On Thu, Feb 22, 2024 at 05:49:59PM +0100, Herve Codina wrote:

Hi Andy, Yury,

On Thu, 22 Feb 2024 17:39:27 +0200
Andy Shevchenko [off-list ref] wrote:

...

quoted

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+ * bitmap_scatter() for the bitmap scatter detailed operations).  

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+ * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n).
+ * The operation bitmap_gather(result, scattered, mask, n) leads to a result
+ * equal or equivalent to src.  

This paragraph...

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+ * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather()
+ * are not bijective.  

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+ * The result and src values are equivalent in that sense that a call to
+ * bitmap_scatter(res, src, mask, n) and a call to bitmap_scatter(res, result,
+ * mask, n) will lead to the same res value.  

...seems duplicating this one.

I would drop the latter one.

I would like to give details about the 'equivalent' in this scatter/gather case.

If you would like - please do! :)
 

If Yury is ok, I can drop this last paragraph.

The original bitmap_onto() description is 3 times longer, and barely
that descriptive. I'm OK with your working and especially pictures.

Thanks,
Yury