38 lines
1.0 KiB
Factor
38 lines
1.0 KiB
Factor
! Copyright (C) 2004, 2005 Slava Pestov.
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! See http://factor.sf.net/license.txt for BSD license.
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IN: math
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USING: generic kernel kernel-internals math math-internals ;
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BUILTIN: ratio 4 [ 0 "numerator" f ] [ 1 "denominator" f ] ;
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UNION: rational integer ratio ;
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M: integer numerator ;
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M: integer denominator drop 1 ;
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IN: math-internals
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: 2>fraction ( a/b c/d -- a c b d )
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[ swap numerator swap numerator ] 2keep
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swap denominator swap denominator ; inline
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M: ratio number= ( a/b c/d -- ? )
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2>fraction number= [ number= ] [ 2drop f ] ifte ;
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: scale ( a/b c/d -- a*d b*c )
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2>fraction >r * swap r> * swap ;
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: ratio+d ( a/b c/d -- b*d )
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denominator swap denominator * ; inline
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M: ratio < scale < ;
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M: ratio <= scale <= ;
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M: ratio > scale > ;
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M: ratio >= scale >= ;
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M: ratio + ( x y -- x+y ) 2dup scale + -rot ratio+d integer/ ;
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M: ratio - ( x y -- x-y ) 2dup scale - -rot ratio+d integer/ ;
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M: ratio * ( x y -- x*y ) 2>fraction * >r * r> integer/ ;
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M: ratio / scale integer/ ;
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M: ratio /i scale /i ;
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M: ratio /f scale /f ;
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