factor/examples/quadratic.factor

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1.7 KiB
Factor

! :folding=indent:collapseFolds=0:
! $Id$
!
! Copyright (C) 2004 Slava Pestov.
!
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! modification, are permitted provided that the following conditions are met:
!
! 1. Redistributions of source code must retain the above copyright notice,
! this list of conditions and the following disclaimer.
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! 2. Redistributions in binary form must reproduce the above copyright notice,
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! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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IN: quadratic
USE: math
USE: kernel
: quadratic-e ( b a -- -b/2a )
2 * / neg ;
: quadratic-d ( a b c -- d )
pick 4 * * swap sq swap - swap sq 4 * / sqrt ;
: quadratic-roots ( d e -- alpha beta )
2dup + -rot - ;
: quadratic ( a b c -- alpha beta )
#! Finds both roots of the polynomial a*x^2 + b*x + c
#! using the quadratic formula.
3dup quadratic-d
nip swap rot quadratic-e
swap quadratic-roots ;