124 lines
3.6 KiB
Plaintext
124 lines
3.6 KiB
Plaintext
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{{alias}}( N, alpha, x, strideX, y, strideY )
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Multiplies a vector `x` by a constant `alpha` and adds the result to `y`.
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The `N` and `stride` parameters determine which elements in `x` and `y` are
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accessed at runtime.
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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 <= 0` or `alpha == 0`, the function returns `y` unchanged.
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Parameters
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----------
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N: integer
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Number of indexed elements.
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alpha: number
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Constant.
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x: Float64Array
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Input array.
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strideX: integer
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Index increment for `x`.
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y: Float64Array
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Destination array.
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strideY: integer
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Index increment for `y`.
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Returns
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-------
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y: Float64Array
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Input array `y`.
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Examples
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--------
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// Standard usage:
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> var x = new {{alias:@stdlib/array/float64}}( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
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> var y = new {{alias:@stdlib/array/float64}}( [ 1.0, 1.0, 1.0, 1.0, 1.0 ] );
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> var alpha = 5.0;
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> {{alias}}( x.length, alpha, x, 1, y, 1 )
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<Float64Array>[ 6.0, 11.0, 16.0, 21.0, 26.0 ]
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// Using `N` and `stride` parameters:
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> x = new {{alias:@stdlib/array/float64}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
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> y = new {{alias:@stdlib/array/float64}}( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
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> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
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> {{alias}}( N, alpha, x, 2, y, -1 )
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<Float64Array>[ 26.0, 16.0, 6.0, 1.0, 1.0, 1.0 ]
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// Using view offsets:
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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 y0 = new {{alias:@stdlib/array/float64}}( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
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> var x1 = new {{alias:@stdlib/array/float64}}( x0.buffer, x0.BYTES_PER_ELEMENT*1 );
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> var y1 = new {{alias:@stdlib/array/float64}}( y0.buffer, y0.BYTES_PER_ELEMENT*3 );
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> N = {{alias:@stdlib/math/base/special/floor}}( x0.length / 2 );
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> {{alias}}( N, 5.0, x1, -2, y1, 1 )
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<Float64Array>[ 40.0, 31.0, 22.0 ]
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> y0
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<Float64Array>[ 7.0, 8.0, 9.0, 40.0, 31.0, 22.0 ]
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{{alias}}.ndarray( N, alpha, x, strideX, offsetX, y, strideY, offsetY )
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Multiplies a vector `x` by a constant `alpha` and adds the result to `y`,
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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 `offsetX` and `offsetY` parameters support indexing semantics
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based on starting indices.
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Parameters
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----------
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N: integer
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Number of indexed elements.
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alpha: number
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Constant.
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x: Float64Array
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Input array.
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strideX: integer
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Index increment for `x`.
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offsetX: integer
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Starting index for `x`.
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y: Float64Array
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Destination array.
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strideY: integer
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Index increment for `y`.
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offsetY: integer
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Starting index for `y`.
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Returns
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-------
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y: Float64Array
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Input array `y`.
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Examples
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--------
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// Standard usage:
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> var x = new {{alias:@stdlib/array/float64}}( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
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> var y = new {{alias:@stdlib/array/float64}}( [ 1.0, 1.0, 1.0, 1.0, 1.0 ] );
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> var alpha = 5.0;
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> {{alias}}.ndarray( x.length, alpha, x, 1, 0, y, 1, 0 )
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<Float64Array>[ 6.0, 11.0, 16.0, 21.0, 26.0 ]
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// Advanced indexing:
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> x = new {{alias:@stdlib/array/float64}}( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
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> y = new {{alias:@stdlib/array/float64}}( [ 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
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> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
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> {{alias}}.ndarray( N, alpha, x, 2, 1, y, -1, y.length-1 )
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<Float64Array>[ 7.0, 8.0, 9.0, 40.0, 31.0, 22.0 ]
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See Also
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--------
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