Trying to code the fastest algorithm...

[Alex Tweedly]

jbv wrote:

>
>yes, you're right. That was a typo.
>Actually my script is slightly more complex, and I had to strip
>off a couple of things to make the problem easier to explain...
>hence the typo...
>
>So here's a clean version of my code :
>
>put "" into newList
>repeat for each line j in mySentences
>    put j into a
>    replace " " with itemdelimiter in a
>    put "" into b
>
>    repeat for each item i in a
>        get itemoffset(i,myReference)
>        if it>0 then
>            put it & itemdelimiter after b
>        end if
>    end repeat
>    delete last char in b
>
>    if b contains itemdelimiter then
>        put b & cr after newList
>    end if
> end repeat
>
>  
>
>>I don't see anything here which "keeps only those sentences containing
>>more than 1 word" ?
>>    
>>
>
>it's the test :
>    if b contains itemdelimiter then
>which runs about 25% to 30% faster than
>    if number of items of b > 1 then
>  
>
cute !! very nice - I'll remember that one ....

>>Since you're asking for "fastest" algorithm, I assume at least one of
>>these numbers is large - and it's unlikely the same algorithm would
>>excel at both ends of the spectrum .....
>>
>>I have 2 or 3 approaches in mind ... any clues you have on the
>>characteristics of the data would help decide which ones to pursue .....
>>e.g.   build an assoc array of the words which occur in myReferences,
>>where the content of the array element is the word number within the
>>references, and lookup each word in the sentence with that ... should be
>>faster than "itemOffset" but probably not enough to justify it if the
>>number of words in myReferences is very small.
>>
>>    
>>
>
>The "array" approach crossed my mind, but I'm afraid it's not feasable :
>the set of reference words is unpredictable. It is actually derived from a
>sentence entered by the end user, and after some processing / selection
>a set words is extracted from that sentence and then compared with other
>sentences in a data base...
>
>  
>
Still feasible ....( typing straight into email - typos possible )

put empty into myArray
put 0 into count
repeat for each item W in myReference
    add 1 to count
    put W && count & cr after myArray
end repeat
split myArray by CR and space

I'll try some simple experiments based on the figures you gave.... more 
later.

-- 
Alex Tweedly       http://www.tweedly.net

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