Adding math-compare vocabulary.

extra/math/compare/authors.txt

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+John Benediktsson

extra/math/compare/compare-docs.factor

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+! Copyright (C) 2008 John Benediktsson
+! See http://factorcode.org/license.txt for BSD license
+
+USING: help.markup help.syntax ;
+
+IN: math.compare
+
+HELP: absmin
+{ $values { "a" "a number" } { "b" "a number" } { "x" "a number" } }
+{ $description 
+    "Returns the smaller absolute number with the original sign." 
+} ;
+
+HELP: absmax
+{ $values { "a" "a number" } { "b" "a number" } { "x" "a number" } }
+{ $description 
+    "Returns the larger absolute number with the original sign."
+} ;
+
+HELP: posmax
+{ $values { "a" "a number" } { "b" "a number" } { "x" "a number" } }
+{ $description 
+    "Returns the most-positive value, or zero if both are negative."
+} ;
+
+HELP: negmin
+{ $values { "a" "a number" } { "b" "a number" } { "x" "a number" } }
+{ $description 
+    "Returns the most-negative value, or zero if both are positive."
+} ;
+
+HELP: clamp
+{ $values { "a" "a number" } { "value" "a number" } { "b" "a number" } { "x" "a number" } }
+{ $description 
+    "Returns the value when between 'a' and 'b', 'a' if <= 'a', or 'b' if >= 'b'."
+} ;
+

extra/math/compare/compare-tests.factor

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+USING: kernel math math.functions math.compare tools.test ;
+
+IN: math.compare.tests
+
+[ -1 ] [ -1 5 absmin ] unit-test
+[ -1 ] [ -1 -5 absmin ] unit-test
+
+[ -5 ] [ 1 -5 absmax ] unit-test
+[ 5 ] [ 1 5 absmax ] unit-test
+
+[ 0 ] [ -1 -3 posmax ] unit-test
+[ 1 ] [ 1 -3 posmax ] unit-test
+[ 3 ] [ -1 3 posmax ] unit-test
+
+[ 0 ] [ 1 3 negmin ] unit-test
+[ -3 ] [ 1 -3 negmin ] unit-test
+[ -1 ] [ -1 3 negmin ] unit-test
+
+[ 0 ] [ 0 -1 2 clamp ] unit-test
+[ 1 ] [ 0 1 2 clamp ] unit-test
+[ 2 ] [ 0 3 2 clamp ] unit-test
+
+
+
+

extra/math/compare/compare.factor

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+USING: math math.order kernel ;
+
+IN: math.compare 
+
+: absmin ( a b -- x ) 
+   [ [ abs ] dip abs < ] 2keep ? ;
+
+: absmax ( a b -- x ) 
+   [ [ abs ] dip abs > ] 2keep ? ;
+
+: posmax ( a b -- x ) 
+   0 max max ;
+
+: negmin ( a b -- x ) 
+   0 min min ;
+
+: clamp ( a value b -- x )
+   min max ; 
+

extra/math/compare/summary.txt

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+Comparison functions.