2014-08-14 0:17 GMT+02:00 Jon Purdy <evincarofaut...@gmail.com>:
> Sigh. The formatting button in Gmail is directly next to the “Send” button.
> Apologies, list.
>
>
>> It seems like most of the overhead comes from fixed-point arithmetic,
>> actually. Here’s a translation to Kitten with locals:
>
> def meanStd (float float float → float float):
>
> → sum2 sum invLen;
>
> sum ×. invLen → μ;
> μ (sum2 ×. invLen −. μ square) sqrt
>
> You can write this in postfix:
>
> def meanStd (float float float → float float):
>
> → sum2 sum invLen;
>
> sum invLen (×.) → μ;
> μ sum2 invLen (×.) μ square (−.) sqrt
>
> Then easily eliminate μ:
>
> def meanStd (float float float → float float):
>
> → sum2 sum invLen;
>
> sum invLen (×.) dup
> { sum2 invLen (×.) } dip
> square (−.) sqrt
Interesting! But what does the (x.) and (-.) words do?
--
mvh/best regards Björn Lindqvist
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