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https://github.com/QuantumPackage/qp2.git
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206 lines
4.7 KiB
Fortran
206 lines
4.7 KiB
Fortran
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double precision function SABpartial(zA,zB,A,B,nA,nB,gamA,gamB,l)
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implicit double precision(a-h,o-z)
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dimension nA(3),nB(3)
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dimension A(3),B(3)
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gamtot=gamA+gamB
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SABpartial=1.d0
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u=gamA/gamtot*A(l)+gamB/gamtot*B(l)
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arg=gamtot*u**2-gamA*A(l)**2-gamB*B(l)**2
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alpha=dexp(arg)
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&/gamtot**((1.d0+dfloat(nA(l))+dfloat(nB(l)))/2.d0)
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wA=dsqrt(gamtot)*(u-A(l))
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wB=dsqrt(gamtot)*(u-B(l))
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boundA=dsqrt(gamtot)*(zA-u)
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boundB=dsqrt(gamtot)*(zB-u)
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accu=0.d0
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do n=0,nA(l)
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do m=0,nB(l)
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integ=nA(l)+nB(l)-n-m
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accu=accu
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& +wA**n*wB**m*binom(nA(l),n)*binom(nB(l),m)
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& *(rinteg(integ,boundB)-rinteg(integ,boundA))
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enddo
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enddo
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SABpartial=SABpartial*accu*alpha
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end
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double precision function rintgauss(n)
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implicit double precision(a-h,o-z)
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rintgauss=dsqrt(dacos(-1.d0))
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if(n.eq.0)return
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if(n.eq.1)then
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rintgauss=0.d0
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return
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endif
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if(iand(n,1).eq.1)then
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rintgauss=0.d0
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return
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endif
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rintgauss=rintgauss/2.d0**(n/2)
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rintgauss=rintgauss*ddfact2(n-1)
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end
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double precision function rinteg(n,u)
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implicit double precision(a-h,o-z)
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include 'constants.include.F'
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ichange=1
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factor=1.d0
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if(u.lt.0.d0)then
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u=-u
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factor=(-1.d0)**(n+1)
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ichange=-1
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endif
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if(iand(n,1).eq.0)then
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rinteg=0.d0
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do l=0,n-2,2
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prod=b_coef(l,u)
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do k=l+2,n-2,2
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prod=prod*a_coef(k)
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enddo
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rinteg=rinteg+prod
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enddo
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prod=dsqrt(pi)/2.d0*erf0(u)
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do k=0,n-2,2
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prod=prod*a_coef(k)
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enddo
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rinteg=rinteg+prod
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endif
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if(iand(n,1).eq.1)then
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rinteg=0.d0
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do l=1,n-2,2
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prod=b_coef(l,u)
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do k=l+2,n-2,2
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prod=prod*a_coef(k)
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enddo
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rinteg=rinteg+prod
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enddo
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prod=0.5d0*(1.d0-dexp(-u**2))
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do k=1,n-2,2
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prod=prod*a_coef(k)
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enddo
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rinteg=rinteg+prod
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endif
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rinteg=rinteg*factor
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if(ichange.eq.-1)u=-u
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end
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double precision function erf0(x)
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implicit double precision (a-h,o-z)
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if(x.lt.0.d0)then
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erf0=-gammp(0.5d0,x**2)
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else
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erf0=gammp(0.5d0,x**2)
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endif
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end
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double precision function gammp(a,x)
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implicit double precision (a-h,o-z)
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if(x.lt.0..or.a.le.0.)stop 'error in gammp'
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if(x.lt.a+1.)then
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call gser(gammp,a,x,gln)
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else
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call gcf(gammcf,a,x,gln)
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gammp=1.-gammcf
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endif
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return
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end
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subroutine gser(gamser,a,x,gln)
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implicit double precision (a-h,o-z)
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parameter (itmax=100,eps=3.e-7)
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gln=gammln(a)
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if(x.le.0.)then
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if(x.lt.0.) stop 'error in gser'
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gamser=0.
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return
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endif
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ap=a
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sum=1./a
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del=sum
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do 11 n=1,itmax
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ap=ap+1.
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del=del*x/ap
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sum=sum+del
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if(abs(del).lt.abs(sum)*eps)go to 1
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11 continue
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stop 'a too large, itmax too small'
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1 gamser=sum*exp(-x+a*log(x)-gln)
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return
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end
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subroutine gcf(gammcf,a,x,gln)
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implicit double precision (a-h,o-z)
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parameter (itmax=100,eps=3.e-7)
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gln=gammln(a)
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gold=0.
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a0=1.
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a1=x
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b0=0.
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b1=1.
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fac=1.
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do 11 n=1,itmax
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an=float(n)
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ana=an-a
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a0=(a1+a0*ana)*fac
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b0=(b1+b0*ana)*fac
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anf=an*fac
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a1=x*a0+anf*a1
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b1=x*b0+anf*b1
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if(a1.ne.0.)then
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fac=1./a1
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g=b1*fac
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if(abs((g-gold)/g).lt.eps)go to 1
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gold=g
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endif
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11 continue
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stop 'a too large, itmax too small'
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1 gammcf=exp(-x+a*log(x)-gln)*g
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return
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end
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double precision function ddfact2(n)
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implicit double precision(a-h,o-z)
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if(iand(n,1).eq.0)stop 'error in ddfact2'
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ddfact2=1.d0
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do i=1,n,2
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ddfact2=ddfact2*dfloat(i)
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enddo
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end
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double precision function a_coef(n)
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implicit double precision(a-h,o-z)
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a_coef=dfloat(n+1)/2.d0
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end
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double precision function b_coef(n,u)
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implicit double precision(a-h,o-z)
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b_coef=-0.5d0*u**(n+1)*dexp(-u**2)
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end
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double precision function gammln(xx)
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implicit double precision (a-h,o-z)
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real*8 cof(6),stp,half,one,fpf,x,tmp,ser
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data cof,stp/76.18009173d0,-86.50532033d0,24.01409822d0,
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* -1.231739516d0,.120858003d-2,-.536382d-5,2.50662827465d0/
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data half,one,fpf/0.5d0,1.0d0,5.5d0/
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x=xx-one
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tmp=x+fpf
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tmp=(x+half)*log(tmp)-tmp
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ser=one
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do 11 j=1,6
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x=x+one
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ser=ser+cof(j)/x
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11 continue
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gammln=tmp+log(stp*ser)
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return
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end
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