feat: add blas/ext/base/dcopy-within
#8234
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Coverage Report
The above coverage report was generated for the changes in this PR. |
kgryte
reviewed
Oct 14, 2025
| var dcopyWithin = require( '@stdlib/blas/ext/base/dcopy-within' ); | ||
| ``` | ||
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| #### dcopyWithin( N, target, x, strideX, start, end ) |
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Splitting the target, start, and end parameters is a bit awkward. Instead, how about
dcopyWithin( N, target, start, end, x, strideX )
kgryte
reviewed
Oct 14, 2025
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| var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] ); | ||
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| dcopyWithin( 3, 2, x, 1, 1, 2 ); |
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A single value copy example isn't super informative. Set N = x.length and copy additional elements.
kgryte
reviewed
Oct 14, 2025
| ```javascript | ||
| var Float64Array = require( '@stdlib/array/float64' ); | ||
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| var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] ); |
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I'd make this a tad more obvious by zeroing the non-indexed values.
kgryte
reviewed
Oct 14, 2025
| var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element | ||
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| // Copy within the view... | ||
| dcopyWithin( 2, 0, x1, 1, 2, 5 ); |
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A 2-element array is not super-informative.
kgryte
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Oct 14, 2025
| // Resolve copy length: | ||
| cl = min( abs( end - start ), N ); | ||
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| // Create a temporary copy of source elements: |
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- While always copying to a temporary array is "safe", it is not the most performant. Ideally, we'd determine whether we actually need to copy. E.g., see .
We only need to copy when writing into the target region would overwrite the values we are wanting to copy. It should be possible to determine this.
- It's not clear why you are needing to use manual
forloops once you actually perform the copy. This is exactly the use case ofdcopy.ndarray. And if you usedcopy, you can get perf benefits due to hardware acceleration. In short, ensure you are appropriately leveraging what we already have rather than reinventing the wheel.
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Resolves stdlib-js/metr-issue-tracker#97
Description
This pull request:
blas/ext/base/dcopy-withinRelated Issues
This pull request:
blas/ext/base/dcopy-withinmetr-issue-tracker#97Questions
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