120 lines
3.2 KiB
Plaintext
120 lines
3.2 KiB
Plaintext
|
|
{{alias}}( N, x, strideX, y, strideY )
|
|
Computes the dot product of two vectors.
|
|
|
|
The `N`, `strideX`, and `strideY` parameters determine which elements in `x`
|
|
and `y` are accessed at runtime.
|
|
|
|
Indexing is relative to the first index. To introduce an offset, use a typed
|
|
array view.
|
|
|
|
If `N <= 0`, the function returns `0.0`.
|
|
|
|
Parameters
|
|
----------
|
|
N: integer
|
|
Number of indexed elements.
|
|
|
|
x: Array<number>|TypedArray
|
|
First input array.
|
|
|
|
strideX: integer
|
|
Index increment for `x`.
|
|
|
|
y: Array<number>|TypedArray
|
|
Second input array.
|
|
|
|
strideY: integer
|
|
Index increment for `y`.
|
|
|
|
Returns
|
|
-------
|
|
dot: number
|
|
The dot product of `x` and `y`.
|
|
|
|
Examples
|
|
--------
|
|
// Standard usage:
|
|
> var x = [ 4.0, 2.0, -3.0, 5.0, -1.0 ];
|
|
> var y = [ 2.0, 6.0, -1.0, -4.0, 8.0 ];
|
|
> var dot = {{alias}}( x.length, x, 1, y, 1 )
|
|
-5.0
|
|
|
|
// Strides:
|
|
> x = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
|
|
> y = [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ];
|
|
> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> dot = {{alias}}( N, x, 2, y, -1 )
|
|
9.0
|
|
|
|
// Using view offsets:
|
|
> x = new {{alias:@stdlib/array/float64}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
|
|
> y = new {{alias:@stdlib/array/float64}}( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
|
|
> var x1 = new {{alias:@stdlib/array/float64}}( x.buffer, x.BYTES_PER_ELEMENT*1 );
|
|
> var y1 = new {{alias:@stdlib/array/float64}}( y.buffer, y.BYTES_PER_ELEMENT*3 );
|
|
> N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> dot = {{alias}}( N, x1, -2, y1, 1 )
|
|
128.0
|
|
|
|
{{alias}}.ndarray( N, x, strideX, offsetX, y, strideY, offsetY )
|
|
Computes the dot product of two vectors using alternative indexing
|
|
semantics.
|
|
|
|
While typed array views mandate a view offset based on the underlying
|
|
buffer, the `offsetX` and `offsetY` parameters support indexing based on a
|
|
starting index.
|
|
|
|
Parameters
|
|
----------
|
|
N: integer
|
|
Number of indexed elements.
|
|
|
|
x: Array<number>|TypedArray
|
|
First input array.
|
|
|
|
strideX: integer
|
|
Index increment for `x`.
|
|
|
|
offsetX: integer
|
|
Starting index for `x`.
|
|
|
|
y: Array<number>|TypedArray
|
|
Second input array.
|
|
|
|
strideY: integer
|
|
Index increment for `y`.
|
|
|
|
offsetY: integer
|
|
Starting index for `y`.
|
|
|
|
Returns
|
|
-------
|
|
dot: number
|
|
The dot product of `x` and `y`.
|
|
|
|
Examples
|
|
--------
|
|
// Standard usage:
|
|
> var x = [ 4.0, 2.0, -3.0, 5.0, -1.0 ];
|
|
> var y = [ 2.0, 6.0, -1.0, -4.0, 8.0 ];
|
|
> var dot = {{alias}}.ndarray( x.length, x, 1, 0, y, 1, 0 )
|
|
-5.0
|
|
|
|
// Strides:
|
|
> x = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
|
|
> y = [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ];
|
|
> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> dot = {{alias}}.ndarray( N, x, 2, 0, y, 2, 0 )
|
|
9.0
|
|
|
|
// Using offset indices:
|
|
> x = [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ];
|
|
> y = [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ];
|
|
> N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> dot = {{alias}}.ndarray( N, x, -2, x.length-1, y, 1, 3 )
|
|
128.0
|
|
|
|
See Also
|
|
--------
|
|
|