@stdlib/blas-base-wasm-ccopy

v0.1.1

Published

17 days ago

Copy values from one complex single-precision floating-point vector to another complex single-precision floating-point vector.

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ccopy

Copy values from one complex single-precision floating-point vector to another complex single-precision floating-point vector.

Installation

npm install @stdlib/blas-base-wasm-ccopy

Usage

var ccopy = require( '@stdlib/blas-base-wasm-ccopy' );

ccopy.main( N, x, strideX, y, strideY )

Copies values from x into y.

var Complex64Array = require( '@stdlib/array-complex64' );

// Define strided arrays...
var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Perform operation:
ccopy.main( x.length, x, 1, y, 1 );
// y => <Complex64Array>[ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ]

The function has the following parameters:

N: number of indexed elements.
x: input Complex64Array.
strideX: index increment for x.
y: output Complex64Array.
strideY: index increment for y.

The N and stride parameters determine how values from x are copied into y. For example, to copy every other value in x into the first N elements of y in reverse order,

var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy.main( 2, x, -2, y, 1 );
// y => <Complex64Array>[ 5.0, 6.0, 1.0, 2.0, 0.0, 0.0, 0.0, 0.0 ]

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

var Complex64Array = require( '@stdlib/array-complex64' );

// Initial arrays...
var x0 = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y0 = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

// Create offset views...
var x1 = new Complex64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Complex64Array( y0.buffer, y0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

// Copy every other value from `x1` into `y1` in reverse order...
ccopy.main( 2, x1, -2, y1, 1 );
// y0 => <Complex64Array>[ 0.0, 0.0, 0.0, 0.0, 7.0, 8.0, 3.0, 4.0 ]

ccopy.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )

Copies values from x into y using alternative indexing semantics.

var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy.ndarray( x.length, x, 1, 0, y, 1, 0 );
// y => <Complex64Array>[ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ]

The function has the following additional parameters:

offsetX: starting index for x.
offsetY: 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 copy every other value in x starting from the second value into the last N elements in y where x[i] = y[n], x[i+2] = y[n-1],...,

var Complex64Array = require( '@stdlib/array-complex64' );

var x = new Complex64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
var y = new Complex64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

ccopy.ndarray( 2, x, 2, 1, y, -1, y.length-1 );
// y => <Complex64Array>[ 0.0, 0.0, 0.0, 0.0, 7.0, 8.0, 3.0, 4.0 ]

Module

ccopy.Module( memory )

Returns a new WebAssembly module wrapper instance which uses the provided WebAssembly memory instance as its underlying memory.

var Memory = require( '@stdlib/wasm-memory' );

// Create a new memory instance with an initial size of 10 pages (640KiB) and a maximum size of 100 pages (6.4MiB):
var mem = new Memory({
    'initial': 10,
    'maximum': 100
});

// Create a BLAS routine:
var mod = new ccopy.Module( mem );
// returns <Module>

// Initialize the routine:
mod.initializeSync();

ccopy.Module.prototype.main( N, xp, sx, yp, sy )

Copies values from x into y.

var Memory = require( '@stdlib/wasm-memory' );
var oneTo = require( '@stdlib/array-one-to' );
var zeros = require( '@stdlib/array-zeros' );
var bytesPerElement = require( '@stdlib/ndarray-base-bytes-per-element' );
var Complex64Array = require( '@stdlib/array-complex64' );
var reinterpretComplex64 = require( '@stdlib/strided-base-reinterpret-complex64' );
var ccopy = require( '@stdlib/blas-base-wasm-ccopy' );

// Create a new memory instance with an initial size of 10 pages (320KiB) and a maximum size of 100 pages (6.4MiB):
var mem = new Memory({
    'initial': 10,
    'maximum': 100
});

// Create a BLAS routine:
var mod = new ccopy.Module( mem );
// returns <Module>

// Initialize the routine:
mod.initializeSync();

// Define a vector data type:
var dtype = 'complex64';

// Specify a vector length:
var N = 5;

// Define a pointer (i.e., byte offset) for storing the input vector:
var xptr = 0;

// Define a pointer (i.e., byte offset) for storing the output vector:
var yptr = N * bytesPerElement( dtype );

// Write vector values to module memory:
var xbuf = oneTo( N*2, 'float32' );
var x = new Complex64Array( xbuf.buffer );
mod.write( xptr, x );

var ybuf = zeros( N*2, 'float32' );
var y = new Complex64Array( ybuf.buffer );
mod.write( yptr, y );

// Perform computation:
mod.main( N, xptr, 1, yptr, 1 );

// Read out the results:
var view = zeros( N, dtype );
mod.read( yptr, view );

console.log( reinterpretComplex64( view, 0 ) );
// => <Float32Array>[ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 ]

The function has the following parameters:

N: number of indexed elements.
xp: input Complex64Array pointer (i.e., byte offset).
sx: index increment for x.
yp: output Complex64Array pointer (i.e., byte offset).
sy: index increment for y.

ccopy.Module.prototype.ndarray( N, xp, sx, ox, yp, sy, oy )

Copies values from x into y using alternative indexing semantics.

var Memory = require( '@stdlib/wasm-memory' );
var oneTo = require( '@stdlib/array-one-to' );
var zeros = require( '@stdlib/array-zeros' );
var bytesPerElement = require( '@stdlib/ndarray-base-bytes-per-element' );
var Complex64Array = require( '@stdlib/array-complex64' );
var reinterpretComplex64 = require( '@stdlib/strided-base-reinterpret-complex64' );
var ccopy = require( '@stdlib/blas-base-wasm-ccopy' );

// Create a new memory instance with an initial size of 10 pages (320KiB) and a maximum size of 100 pages (6.4MiB):
var mem = new Memory({
    'initial': 10,
    'maximum': 100
});

// Create a BLAS routine:
var mod = new ccopy.Module( mem );
// returns <Module>

// Initialize the routine:
mod.initializeSync();

// Define a vector data type:
var dtype = 'complex64';

// Specify a vector length:
var N = 5;

// Define a pointer (i.e., byte offset) for storing the input vector:
var xptr = 0;

// Define a pointer (i.e., byte offset) for storing the output vector:
var yptr = N * bytesPerElement( dtype );

// Write vector values to module memory:
var xbuf = oneTo( N*2, 'float32' );
var x = new Complex64Array( xbuf.buffer );
mod.write( xptr, x );

var ybuf = zeros( N*2, 'float32' );
var y = new Complex64Array( ybuf.buffer );
mod.write( yptr, y );

// Perform computation:
mod.ndarray( N, xptr, 1, 0, yptr, 1, 0 );

// Read out the results:
var view = zeros( N, dtype );
mod.read( yptr, view );

console.log( reinterpretComplex64( view, 0 ) );
// => <Float32Array>[ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 ]

The function has the following additional parameters:

ox: starting index for x.
oy: starting index for y.

Notes

If N <= 0, both functions return y unchanged.
This package implements routines using WebAssembly. When provided arrays which are not allocated on a ccopy module memory instance, data must be explicitly copied to module memory prior to computation. Data movement may entail a performance cost, and, thus, if you are using arrays external to module memory, you should prefer using @stdlib/blas-base/ccopy. However, if working with arrays which are allocated and explicitly managed on module memory, you can achieve better performance when compared to the pure JavaScript implementations found in @stdlib/blas/base/ccopy. Beware that such performance gains may come at the cost of additional complexity when having to perform manual memory management. Choosing between implementations depends heavily on the particular needs and constraints of your application, with no one choice universally better than the other.
ccopy() corresponds to the BLAS level 1 function ccopy.

Examples

var oneTo = require( '@stdlib/array-one-to' );
var zeros = require( '@stdlib/array-zeros' );
var Complex64Array = require( '@stdlib/array-complex64' );
var reinterpretComplex64 = require( '@stdlib/strided-base-reinterpret-complex64' );
var ccopy = require( '@stdlib/blas-base-wasm-ccopy' );

// Specify a vector length:
var N = 5;

var xbuf = oneTo( N*2, 'float32' );
var x = new Complex64Array( xbuf.buffer );

var ybuf = zeros( N*2, 'float32' );
var y = new Complex64Array( ybuf.buffer );

// Perform computation:
ccopy.ndarray( N, x, 1, 0, y, -1, N-1 );

// Print the results:
console.log( reinterpretComplex64( y, 0 ) );
// => <Float32Array>[ 9.0, 10.0, 7.0, 8.0, 5.0, 6.0, 3.0, 4.0, 1.0, 2.0 ]

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.