ 1.0, 5.0, 3.0, 5.0, -5.0, 5.0 ]

dfillEqual.ndarray( N, searchElement, alpha, x, strideX, offsetX )

Replaces double-precision floating-point strided array elements equal to a provided search element with a specified scalar constant using alternative indexing semantics.

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

var x = new Float64Array( [ -2.0, 0.0, 3.0, 0.0, 4.0, 0.0, -1.0, -3.0 ] );

dfillEqual.ndarray( x.length, 0.0, 5.0, x, 1, 0 );
// x => <Float64Array>[ -2.0, 5.0, 3.0, 5.0, 4.0, 5.0, -1.0, -3.0 ]

The function has the following additional parameters:

• offsetX: 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:

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

var x = new Float64Array( [ -2.0, 0.0, 3.0, 0.0, 4.0, 0.0, -1.0, -3.0 ] );

dfillEqual.ndarray( x.length, 0.0, 5.0, x, 1, x.length-3 );
// x => <Float64Array>[ -2.0, 0.0, 3.0, 0.0, 4.0, 5.0, -1.0, -3.0 ]

Notes

• If N <= 0, both functions return x unchanged.
• When comparing elements, both functions check for equality using the strict equality operator ===. As a consequence, NaN values are considered distinct, and -0 and +0 are considered the same. To replace NaN values, use @stdlib/blas-ext/base/dfill-nan.

Examples

var zeros = require( '@stdlib/array-zeros' );
var dfillEqual = require( '@stdlib/blas-ext-base-dfill-equal' );

var x = zeros( 10, 'float64' );
console.log( x );

dfillEqual( x.length, 0.0, 5.0, x, 1 );
console.log( x );

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C APIs

Usage

#include "stdlib/blas/ext/base/dfill_equal.h"

stdlib_strided_dfill_equal( N, searchElement, alpha, *X, strideX )

Replaces double-precision floating-point strided array elements equal to a provided search element with a specified scalar constant.

double x[] = { -2.0, 0.0, 3.0, 0.0, 4.0, 0.0, -1.0, -3.0 };

stdlib_strided_dfill_equal( 8, 0.0, 5.0, x, 1 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• searchElement: [in] double search Element.
• alpha: [in] double scalar constant.
• X: [inout] double* input array.
• strideX: [in] CBLAS_INT stride length.

void stdlib_strided_dfill_equal( const CBLAS_INT N, const double searchElement, const double alpha, double *X, const CBLAS_INT strideX );

stdlib_strided_dfill_equal_ndarray( N, searchElement, alpha, *X, strideX, offsetX )

Replaces double-precision floating-point strided array elements equal to a provided search element with a specified scalar constant using alternative indexing semantics.

double x[] = { -2.0, 0.0, 3.0, 0.0, 4.0, 0.0, -1.0, -3.0 };

stdlib_strided_dfill_equal_ndarray( 8, 0.0, 5.0, x, 1, 0 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• searchElement: [in] double search Element.
• alpha: [in] double scalar constant.
• X: [inout] double* input array.
• strideX: [in] CBLAS_INT stride length.
• offsetX: [in] CBLAS_INT starting index.

void stdlib_strided_dfill_equal_ndarray( const CBLAS_INT N, const double searchElement, const double alpha, double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );

Examples

#include "stdlib/blas/ext/base/dfill_equal.h"
#include <stdio.h>

int main( void ) {
    // Create a strided array:
    double x[] = { 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 };

    // Specify the number of indexed elements:
    const int N = 8;

    // Specify a stride:
    const int strideX = 1;

    // Replace equal elements:
    stdlib_strided_dfill_equal( N, 5.0, 10.0, x, strideX );

    // Print the result:
    for ( int i = 0; i < 8; i++ ) {
        printf( "x[ %i ] = %lf\n", i, x[ i ] );
    }
}

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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

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License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.