47 lines
1.7 KiB
Factor
47 lines
1.7 KiB
Factor
! :folding=indent:collapseFolds=0:
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! $Id$
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!
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! Copyright (C) 2004 Slava Pestov.
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!
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! Redistribution and use in source and binary forms, with or without
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! modification, are permitted provided that the following conditions are met:
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!
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! 1. Redistributions of source code must retain the above copyright notice,
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! this list of conditions and the following disclaimer.
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!
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! 2. Redistributions in binary form must reproduce the above copyright notice,
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! this list of conditions and the following disclaimer in the documentation
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! and/or other materials provided with the distribution.
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!
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! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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IN: quadratic
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USE: math
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USE: kernel
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: quadratic-e ( b a -- -b/2a )
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2 * / neg ;
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: quadratic-d ( a b c -- d )
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pick 4 * * swap sq swap - swap sq 4 * / sqrt ;
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: quadratic-roots ( d e -- alpha beta )
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2dup + -rot - ;
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: quadratic ( a b c -- alpha beta )
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#! Finds both roots of the polynomial a*x^2 + b*x + c
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#! using the quadratic formula.
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3dup quadratic-d
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nip swap rot quadratic-e
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swap quadratic-roots ;
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