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Re: vector dot multiply
• Pascal Nicolas
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 Date: 1995-06-09 (10:03) From: Pascal Nicolas Subject: Re: vector dot multiply
```>
> Hi,
>  What would be 1). elegant
>                2). efficient
>  way to write a "dot multiply" function in caml-light?
> This is what I came up with but I am hoping for a better one :
>
> let dot a b = let rec dot_aux a b i sum =
> if i< vect_length a then
>    dot_aux a b (i+1) (sum +. (a.(i) *. b.(i)) )
>  else
>    sum
> in
>  dot_aux a b 0 0.0;;
>
In order to avoid to (re)compute the length of a at each recursive call, you
can modify a little your function as follows

let dot a b = let rec dot_aux a b i sum L =
if i < L then
dot_aux a b (i+1) (sum +. (a.(i) *. b.(i))) L
else
sum
in dot_aux a b 0 0.0 (vect_length a) ;;

--
Pascal NICOLAS                                       LERIA  Université d'ANGERS
Tél : (33) 41 73 54 20             2, Bd Lavoisier 49045 ANGERS cedex 01 FRANCE
E Mail : pn@univ-angers.fr
WWW Url : http://www.univ-angers.fr/~pn/nicolas.html

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