factor/library/math/math.factor

! :folding=indent:collapseFolds=0:

! $Id$
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! Copyright (C) 2004 Slava Pestov.
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IN: math
USE: kernel
USE: math
USE: math-internals

: fac ( n -- n! )
    ! This is the naive implementation, for benchmarking purposes.
    1 swap [ succ * ] times* ;

: mag2 ( x y -- mag )
    #! Returns the magnitude of the vector (x,y).
    swap sq swap sq + fsqrt ;

: abs ( z -- abs )
    #! Compute the complex absolute value.
    dup complex? [ >rect mag2 ] [ dup 0 < [ neg ] when ] ifte ;

: conjugate ( z -- z* )
    >rect neg rect> ;

: arg ( z -- arg )
    #! Compute the complex argument.
    >rect swap fatan2 ; inline

: >polar ( z -- abs arg )
    >rect 2dup swap fatan2 >r mag2 r> ;

: cis ( theta -- cis )
    dup fcos swap fsin rect> ;

: polar> ( abs arg -- z )
    cis * ; inline

: align ( offset width -- offset )
    2dup mod dup 0 = [ 2drop ] [ - + ] ifte ;