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  • Committer: Bazaar Package Importer
  • Author(s): Torsten Werner
  • Date: 2002-03-21 16:57:43 UTC
  • Revision ID: james.westby@ubuntu.com-20020321165743-e9mv12c1tb1plztg
Tags: upstream-2.6
Import upstream version 2.6

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routines/calelm/wdpowe.f
 
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      subroutine wdpowe(vr,vi,p,rr,ri,ierr)
 
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c!purpose
 
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c     computes v^p with v complex and p real
 
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c!calling sequence 
 
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c     subroutine wdpowe(vr,vi,p,rr,ri,ierr)
 
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c     integer ierr
 
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c     double precision vr,vi,p,rr,ri
 
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c     vr   : real part of v
 
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c     vi   : imaginary part of v
 
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c     rr   : result's real part
 
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c     ri   : result's imaginary part
 
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c     ierr : error flag
 
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c            ierr=0 if ok
 
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c            ierr=1 if 0**0
 
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c            ierr=2 if  0**k with k<0
 
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c!origin
 
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c Serge Steer INRIA 1996
 
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c!
 
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c     Copyright INRIA
 
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      integer ierr
 
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      double precision vr,vi,p,sr,si,rr,ri
 
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c
 
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      ierr=0
 
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c
 
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      if(dble(int(p)).eq.p) then 
 
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         call wipowe(vr,vi,int(p),rr,ri,ierr)
 
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      else
 
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         if(abs(vr)+abs(vi).ne.0.0d+0) then
 
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            call wlog(vr,vi,sr,si)
 
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            sr=exp(sr*p)
 
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            si=si*p
 
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            rr=sr*cos(si)
 
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            ri=sr*sin(si)
 
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         else
 
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            if(p.gt.0.0d+0) then
 
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               rr=0.0d+0
 
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               ri=0.0d+0
 
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            elseif(p.lt.0.0d+0) then
 
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               ri=0.0d+0
 
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               rr=infinity(ri)
 
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               ierr=2
 
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            else
 
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               rr=1.0d+0
 
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               ri=0.0d+0
 
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            endif
 
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         endif
 
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      endif
 
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c     
 
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      return
 
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      end