28 lines
757 B
Factor
28 lines
757 B
Factor
! Copyright (c) 2008 Reginald Keith Ford II.
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel math math.function-tools math.points math.vectors ;
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IN: math.secant-method
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! Secant method of approximating roots
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<PRIVATE
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: secant-solution ( x1 x2 function -- solution )
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[ eval ] curry bi@ linear-solution ;
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: secant-step ( x1 x2 func -- x2 x3 func )
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[ secant-solution ] 2keep swapd ;
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: secant-precision ( -- n ) 15 ; inline
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PRIVATE>
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: secant-method ( left right function -- x )
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secant-precision [ secant-step ] times drop + 2 / ;
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! : close-enough? ( a b -- t/f ) - abs tiny-amount < ;
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! : secant-method2 ( left right function -- x )
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! 2over close-enough?
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! [ drop average ] [ secant-step secant-method ] if ;
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