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math.combinatorics: minor performance improvements.

db4
John Benediktsson 2012-04-24 18:42:34 -07:00
parent fc50417e43
commit 817b45ee03
2 changed files with 5 additions and 5 deletions
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8
basis/math/combinatorics/combinatorics.factor
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@ -32,13 +32,13 @@ PRIVATE>
<PRIVATE <PRIVATE
: factoradic ( n -- factoradic ) : factoradic ( n -- factoradic )
0 [ over 0 > ] [ 1 + [ /mod ] keep swap ] produce reverse 2nip ; 0 [ over 0 > ] [ 1 + [ /mod ] keep swap ] produce reverse! 2nip ;
: (>permutation) ( seq n -- seq ) : (>permutation) ( seq n -- seq )
[ '[ _ dupd >= [ 1 + ] when ] map ] keep prefix ; [ '[ _ dupd >= [ 1 + ] when ] map! ] keep prefix ;
: >permutation ( factoradic -- permutation ) : >permutation ( factoradic -- permutation )
reverse 1 cut [ (>permutation) ] each ; reverse! 1 cut [ (>permutation) ] each ;
: permutation-indices ( n seq -- permutation ) : permutation-indices ( n seq -- permutation )
length [ factoradic ] dip 0 pad-head >permutation ; length [ factoradic ] dip 0 pad-head >permutation ;
@ -147,7 +147,7 @@ C: <combo> combo
:: combination-indices ( m combo -- seq ) :: combination-indices ( m combo -- seq )
combo m combo dual-index combinadic combo m combo dual-index combinadic
combo seq>> length 1 - swap [ - ] with map ; combo seq>> length 1 - swap [ - ] with map! ;
: apply-combination ( m combo -- seq ) : apply-combination ( m combo -- seq )
[ combination-indices ] keep seq>> nths ; [ combination-indices ] keep seq>> nths ;

2
extra/project-euler/common/common.factor
View File

@ -80,7 +80,7 @@ PRIVATE>
] if ; ] if ;
: number>digits ( n -- seq ) : number>digits ( n -- seq )
[ dup 0 = not ] [ 10 /mod ] produce reverse nip ; [ dup 0 = not ] [ 10 /mod ] produce reverse! nip ;
: number-length ( n -- m ) : number-length ( n -- m )
abs [ abs [