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Viewing changes to vendor/IREGI/src/qcdloop/ql/qlLi2omprod.f

  • Committer: Marco Zaro
  • Date: 2014-01-27 16:54:10 UTC
  • mfrom: (78.124.55 MG5_aMC_2.1)
  • Revision ID: marco.zaro@gmail.com-20140127165410-5lma8c2hzbzm426j
merged with lp:~maddevelopers/madgraph5/MG5_aMC_2.1 r 267

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vendor/IREGI/src/qcdloop/ql/qlLi2omprod.f
 
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      double complex function qlLi2omprod(v,w,z,iep)
 
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      implicit none
 
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      include 'qlconstants.f'
 
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c     expression for dilog(1-(v-i*ep)/(w-i*ep)*(z+iep)) 
 
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C     for real v,w and complex z
 
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      double precision v,w,y,ddilog,rarg,omrarg,iep
 
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      double complex qllnrat,lnarg,lnomarg,prod,arg,omarg,z,cln,
 
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     . denspence
 
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      if (abs(dimag(z)) .lt. 1d-15) then
 
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C----case for real z
 
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      y=dreal(z)
 
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      rarg=v*y/w
 
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      omrarg=1d0-rarg
 
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      if (rarg .le. 1d0) then
 
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         if (rarg .eq. 0d0 .or. rarg .eq. 1d0) then 
 
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            prod=0d0
 
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         else
 
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            lnarg=qllnrat(v,w)+cln(z,iep)
 
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            lnomarg=dcmplx(log(omrarg))
 
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            prod=lnarg*lnomarg
 
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         endif
 
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         qlLi2omprod=dcmplx(pisqo6-ddilog(rarg))-prod
 
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      elseif (rarg .gt. 1d0) then
 
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         rarg=w/(y*v)
 
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         lnarg=-qllnrat(v,w)-cln(z,iep)
 
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         lnomarg=dcmplx(log(1d0-rarg))
 
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         qlLi2omprod=-dcmplx(pisqo6-ddilog(rarg))+lnarg*lnomarg
 
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     .   -0.5d0*lnarg**2
 
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      endif
 
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      else
 
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C----case for complex z
 
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      arg=dcmplx(v/w)*z
 
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      omarg=cone-arg
 
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      if (abs(arg) .le. 1d0) then
 
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         if (abs(arg) .eq. 0d0 .or. abs(arg) .eq. 1d0) then 
 
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            prod=0d0
 
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         else
 
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            lnarg=qllnrat(v,w)+cln(z,iep)
 
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            lnomarg=log(omarg)
 
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            prod=lnarg*lnomarg
 
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         endif
 
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         qlLi2omprod=dcmplx(pisqo6)-denspence(arg,1d0)-prod
 
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      elseif (abs(arg) .gt. 1d0) then
 
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         arg=w/(z*v)
 
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         lnarg=-qllnrat(v,w)-cln(z,iep)
 
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         lnomarg=log(cone-arg)
 
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         qlLi2omprod=-dcmplx(pisqo6)+denspence(arg,1d0)+lnarg*lnomarg
 
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     .   -0.5d0*lnarg**2
 
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      endif
 
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      endif
 
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      return 
 
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      end