! :folding=indent:collapseFolds=0:

! $Id$
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! Copyright (C) 2004 Slava Pestov.
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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 ;