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dnone

Test whether every element in a double-precision floating-point strided array is falsy.

Installation

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

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

dnone( N, x, strideX )

Tests whether every element in a double-precision floating-point strided array is falsy.

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

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

var v = dnone( x.length, x, 1 );
// returns false

The function has the following parameters:

• N: number of indexed elements.
• 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 test every other element:

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

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

var v = dnone( 3, x, 2 );
// returns false

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

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

var x0 = new Float64Array( [ 0.0, 0.0, 1.0, 0.0, 0.0, 1.0 ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var v = dnone( 3, x1, 2 );
// returns false

dnone.ndarray( N, x, strideX, offsetX )

Tests whether every element in a double-precision floating-point strided array is falsy using alternative indexing semantics.

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

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

var v = dnone.ndarray( x.length, x, 1, 0 );
// returns false

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 test every other element starting from the second element:

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

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

var v = dnone.ndarray( 3, x, 2, 1 );
// returns false

Notes

• If N <= 0, both functions return true.
• Both functions explicitly treat NaN values as falsy.

Examples

var bernoulli = require( '@stdlib/random-array-bernoulli' );
var dnone = require( '@stdlib/blas-ext-base-dnone' );

var x = bernoulli( 10, 0.5, {
    'dtype': 'float64'
});
console.log( x );

var out = dnone( x.length, x, 1 );
console.log( out );

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C APIs

Usage

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

stdlib_strided_dnone( N, *X, strideX )

Tests whether every element in a double-precision floating-point strided array is falsy.

const double x[] = { 0.0, 0.0, 1.0, 1.0 };

bool result = stdlib_strided_dnone( 4, x, 1 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• X: [in] double* input array.
• strideX: [in] CBLAS_INT stride length.

bool stdlib_strided_dnone( const CBLAS_INT N, const double *X, const CBLAS_INT strideX );

stdlib_strided_dnone_ndarray( N, *X, strideX, offsetX )

Tests whether every element in a double-precision floating-point strided array is falsy using alternative indexing semantics.

const double x[] = { 0.0, 0.0, 1.0, 1.0 };

bool result = stdlib_strided_dnone_ndarray( 4, x, 1, 0 );

The function accepts the following arguments:

• N: [in] CBLAS_INT number of indexed elements.
• X: [in] double* input array.
• strideX: [in] CBLAS_INT stride length.
• offsetX: [in] CBLAS_INT starting index.

bool stdlib_strided_dnone_ndarray( const CBLAS_INT N, const double *X, const CBLAS_INT strideX, const CBLAS_INT offsetX );

• Both functions explicitly treat NaN values as falsy.

Examples

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

int main( void ) {
    // Create a strided array:
    const double x[] = { 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 0.0 };

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

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

    // Test whether every element is falsy:
    bool result = stdlib_strided_dnone( N, x, strideX );

    // Print the result:
    printf( "Result: %s\n", result ? "true" : "false" );
}

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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.