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!

dmsktrunc

Round each element in a double-precision floating-point strided array toward zero according to a strided mask array.

Installation

npm install @stdlib/math-strided-special-dmsktrunc

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 dmsktrunc = require( '@stdlib/math-strided-special-dmsktrunc' );

dmsktrunc( N, x, sx, m, sm, y, sy )

Rounds each element in a double-precision floating-point strided array x toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array y.

var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );

var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1 ] );
var y = new Float64Array( x.length );

dmsktrunc( x.length, x, 1, m, 1, y, 1 );
// y => <Float64Array>[ 1.0, 2.0, 0.0, 4.0, 0.0 ]

The function accepts the following arguments:

• N: number of indexed elements.
• x: input Float64Array.
• sx: index increment for x.
• m: mask Uint8Array.
• sm: index increment for m.
• y: output Float64Array.
• sy: index increment for y.

The N and stride parameters determine which strided array elements are accessed at runtime. For example, to index every other value in x and to index the first N elements of y in reverse order,

var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );

var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

dmsktrunc( 3, x, 2, m, 2, y, -1 );
// y => <Float64Array>[ 0.0, 0.0, 1.0, 0.0, 0.0, 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' );
var Uint8Array = require( '@stdlib/array-uint8' );

// Initial arrays...
var x0 = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m0 = new Uint8Array( [ 0, 0, 1, 0, 1, 1 ] );
var y0 = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var m1 = new Uint8Array( m0.buffer, m0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element

dmsktrunc( 3, x1, -2, m1, -2, y1, 1 );
// y0 => <Float64Array>[ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0 ]

dmsktrunc.ndarray( N, x, sx, ox, m, sm, om, y, sy, oy )

Rounds each element in a double-precision floating-point strided array x toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array y using alternative indexing semantics.

var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );

var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );

dmsktrunc.ndarray( x.length, x, 1, 0, m, 1, 0, y, 1, 0 );
// y => <Float64Array>[ 1.0, 2.0, 0.0, 4.0, 0.0 ]

The function accepts the following additional arguments:

• ox: starting index for x.
• om: starting index for m.
• oy: starting index for y.

While typed array views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices. For example, to index every other value in x starting from the second value and to index the last N elements in y,

var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );

var x = new Float64Array( [ 1.1, 2.5, -3.5, 4.0, -5.9, 6.4 ] );
var m = new Uint8Array( [ 0, 0, 1, 0, 1, 1 ] );
var y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

dmsktrunc.ndarray( 3, x, 2, 1, m, 2, 1, y, -1, y.length-1 );
// y => <Float64Array>[ 0.0, 0.0, 0.0, 0.0, 4.0, 2.0 ]

Examples

var uniform = require( '@stdlib/random-base-uniform' );
var Float64Array = require( '@stdlib/array-float64' );
var Uint8Array = require( '@stdlib/array-uint8' );
var dmsktrunc = require( '@stdlib/math-strided-special-dmsktrunc' );

var x = new Float64Array( 10 );
var m = new Uint8Array( 10 );
var y = new Float64Array( 10 );

var i;
for ( i = 0; i < x.length; i++ ) {
    x[ i ] = uniform( -10.0, 10.0 );
    if ( uniform( 0.0, 1.0 ) < 0.5 ) {
        m[ i ] = 1;
    }
}
console.log( x );
console.log( m );
console.log( y );

dmsktrunc.ndarray( x.length, x, 1, 0, m, 1, 0, y, -1, y.length-1 );
console.log( y );

---

C APIs

Usage

#include "stdlib/math/strided/special/dmsktrunc.h"

stdlib_strided_dmsktrunc( N, *X, strideX, *Mask, strideMask, *Y, strideY )

Rounds each element in a double-precision floating-point strided array X toward zero according to a strided mask array and assigns the results to elements in a double-precision floating-point strided array Y.

#include <stdint.h>

const double X[] = { 1.1, 2.5, -3.5, 4.0, -5.9, 6.4, -7.0, 8.2 };
const uint8_t Mask[] = { 0, 0, 1, 0, 1, 1, 0, 0 };
double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };

const int64_t N = 4;

stdlib_strided_dmsktrunc( N, X, 2, Mask, 2, Y, 2 );

The function accepts the following arguments:

• N: [in] int64_t number of indexed elements.
• X: [in] double* input array.
• strideX: [in] int64_t index increment for X.
• Mask: [in] uint8_t* mask array.
• strideMask: [in] int64_t index increment for Mask.
• Y: [out] double* output array.
• strideY: [in] int64_t index increment for Y.

void stdlib_strided_dmsktrunc( const int64_t N, const double *X, const int64_t strideX, const uint8_t *Mask, const int64_t strideMask, double *Y, const int64_t strideY );

Examples

#include "stdlib/math/strided/special/dmsktrunc.h"
#include <stdint.h>
#include <stdio.h>

int main( void ) {
    // Create an input strided array:
    const double X[] = { 1.1, 2.5, -3.5, 4.0, -5.9, 6.4, -7.0, 8.2 };

    // Create a mask strided array:
    const uint8_t M[] = { 0, 0, 1, 0, 1, 1, 0, 0 };

    // Create an output strided array:
    double Y[] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };

    // Specify the number of elements:
    const int64_t N = 4;

    // Specify the stride lengths:
    const int64_t strideX = 2;
    const int64_t strideM = 2;
    const int64_t strideY = 2;

    // Compute the results:
    stdlib_strided_dmsktrunc( N, X, strideX, M, strideM, Y, strideY );

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

---

See Also

• @stdlib/math-strided/special/dmskceil: round each element in a double-precision floating-point strided array toward positive infinity according to a strided mask array.
• @stdlib/math-strided/special/dmskfloor: round each element in a double-precision floating-point strided array toward negative infinity according to a strided mask array.
• @stdlib/math-strided/special/dtrunc: round each element in a double-precision floating-point strided array toward zero.
• @stdlib/math-strided/special/smsktrunc: round each element in a single-precision floating-point strided array toward zero according to a strided mask array.

---

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 © 2016-2024. The Stdlib Authors.