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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

dnancount

NPM version Build Status Coverage Status

Calculate the number of non-NaN elements in a double-precision floating-point strided array.

Usage

import dnancount from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-dnancount@esm/index.mjs';

The previous example will load the latest bundled code from the esm branch. Alternatively, you may load a specific version by loading the file from one of the tagged bundles. For example,

import dnancount from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-dnancount@v0.0.0-esm/index.mjs';

dnancount( N, x, strideX )

Computes the number of non-NaN elements in a double-precision floating-point strided array.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';

var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] );

var v = dnancount( x.length, x, 1 );
// returns 3

The function has the following parameters:

  • N: number of indexed elements.
  • x: input Float64Array.
  • strideX: stride length for x.

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

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';

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

var v = dnancount( 4, x, 2 );
// returns 2

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

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';

var x0 = new Float64Array( [ 2.0, 1.0, NaN, -2.0, 3.0, 4.0, NaN, NaN ] );
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var v = dnancount( 4, x1, 2 );
// returns 3

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

Computes the number of non-NaN elements in a double-precision floating-point strided array using alternative indexing semantics.

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';

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

var v = dnancount.ndarray( 4, x, 2, 1 );
// returns 3

The function has the following additional parameter:

  • offsetX: starting index for x.

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 count every other element in x starting from the second element,

import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';

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

var v = dnancount.ndarray( 4, x, 2, 1 );
// returns 3

Notes

  • If N <= 0, both functions return 0.

Examples

<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">

import uniform from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-uniform@esm/index.mjs';
import filledarrayBy from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-filled-by@esm/index.mjs';
import bernoulli from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-bernoulli@esm/index.mjs';
import dnancount from 'https://cdn.jsdelivr.net/gh/stdlib-js/blas-ext-base-dnancount@esm/index.mjs';

function rand() {
    if ( bernoulli( 0.8 ) < 1 ) {
        return NaN;
    }
    return uniform( -50.0, 50.0 );
}

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

var v = dnancount( x.length, x, 1 );
console.log( v );

</script>
</body>
</html>

Notice

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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2026. The Stdlib Authors.
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