93 lines
2.3 KiB
Plaintext
93 lines
2.3 KiB
Plaintext
|
|
||
|
|
{{alias}}( N, x, stride )
|
||
|
|
Computes the sum of the absolute values.
|
||
|
|
|
||
|
|
The sum of absolute values corresponds to the *L1* norm.
|
||
|
|
|
||
|
|
The `N` and `stride` parameters determine which elements in `x` are used to
|
||
|
|
compute the sum.
|
||
|
|
|
||
|
|
Indexing is relative to the first index. To introduce an offset, use typed
|
||
|
|
array views.
|
||
|
|
|
||
|
|
If `N` or `stride` is less than or equal to `0`, the function returns `0`.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
N: integer
|
||
|
|
Number of elements to sum.
|
||
|
|
|
||
|
|
x: Float64Array
|
||
|
|
Input array.
|
||
|
|
|
||
|
|
stride: integer
|
||
|
|
Index increment.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
sum: number
|
||
|
|
Sum of absolute values.
|
||
|
|
|
||
|
|
Examples
|
||
|
|
--------
|
||
|
|
// Standard usage:
|
||
|
|
> var x = new {{alias:@stdlib/array/float64}}( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0 ] );
|
||
|
|
> var sum = {{alias}}( x.length, x, 1 )
|
||
|
|
15.0
|
||
|
|
|
||
|
|
// Sum every other value:
|
||
|
|
> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
||
|
|
> var stride = 2;
|
||
|
|
> sum = {{alias}}( N, x, stride )
|
||
|
|
9.0
|
||
|
|
|
||
|
|
// Use view offset; e.g., starting at 2nd element:
|
||
|
|
> var x0 = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );
|
||
|
|
> var x1 = new {{alias:@stdlib/array/float64}}( x0.buffer, x0.BYTES_PER_ELEMENT*1 );
|
||
|
|
> N = {{alias:@stdlib/math/base/special/floor}}( x0.length / 2 );
|
||
|
|
> sum = {{alias}}( N, x1, stride )
|
||
|
|
12.0
|
||
|
|
|
||
|
|
|
||
|
|
{{alias}}.ndarray( N, x, stride, offset )
|
||
|
|
Computes the sum of absolute values using alternative indexing semantics.
|
||
|
|
|
||
|
|
While typed array views mandate a view offset based on the underlying
|
||
|
|
buffer, the `offset` parameter supports indexing semantics based on a
|
||
|
|
starting index.
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
N: integer
|
||
|
|
Number of elements to sum.
|
||
|
|
|
||
|
|
x: Float64Array
|
||
|
|
Input array.
|
||
|
|
|
||
|
|
stride: integer
|
||
|
|
Index increment.
|
||
|
|
|
||
|
|
offset: integer
|
||
|
|
Starting index.
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
sum: number
|
||
|
|
Sum of absolute values.
|
||
|
|
|
||
|
|
Examples
|
||
|
|
--------
|
||
|
|
// Standard usage:
|
||
|
|
> var x = new {{alias:@stdlib/array/float64}}( [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0 ] );
|
||
|
|
> var sum = {{alias}}.ndarray( x.length, x, 1, 0 )
|
||
|
|
15.0
|
||
|
|
|
||
|
|
// Sum the last three elements:
|
||
|
|
> x = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );
|
||
|
|
> sum = {{alias}}.ndarray( 3, x, -1, x.length-1 )
|
||
|
|
15.0
|
||
|
|
|
||
|
|
See Also
|
||
|
|
--------
|
||
|
|
|