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mirror of https://github.com/QuantumPackage/qp2.git synced 2024-11-06 13:33:37 +01:00
qp2/src/utils/need.irp.f
2019-01-25 11:39:31 +01:00

206 lines
4.7 KiB
Fortran

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