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math.extras: Fix concentration-coefficient.

db4
Doug Coleman 2012-09-25 17:54:24 -07:00
parent d5e26ee76d
commit 1cf27a2af9
2 changed files with 10 additions and 1 deletions
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5
extra/math/extras/extras-tests.factor
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@ -60,3 +60,8 @@ IN: math.extras.test
{ 0 } [ { 1 1 1 1 1 1 } gini ] unit-test
{ 0 } [ { 10 10 10 10 } gini ] unit-test
{ 0 } [ { } gini ] unit-test
{ 0 } [ { 1 } concentration-coefficient ] unit-test
{ 0 } [ { 1 1 1 1 1 1 } concentration-coefficient ] unit-test
{ 0 } [ { 10 10 10 10 } concentration-coefficient ] unit-test
{ 0 } [ { } concentration-coefficient ] unit-test

6
extra/math/extras/extras.factor
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@ -172,4 +172,8 @@ PRIVATE>
dup length 1 <= [ drop 0 ] [ (gini) ] if ;
: concentration-coefficient ( seq -- x )
[ gini ] [ length [ ] [ 1 - ] bi / ] bi * ;
dup gini [
drop 0
] [
[ length [ ] [ 1 - ] bi / ] dip *
] if-zero ;