93 lines
2.2 KiB
Plaintext
93 lines
2.2 KiB
Plaintext
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{{alias}}( N, x, stride )
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Computes the sum of the absolute values.
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The sum of absolute values corresponds to the *L1* norm.
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The `N` and `stride` parameters determine which elements in `x` are used to
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compute the sum.
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Indexing is relative to the first index. To introduce an offset, use typed
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array views.
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If `N` or `stride` is less than or equal to `0`, the function returns `0`.
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Parameters
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----------
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N: integer
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Number of elements to sum.
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x: Array<number>|TypedArray
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Input array.
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stride: integer
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Index increment.
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Returns
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-------
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sum: number
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Sum of absolute values.
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Examples
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--------
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// Standard usage:
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> var x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
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> var sum = {{alias}}( x.length, x, 1 )
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19.0
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// Sum every other value:
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> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
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> var stride = 2;
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> sum = {{alias}}( N, x, stride )
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10.0
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// Use view offset; e.g., starting at 2nd element:
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> var x0 = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );
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> var x1 = new {{alias:@stdlib/array/float64}}( x0.buffer, x0.BYTES_PER_ELEMENT*1 );
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> N = {{alias:@stdlib/math/base/special/floor}}( x0.length / 2 );
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> sum = {{alias}}( N, x1, stride )
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12.0
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{{alias}}.ndarray( N, x, stride, offset )
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Computes the sum of absolute values using alternative indexing semantics.
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While typed array views mandate a view offset based on the underlying
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buffer, the `offset` parameter supports indexing semantics based on a
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starting index.
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Parameters
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----------
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N: integer
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Number of elements to sum.
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x: Array<number>|TypedArray
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Input array.
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stride: integer
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Index increment.
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offset: integer
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Starting index.
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Returns
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-------
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sum: number
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Sum of absolute values.
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Examples
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--------
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// Standard usage:
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> var x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
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> var sum = {{alias}}.ndarray( x.length, x, 1, 0 )
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19.0
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// Sum the last three elements:
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> x = [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ];
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> sum = {{alias}}.ndarray( 3, x, -1, x.length-1 )
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15.0
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See Also
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--------
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