149 lines
5.0 KiB
Plaintext
149 lines
5.0 KiB
Plaintext
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{{alias}}( fcns, types, data, nargs, nin, nout )
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Returns a strided array function interface which performs multiple dispatch.
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Without offsets, a strided array function interface has the following
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signature:
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f( N, x, strideX, y, strideY, ... )
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where
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- N: number of indexed elements.
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- x: strided array.
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- strideX: index increment for `x`.
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- y: strided array.
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- strideY: index increment for `y`.
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- ...: additional strided arrays and associated strides.
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The number of parameters is derived from `nargs`, the number of input
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strided arrays is derived from `nin`, and the number of output strided
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arrays is derived from `nout`.
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Without offsets, the number of parameters must obey the following relation:
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nargs = 2*(nout+nin) + 1
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With offsets, the number of parameters must obey the following relation:
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nargs = 3*(nout+nin) + 1
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With offsets, a strided array function interface has the following
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signature:
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f( N, x, strideX, offsetX, y, strideY, offsetY, ... )
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where
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- N: number of indexed elements.
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- x: strided array.
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- strideX: index increment for `x`.
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- offsetX: starting index for `x`.
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- y: strided array.
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- strideY: index increment for `y`.
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- offsetY: starting index for `y`.
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- ...: additional strided arrays and associated strides and offsets.
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The choice of which strided array function interface to return depends on
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the use case. The former is suitable for typed array views; while the latter
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affords alternative indexing semantics more suitable for n-dimensional
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arrays (ndarrays).
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Parameters
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----------
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fcns: Function|ArrayLikeObject<Function>
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List of strided array functions. Without offsets, a strided array
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function should have the following signature:
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f( arrays, shape, strides, data )
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where
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- arrays: array containing strided input and output arrays.
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- shape: array containing a single element, the number of indexed
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elements.
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- strides: array containing the stride lengths for the strided input and
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output arrays.
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- data: strided array function data (e.g., a callback).
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With offsets, a strided array function should have the following
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signature:
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f( arrays, shape, strides, offsets, data )
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where
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- offsets: array containing the starting indices (i.e., index offsets)
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for the strided input and output arrays.
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For convenience, a single strided array function may be provided which
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will be invoked whenever the strided array argument data types match a
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sequence of types in `types`. Providing a single strided array function
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is particularly convenient for the case where, regardless of array data
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types, traversing arrays remains the same, but the strided array
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function `data` differs (e.g., callbacks which differ based on the array
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data types).
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types: ArrayLikeObject<string>
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One-dimensional list of strided array argument data types.
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data: ArrayLikeObject|null
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Strided array function data (e.g., callbacks). If `null`, a returned
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strided array function interface does **not** provide a `data` argument
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to an invoked strided array function.
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nargs: integer
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Total number of strided array function interface arguments (including
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strides and offsets).
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nin: integer
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Number of input strided arrays.
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nout: integer
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Number of output strided arrays.
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Returns
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-------
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fcn: Function
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Strided array function interface.
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Examples
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--------
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// Define strided array argument data types:
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> var t = [ 'float64', 'float64', 'float32', 'float32' ];
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// Define a list of strided array function data (callbacks):
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> var d = [ {{alias:@stdlib/math/base/special/abs}}, {{alias:@stdlib/math/base/special/absf}} ];
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// Create a strided array function interface for applying unary callbacks:
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> var f = {{alias}}( {{alias:@stdlib/strided/base/unary}}, t, d, 5, 1, 1 );
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// Create an input strided array:
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> var x = new {{alias:@stdlib/array/float64}}( [ -1.0, -2.0, -3.0, -4.0 ] );
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// Create an output strided array:
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> var y = new {{alias:@stdlib/array/float64}}( [ 0.0, 0.0, 0.0, 0.0 ] );
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// Compute the element-wise absolute value:
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> f( x.length, x, 1, y, 1 );
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> y
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<Float64Array>[ 1.0, 2.0, 3.0, 4.0 ]
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// Create a strided array function interface supporting offsets:
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> f = {{alias}}( {{alias:@stdlib/strided/base/unary}}.ndarray, t, d, 7, 1, 1 );
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// Create an input strided array:
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> x = new {{alias:@stdlib/array/float64}}( [ -1.0, -2.0, -3.0, -4.0 ] );
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// Create an output strided array:
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> y = new {{alias:@stdlib/array/float64}}( [ 0.0, 0.0, 0.0, 0.0 ] );
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// Compute the element-wise absolute value starting from the third element:
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> f( x.length/2, x, 1, 2, y, 1, 2 );
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> y
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<Float64Array>[ 0.0, 0.0, 3.0, 4.0 ]
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See Also
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--------
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