factor/library/math/pow.factor

! :folding=indent:collapseFolds=0:

! $Id$
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! Copyright (C) 2004 Slava Pestov.
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IN: math
USE: arithmetic
USE: combinators
USE: real-math
USE: kernel
USE: stack

! Power-related functions:
!     exp log sqrt pow

: exp >rect swap fexp swap polar> ;
: log >polar swap flog swap rect> ;

: sqrt ( z -- sqrt )
    >polar dup pi = [
        drop fsqrt 0 swap rect>
    ] [
        swap fsqrt swap 2 / polar>
    ] ifte ;

: ^mag ( w abs arg -- magnitude )
    [ [ >rect swap ] dip swap fpow ] dip rot * fexp / ;

: ^theta ( w abs arg -- theta )
    [ [ >rect ] dip flog * swap ] dip * + ;

: ^ ( z w -- z^w )
    swap >polar 3dup ^theta [ ^mag ] dip polar> ;