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quantum_package/src/Utils/util.irp.f

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8.8 KiB
Fortran
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double precision function binom_func(i,j)
implicit none
BEGIN_DOC
!.. math ::
!
! \frac{i!}{j!(i-j)!}
!
END_DOC
integer,intent(in) :: i,j
double precision :: logfact
integer, save :: ifirst
double precision, save :: memo(0:15,0:15)
!DEC$ ATTRIBUTES ALIGN : $IRP_ALIGN :: memo
integer :: k,l
if (ifirst == 0) then
ifirst = 1
do k=0,15
do l=0,15
memo(k,l) = dexp( logfact(k)-logfact(l)-logfact(k-l) )
enddo
enddo
endif
if ( (i<=15).and.(j<=15) ) then
binom_func = memo(i,j)
else
binom_func = dexp( logfact(i)-logfact(j)-logfact(i-j) )
endif
end
BEGIN_PROVIDER [ double precision, binom, (0:40,0:40) ]
&BEGIN_PROVIDER [ double precision, binom_transp, (0:40,0:40) ]
implicit none
BEGIN_DOC
! Binomial coefficients
END_DOC
integer :: k,l
double precision :: logfact
do k=0,40
do l=0,40
binom(k,l) = dexp( logfact(k)-logfact(l)-logfact(k-l) )
binom_transp(l,k) = binom(k,l)
enddo
enddo
END_PROVIDER
integer function align_double(n)
implicit none
BEGIN_DOC
! Compute 1st dimension such that it is aligned for vectorization.
END_DOC
integer :: n
include 'constants.include.F'
if (mod(n,SIMD_vector/4) /= 0) then
align_double= n + SIMD_vector/4 - mod(n,SIMD_vector/4)
else
align_double= n
endif
end
double precision function fact(n)
implicit none
BEGIN_DOC
! n!
END_DOC
integer :: n
double precision, save :: memo(1:100)
integer, save :: memomax = 1
if (n<=memomax) then
if (n<2) then
fact = 1.d0
else
fact = memo(n)
endif
return
endif
integer :: i
memo(1) = 1.d0
do i=memomax+1,min(n,100)
memo(i) = memo(i-1)*dble(i)
enddo
memomax = min(n,100)
fact = memo(memomax)
do i=101,n
fact = fact*dble(i)
enddo
end function
double precision function logfact(n)
implicit none
BEGIN_DOC
! n!
END_DOC
integer :: n
double precision, save :: memo(1:100)
integer, save :: memomax = 1
if (n<=memomax) then
if (n<2) then
logfact = 0.d0
else
logfact = memo(n)
endif
return
endif
integer :: i
memo(1) = 0.d0
do i=memomax+1,min(n,100)
memo(i) = memo(i-1)+dlog(dble(i))
enddo
memomax = min(n,100)
logfact = memo(memomax)
do i=101,n
logfact += dlog(dble(i))
enddo
end function
BEGIN_PROVIDER [ double precision, fact_inv, (128) ]
implicit none
BEGIN_DOC
! 1/n!
END_DOC
integer :: i
double precision :: fact
do i=1,size(fact_inv)
fact_inv(i) = 1.d0/fact(i)
enddo
END_PROVIDER
double precision function dble_fact(n)
implicit none
integer :: n
double precision :: dble_fact_even, dble_fact_odd
dble_fact = 1.d0
if(n.lt.0) return
if(iand(n,1).eq.0)then
dble_fact = dble_fact_even(n)
else
dble_fact= dble_fact_odd(n)
endif
end function
double precision function dble_fact_even(n) result(fact2)
implicit none
BEGIN_DOC
! n!!
END_DOC
integer :: n,k
double precision, save :: memo(1:100)
integer, save :: memomax = 2
double precision :: prod
ASSERT (iand(n,1) /= 1)
prod=1.d0
do k=2,n,2
prod=prod*dfloat(k)
enddo
fact2=prod
return
end function
double precision function dble_fact_odd(n) result(fact2)
implicit none
BEGIN_DOC
! n!!
END_DOC
integer :: n
double precision, save :: memo(1:100)
integer, save :: memomax = 1
ASSERT (iand(n,1) /= 0)
if (n<=memomax) then
if (n<3) then
fact2 = 1.d0
else
fact2 = memo(n)
endif
return
endif
integer :: i
memo(1) = 1.d0
do i=memomax+2,min(n,99),2
memo(i) = memo(i-2)* dble(i)
enddo
memomax = min(n,99)
fact2 = memo(memomax)
if (n > 99) then
double precision :: dble_logfact
fact2 = dexp(dble_logfact(n))
endif
end function
double precision function dble_logfact(n) result(logfact2)
implicit none
BEGIN_DOC
! n!!
END_DOC
integer :: n
double precision, save :: memo(1:100)
integer, save :: memomax = 1
ASSERT (iand(n,1) /= 0)
if (n<=memomax) then
if (n<3) then
logfact2 = 0.d0
else
logfact2 = memo(n)
endif
return
endif
integer :: i
memo(1) = 0.d0
do i=memomax+2,min(n,99),2
memo(i) = memo(i-2)+ dlog(dble(i))
enddo
memomax = min(n,99)
logfact2 = memo(memomax)
do i=101,n,2
logfact2 += dlog(dble(i))
enddo
end function
subroutine write_git_log(iunit)
implicit none
BEGIN_DOC
! Write the last git commit in file iunit.
END_DOC
integer, intent(in) :: iunit
write(iunit,*) '----------------'
write(iunit,*) 'Last git commit:'
BEGIN_SHELL [ /bin/bash ]
git log -1 2>/dev/null | sed "s/'//g"| sed "s/^/ write(iunit,*) '/g" | sed "s/$/'/g" || echo "Unknown"
END_SHELL
write(iunit,*) '----------------'
end
BEGIN_PROVIDER [ double precision, inv_int, (128) ]
implicit none
BEGIN_DOC
! 1/i
END_DOC
integer :: i
do i=1,128
inv_int(i) = 1.d0/dble(i)
enddo
END_PROVIDER
subroutine wall_time(t)
implicit none
BEGIN_DOC
! The equivalent of cpu_time, but for the wall time.
END_DOC
double precision, intent(out) :: t
integer :: c
integer, save :: rate = 0
if (rate == 0) then
CALL SYSTEM_CLOCK(count_rate=rate)
endif
CALL SYSTEM_CLOCK(count=c)
t = dble(c)/dble(rate)
end
BEGIN_PROVIDER [ integer, nproc ]
implicit none
BEGIN_DOC
! Number of current OpenMP threads
END_DOC
integer :: omp_get_num_threads
nproc = 1
!$OMP PARALLEL
!$OMP MASTER
!$ nproc = omp_get_num_threads()
!$OMP END MASTER
!$OMP END PARALLEL
END_PROVIDER
BEGIN_PROVIDER [ integer, iproc_save, (nproc) ]
implicit none
BEGIN_DOC
! iproc_save(i) = i-1. Used to start threads with pthreads.
END_DOC
integer :: i
do i=1,nproc
iproc_save(i) = i-1
enddo
END_PROVIDER
double precision function u_dot_v(u,v,sze)
implicit none
BEGIN_DOC
! Compute <u|v>
END_DOC
integer, intent(in) :: sze
double precision, intent(in) :: u(sze),v(sze)
integer :: i,t1, t2, t3, t4
ASSERT (sze > 0)
t1 = 0
t2 = sze/4
t3 = t2+t2
t4 = t3+t2
u_dot_v = 0.d0
!DIR$ VECTOR ALWAYS
do i=1,t2
u_dot_v = u_dot_v + u(t1+i)*v(t1+i) + u(t2+i)*v(t2+i) + &
u(t3+i)*v(t3+i) + u(t4+i)*v(t4+i)
enddo
do i=t4+t2+1,sze
u_dot_v = u_dot_v + u(i)*v(i)
enddo
end
double precision function u_dot_u(u,sze)
implicit none
BEGIN_DOC
! Compute <u|u>
END_DOC
integer, intent(in) :: sze
double precision, intent(in) :: u(sze)
integer :: i
integer :: t1, t2, t3, t4
ASSERT (sze > 0)
t1 = 0
t2 = sze/4
t3 = t2+t2
t4 = t3+t2
u_dot_u = 0.d0
! do i=1,t2
! u_dot_u = u_dot_u + u(t1+i)*u(t1+i) + u(t2+i)*u(t2+i) + &
! u(t3+i)*u(t3+i) + u(t4+i)*u(t4+i)
! enddo
! do i=t4+t2+1,sze
! u_dot_u = u_dot_u+u(i)*u(i)
! enddo
!DIR$ VECTOR ALWAYS
do i=1,sze
u_dot_u = u_dot_u + u(i)*u(i)
enddo
end
subroutine normalize(u,sze)
implicit none
BEGIN_DOC
! Normalizes vector u
! u is expected to be aligned in memory.
END_DOC
integer, intent(in) :: sze
double precision, intent(inout):: u(sze)
double precision :: d
double precision, external :: u_dot_u
integer :: i
!DIR$ FORCEINLINE
d = u_dot_u(u,sze)
if (d /= 0.d0) then
d = 1.d0/dsqrt( d )
endif
if (d /= 1.d0) then
do i=1,sze
u(i) = d*u(i)
enddo
endif
end
double precision function approx_dble(a,n)
implicit none
integer, intent(in) :: n
double precision, intent(in) :: a
double precision :: f
integer :: i
if (a == 0.d0) then
approx_dble = 0.d0
return
endif
f = 1.d0
do i=1,-int(dlog10(dabs(a)))+n
f = f*.1d0
enddo
do i=1,int(dlog10(dabs(a)))-n
f = f*10.d0
enddo
approx_dble = dnint(a/f)*f
end
subroutine lowercase(txt,n)
implicit none
BEGIN_DOC
! Transform to lower case
END_DOC
character*(*), intent(inout) :: txt
integer, intent(in) :: n
character( * ), PARAMETER :: LOWER_CASE = 'abcdefghijklmnopqrstuvwxyz'
character( * ), PARAMETER :: UPPER_CASE = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
integer :: i, ic
do i=1,n
ic = index( UPPER_CASE, txt(i:i) )
if (ic /= 0) then
txt(i:i) = LOWER_CASE(ic:ic)
endif
enddo
end
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