On Wed, Oct 12, 2011 at 11:24 AM, I wrote:
> L=: 'label'
> D=: ,'p<label>0'8!:2 i.1e6
...
> F=:1 :0 NB. x: label, m: max labels to find, y: target
> :
> b=. 2*m*#x NB. block size to search (smaller for testing, larger
> for typical use)
> r=. i.0 NB. result
> for_block. |: b -~/\@(] <. [ * 0 1 +/i.@>.@%~) #y do.
> if. m-:#r do. return. end.
> 'z b'=. block
> r=. r, ({.~ (m-#r) <. #)z+x I.@E. y{~z+i.b
> end.
> )
Please note that this has a bug in it.
The problem is that it does not properly deal with the case where a
label straddles a block boundary.
The fix is to extend each block by (#label)-1 characters. For example
(untested code, sorry):
F=:1 :0 NB. x: label, m: max labels to find, y: target
:
b=. 2*m*#x NB. block size to search
r=. i.0 NB. result
ov=. 0, (#x)-1 NB. block overlap adjustment
for_block. |: b -~/\@(] <. ov + [ * 0 1 +/i.@>.@%~) #y do.
if. m-:#r do. return. end.
'z b'=. block
r=. r, ({.~ (m-#r) <. #)z+x I.@E. y{~z+i.b
end.
)
FYI,
--
Raul
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