math.statistics: fix typo

[factor.git] / basis / math / statistics / statistics.factor

diff --git a/basis/math/statistics/statistics.factor b/basis/math/statistics/statistics.factor
index 4950dd983cb5750762c7634cc8155274f719f1ac..ab5e10a6e6aa5ac359725f038790b2c9600a573f 100644 (file)
--- a/basis/math/statistics/statistics.factor
+++ b/basis/math/statistics/statistics.factor
@@ -1,7 +1,8 @@
 ! Copyright (C) 2008 Doug Coleman, Michael Judge, Loryn Jenkins.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: arrays assocs combinators fry generalizations grouping
-kernel locals math math.functions math.order math.vectors
+USING: accessors arrays assocs combinators
+combinators.short-circuit fry generalizations grouping kernel
+locals math math.functions math.order ranges math.vectors
 sequences sequences.private sorting ;
 IN: math.statistics
 
@@ -16,8 +17,45 @@ IN: math.statistics
 : mean ( seq -- x )
     0 mean-ddof ; inline
 
-: sum-of-squares ( seq -- x )
-    [ sq ] map-sum ; inline
+: meanest ( seq -- x )
+    [ mean ] keep [ - abs ] with infimum-by ;
+
+GENERIC: sum-of-squares ( seq -- x )
+M: object sum-of-squares [ sq ] map-sum ;
+M: iota sum-of-squares
+    n>> 1 - [ ] [ 1 + ] [ 1/2 + ] tri * * 3 / ;
+M: ranges:range sum-of-squares
+    dup { [ step>> 1 = ] [ from>> integer? ] } 1&& [
+        [ from>> ] [ length>> ] bi dupd +
+        [ <iota> sum-of-squares ] bi@ swap -
+    ] [ call-next-method ] if ;
+
+GENERIC: sum-of-cubes ( seq -- x )
+M: object sum-of-cubes [ 3 ^ ] map-sum ;
+M: iota sum-of-cubes sum sq ;
+M: ranges:range sum-of-cubes
+    dup { [ step>> 1 = ] [ from>> integer? ] } 1&& [
+        [ from>> ] [ length>> ] bi dupd +
+        [ <iota> sum-of-cubes ] bi@ swap -
+    ] [ call-next-method ] if ;
+
+GENERIC: sum-of-quads ( seq -- x )
+M: object sum-of-quads [ 4 ^ ] map-sum ;
+M: iota sum-of-quads
+    [let n>> 1 - :> n
+        n 0 > [
+            n
+            n 1 +
+            n 2 * 1 +
+            n sq 3 * n 3 * + 1 -
+            * * * 30 /
+        ] [ 0 ] if
+    ] ;
+M: ranges:range sum-of-quads
+    dup { [ step>> 1 = ] [ from>> integer? ] } 1&& [
+        [ from>> ] [ length>> ] bi dupd +
+        [ <iota> sum-of-quads ] bi@ swap -
+    ] [ call-next-method ] if ;
 
 : sum-of-squared-errors ( seq -- x )
     [ mean ] keep [ - sq ] with map-sum ; inline
@@ -86,7 +124,7 @@ PRIVATE>
     k seq nth-unsafe ; inline
 
 : (kth-object) ( seq k nth-quot exchange-quot quot: ( x y -- ? ) -- elt )
-    ! The algorithm modifiers seq, so we clone it
+    ! The algorithm modifies seq, so we clone it
     [ >array ] 4dip kth-object-impl ; inline
 
 : kth-object-unsafe ( seq k quot: ( x y -- ? ) -- elt )
@@ -213,11 +251,14 @@ PRIVATE>
 : trimean ( seq -- x )
     quartile first3 [ 2 * ] dip + + 4 / ;
 
+: histogram-by! ( assoc seq quot: ( x -- bin ) -- hashtable )
+    rot [ '[ @ _ inc-at ] each ] keep ; inline
+
 : histogram! ( hashtable seq -- hashtable )
-    over '[ _ inc-at ] each ;
+    [ ] histogram-by! ; inline
 
 : histogram-by ( seq quot: ( x -- bin ) -- hashtable )
-    H{ } clone [ '[ @ _ inc-at ] each ] keep ; inline
+    [ H{ } clone ] 2dip histogram-by! ; inline
 
 : histogram ( seq -- hashtable )
     [ ] histogram-by ;
@@ -370,3 +411,15 @@ PRIVATE>
 
 : z-score ( seq -- n )
     [ demean ] [ sample-std ] bi v/n ;
+
+: dcg ( scores -- dcg )
+    dup length 1 + 2 swap [a..b] [ log 2 log /f ] map v/ sum ;
+
+: ndcg ( scores -- ndcg )
+    [ 0.0 ] [
+        dup dcg [
+            drop 0.0
+        ] [
+            swap natural-sort <reversed> dcg /f
+        ] if-zero
+    ] if-empty ;