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math.statistics: adding demean and demedian, cleanup a bit.

db4
John Benediktsson 2013-03-28 11:40:46 -07:00
parent c403857f0d
commit 02d9565732
2 changed files with 13 additions and 12 deletions
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23
basis/math/statistics/statistics.factor
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@ -288,9 +288,13 @@ ALIAS: std sample-std
: signal-to-noise ( seq -- x ) [ mean ] [ population-std ] bi / ;
: mean-dev ( seq -- x ) dup mean v-n vabs mean ;
: demean ( seq -- seq' ) dup mean v-n ;
: median-dev ( seq -- x ) dup median v-n vabs mean ;
: mean-dev ( seq -- x ) demean vabs mean ;
: demedian ( seq -- seq' ) dup median v-n ;
: median-dev ( seq -- x ) demedian vabs mean ;
: ste-ddof ( seq n -- x ) '[ _ std-ddof ] [ length ] bi sqrt / ;
@ -322,7 +326,7 @@ ALIAS: std sample-std
[ swapd * - ] keep ;
: cov-ddof ( {x} {y} ddof -- cov )
[ [ dup mean v-n ] bi@ v* ] dip mean-ddof ;
[ [ demean ] bi@ v* ] dip mean-ddof ;
: population-cov ( {x} {y} -- cov ) 0 cov-ddof ; inline
@ -349,8 +353,7 @@ ALIAS: std sample-std
1 [ * ] cum-map ;
: cum-count ( seq quot -- seq' )
[ 0 ] dip
'[ _ call [ 1 + ] when ] cum-map ; inline
[ 0 ] dip '[ _ call [ 1 + ] when ] cum-map ; inline
: cum-min ( seq -- seq' )
dup ?first [ min ] cum-map ;
@ -371,15 +374,13 @@ ALIAS: std sample-std
[ dup log * ] [ 1 swap - dup log * ] bi + neg 2 log / ;
: standardize ( u -- v )
[ dup mean v-n ] [ sample-std ] bi
dup zero? [ drop ] [ v/n ] if ;
[ demean ] [ sample-std ] bi [ v/n ] unless-zero ;
: standardize-2d ( u -- v )
flip dup [ [ mean ] [ sample-std ] bi 2array ] map
[ [ first v-n ] 2map ] keep [ second v/n ] 2map flip ;
flip [ standardize ] map flip ;
: differences ( u -- v )
[ 1 tail-slice ] keep [ - ] 2map ;
[ 1 tail-slice ] keep v- ;
: rescale ( u -- v )
dup minmax over - [ v-n ] [ v/n ] bi* ;
@ -393,4 +394,4 @@ ALIAS: std sample-std
[ '[ first2 [ _ set-nth ] with each ] each ] keep ;
: z-score ( seq -- n )
dup [ mean ] [ sample-std ] bi '[ _ - _ / ] map ;
[ demean ] [ sample-std ] bi v/n ;

2
extra/math/distances/distances.factor
View File

@ -31,4 +31,4 @@ IN: math.distances
[ v- ] [ v+ ] 2bi [ vabs sum ] bi@ / ;
: correlation-distance ( a b -- n )
[ dup mean v-n ] bi@ [ v* sum ] [ [ norm ] bi@ * ] 2bi / 1 swap - ;
[ demean ] bi@ [ v* sum ] [ [ norm ] bi@ * ] 2bi / 1 swap - ;