sub

Usage

var sub = require( '@stdlib/math/strided/ops/sub' );

sub( N, dtypeX, x, strideX, dtypeY, y, strideY, dtypeZ, z, strideZ )

Subtracts each element in a strided array x to a corresponding element in a strided array y and assigns the results to elements in a strided array z.

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0 ] );
var y = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var z = new Float64Array( x.length );

sub( x.length, 'float64', x, 1, 'float64', y, 1, 'float64', z, 1 );
// z => <Float64Array>[ -3.0, -1.0, 0.0, -9.0, -1.0 ]

The function accepts the following arguments:

• N: number of indexed elements.
• dtypeX: data type for x.
• x: input array-like object.
• strideX: index increment for x.
• dtypeY: data type for y.
• y: input array-like object.
• strideY: index increment for y.
• dtypeZ: data type for z.
• z: output array-like object.
• strideZ: index increment for z.

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

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0 ] );
var y = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var z = new Float64Array( x.length );

sub( 3, 'float64', x, 2, 'float64', y, -1, 'float64', z, 1 );
// z => <Float64Array>[ -5.0, 1.0, 3.0, 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' );

// Initial arrays...
var x0 = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0 ] );
var y0 = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var z0 = new Float64Array( x0.length );

// Create offset views...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
var y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element
var z1 = new Float64Array( z0.buffer, z0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

sub( 3, 'float64', x1, -2, 'float64', y1, 1, 'float64', z1, 1 );
// z0 => <Float64Array>[ 0.0, 0.0, -4.0, 0.0, -5.0, 0.0 ]

sub.ndarray( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, dtypeZ, z, strideZ, offsetZ )

Subtracts each element in a strided array x to a corresponding element in a strided array y and assigns the results to elements in a strided array z using alternative indexing semantics.

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0 ] );
var y = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
var z = new Float64Array( x.length );

sub.ndarray( x.length, 'float64', x, 1, 0, 'float64', y, 1, 0, 'float64', z, 1, 0 );
// z => <Float64Array>[ -3.0, -1.0, 0.0, -9.0, -1.0 ]

The function accepts the following additional arguments:

• offsetX: starting index for x.
• offsetY: starting index for y.
• offsetZ: starting index for z.

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 in reverse order,

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

var x = new Float64Array( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0 ] );
var y = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
var z = new Float64Array( x.length );

sub.ndarray( 3, 'float64', x, 2, 1, 'float64', y, -1, y.length-1, 'float64', z, 1, 0 );
// z => <Float64Array>[ -5.0, 0.0, -4.0, 0.0, 0.0, 0.0 ]