Mr. Boss -

running your code, I get

   'kitten'Levdist 'sitting'
|domain error: Levdist
|   'a b'    =:t}.&.>a;b
|Levdist[:7]

because of the global assignment on this line.  Changing "=:" to "=." seems
to fix it.

Regards,

Mr. McCormick

2009/4/28 R.E. Boss <[email protected]>

> Correction:
>
> Levdist=: 4 : 0
> 'a b'=. (\:#&>) x;y
> p=: 2 0$0
> z=.0
> while. a *.&# b do.
>  t=. a ((i.<./)@:(+...@#)([>:@,~{)])@:i. b
>  z=.z+<:>./t
>  p=:p,.t {.&.> a;b
>  'a b'=: t }.&.> a;b
> end.
> if. a +&# b do. p=:p,.a;b end.
> z=.z+ a +&# b
> )
>
>   'kitten'Levdist 'sitting'
> 3
>
>   p
> +--+-+-+--+-+
> |si|t|t|in|g|
> +--+-+-+--+-+
> |ki|t|t|en| |
> +--+-+-+--+-+
>
>
> R.E. Boss
>
>
> > -----Oorspronkelijk bericht-----
> > Van: [email protected] [mailto:programming-
> > [email protected]] Namens R.E. Boss
> > Verzonden: dinsdag 28 april 2009 19:52
> > Aan: 'Programming forum'
> > Onderwerp: Re: [Jprogramming] Levenshtein distance
> >
> > Levdist=: 4 : 0
> > 'a b'=. (\:#&>) x;y
> > p=: 2 0$0
> > z=.0
> > while. a *.&# b do.
> >  t=. a ((i.<./)@:(+...@#)([>:@,~{)])@:i. b
> >  z=.z+<:>./t
> >  p=:p,.t {.&.> a;b
> >  'a b'=. t }.&.> a;b
> > end.
> > z=.z+ a +&# b
> > )
> >
> >    'excused' Levdist 'exhausted'
> > 3
> >
> >    p  NB. exhibits distance cf. http://www.levenshtein.net/index.html
> > +-+-+---+-+--+-+
> > |e|x|hau|s|te|d|
> > +-+-+---+-+--+-+
> > |e|x|cu |s|e |d|
> > +-+-+---+-+--+-+
> >
> >    'levenshtein' Levdist 'malenstein'
> > 5     NB. is the right answer
> >
> >    p
> > +---+-+---+-+--+-+-+-+
> > |l  |e|ven|s|ht|e|i|n|
> > +---+-+---+-+--+-+-+-+
> > |mal|e|n  |s|t |e|i|n|
> > +---+-+---+-+--+-+-+-+
> >
> >
> >    ts'''excused'' Levdist&(100,@(#,:)]) ''exhausted'''
> > 0.062798674 88000
> >
> >    ts'''excused'' levdist&(100,@(#,:)]) ''exhausted'''
> > |limit error: levdist
> > |       stap"1 xs,"0/&}.ys
> >
> >    ts'''excused'' levdist&(10,@(#,:)]) ''exhausted'''
> > 0.34071143 2.6334221e8
> >
> >    ts'''excused'' Levdist&(10,@(#,:)]) ''exhausted'''
> > 0.0019793917 4672
> >
> >    'excused' (Levdist-:levdist)&(10,@(#,:)]) 'exhausted'
> > 1
> >
> >
> > R.E Boss
> >
> >
> > > -----Oorspronkelijk bericht-----
> > > Van: [email protected] [mailto:programming-
> > > [email protected]] Namens Aai
> > > Verzonden: dinsdag 28 april 2009 17:15
> > > Aan: Programming forum
> > > Onderwerp: Re: [Jprogramming] Levenshtein distance
> > >
> > > Here are IMO some optimizations:
> > >
> > > offsets for indices of neighbors advance :   B
> > > sentence for initial matrix C much shorter
> > > 'match' matrix of same size, in advance  :   M
> > > no boxing of indices
> > >
> > > levdist=: 3 : 0
> > > :
> > >   B=: 3 2$_1 0 0 _1 _1 _1
> > >   M=: 0,0,. x =/ y
> > >   C=: (ys=.i.>:#y),,.}.xs=.i.>:#x
> > >   stap"1 xs ,"0/&}. ys
> > >   {:, C
> > > )
> > >
> > > stap=: 3 : 0
> > >    u=. >: <./ (0 0,- M {~ <y) + C{~;/B +"1/ y
> > >    C=: u (<y)}C
> > > )
> > >
> > >
> > >    'excused' levdist 'exhausted'
> > > 3
> > >
> > >    'levenshtein' levdist 'malenstein'
> > > 4
> > >
> > >
> > >
> > >
> > > Hallo Jan Jacobs, je schreef op 28-04-09 11:42:
> > > > ls,
> > > > I modeled the edit-distance (or Levenshtein-distance
> > > > http://en.wikipedia.org/wiki/Levenshtein_distance) function for
> > > > strings, see below. I am not very proud of it. Hints for improvements
> > > > on elegancy
> > > > are welcomed (perhaps by using Sequential Machine ;:  ??).
> > > > Thanks in advance,
> > > > Jan.
> > > >
> > > > NB. Levenshtein
> > > > NB. y.      ~     word1
> > > > NB. x.      ~     word2
> > > > Levenshtein=:3 : 0
> > > > :
> > > >       ]C=:(i.>:#x)(<"1(0,.~xs=.i.>:#x))}
> > > > (ys=.i.>:#y)(0)}0$~>:(#X=:x),#Y=:y   NB. init
> > > >       ]ind=.,<"1 (}.xs),"0/ }.ys
> > > >                             NB. relevant indices
> > > >       step&.> ind
> > > >       {:{:"1 C
> > > > )
> > > > NB. make single step in C matrix
> > > > NB. y.      ~     current position
> > > > step=:3 : 0
> > > >       ]ins=.>:C{~<_1 0+y
> > > >       ]del=.>:C{~<0 _1+y
> > > >       ]nochxc=.(>:C{~<_1 _1+y)-(X{~<:{.y)=Y{~<:{:y
> > > >       ]C=:(<./ins,del,nochxc)(<y)}C
> > > > )
> > > > d=:1!:2&2
> > > > d 'asap'Levenshtein'aap'                        NB. 1
> > > > d 'excused'Levenshtein'exhausted'         NB. 3
> > > >
> > > >
> > > >
> > > > Jan Jacobs
> > > > Esdoornstraat 33
> > > > 5995AN Kessel
> > > > T: +31 77 462 1887
> > > > M: +31 6 23 82 55 21
> > > > E: [email protected]
> > > >
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> > >
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> > > =@@i
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-- 
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
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