Re: map-array

[cartier@math.uqam.ca (Guillaume Cartier)]

<---
| Based on the Code of Bill St.Clair for faster-climits I tried to write a
| general map-array function,
| both a mcl specific and a portable version.
| 
| Then I compared this construct to mapc for sequences
| 
| To my surprise, the mapping an array was slower than mapping over a list.
| Am I missing something ?
--->

Yes!

It is true that access to a specific element of an array in generaly faster
than access to a specific element of a list. But, in this case, we are not accessing elements individualy but mapping over the whole structure.

Mapping over an array involves accessing every element individualy (each
time having to do at least a multiplication and an addition) where as
mapping over a list involves simple pointer indirections which are very
fast.

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