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Element-wise subtraction of two strided arrays.
npm install @stdlib/math-strided-ops-subvar sub = require( '@stdlib/math-strided-ops-sub' );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 ]var uniform = require( '@stdlib/random-base-discrete-uniform' ).factory;
var filledarray = require( '@stdlib/array-filled' );
var filledarrayBy = require( '@stdlib/array-filled-by' );
var sub = require( '@stdlib/math-strided-ops-sub' );
var dt;
var x;
var y;
var z;
var i;
dt = [ 'float64', 'float32', 'int32', 'uint8', 'generic' ];
for ( i = 0; i < dt.length; i++ ) {
x = filledarrayBy( 10, dt[ i ], uniform( 0.0, 10.0 ) );
console.log( x );
y = filledarrayBy( x.length, dt[ i ], uniform( 0.0, 10.0 ) );
console.log( y );
z = filledarray( 0.0, x.length, 'generic' );
console.log( z );
sub.ndarray( x.length, dt[ i ], x, 1, 0, dt[ i ], y, 1, 0, 'generic', z, -1, z.length-1 );
console.log( z );
console.log( '' );
}-
@stdlib/math-strided/ops/add: element-wise addition of two strided arrays. -
@stdlib/math-strided/ops/mul: element-wise multiplication of two strided arrays.
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For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.
See LICENSE.
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