[Fortran] syntaxhighlighter_viewsource syntaxhighlighter_copycode
rogram workfile
    Implicit none
    integer , parameter :: q = 1000
    real , parameter :: t1 = 3.12 , t2 = 0.29 , t3 = -0.0103
    complex , parameter :: i = (0, 1) , t0 = (0,0)
    real , parameter :: PI = acos(-1.0) , a0 = 1.42e-10
    real :: b1(2), b2(2) , a1(2) , a2(2) , m1 , m2
!    complex H(6, 6)
    real , allocatable :: k(:,:,:)
    complex :: f1 , f2
    integer :: x , y
! Output of the Hamiltonian matrix    
!    integer::i1
! Eigenvalue and Eigenvector of the Hamiltonian matrix
    CHARACTER JOBZ , UPLO
    integer :: INFO=0
    integer , parameter :: N=6, LDA=N ! , LWORK=3*N
    real*8 RWORK(3*N-2), W(N)
    complex*16 H(LDA,N), WORK(3*N)
    allocate(k(2,q-1,q-1))
    b1 = [ 2*PI/a0*sqrt(3.0) , 2*PI/a0 ]
    b2 = [ 2*PI/a0*sqrt(3.0) , -2*PI/a0 ]
    a1 = [ a0*sqrt(3.0)/2 , a0/2 ]
    a2 = [ a0*sqrt(3.0)/2 , -a0/2 ]
    Forall(x=1:size(k,2), y=1:size(k,3))
            k(:,x,y) = (b1*x+b2*y)/q
    End Forall
    m1 = dot_product(a1 , k(:,1,2))
    m2 = dot_product(a2 , k(:,1,2))
    f1 = 1+exp(i*m1)+exp(i*m2)
    f2 = 1+exp(-i*m1)+exp(-i*m2)
    H = reshape([complex::&
            t0, t1*f1, t0, t0, t0, t0,&
            t1*f2, t0, t0, t2, t0, t3,&
            t0, t0, t0, t1*f2, t0 ,t0,&
            t0, t2, t1*f1,t0, t0, t2, &
            t0, t0, t0, t0, t0, t1*f1,&
            t0, t3, t0, t0, t1*f2, t0],[6 , 6])
! Output of the Hamiltonian matrix
!    do i1=1,6
!        write(*,*)H(i1,:)
!    end do
!print *, H(:,:)
! Eigenvalue and eigenvector of the Hamiltonian matrix
call myzheev(N,W,H)
call ZHEEV('V', 'U', N, H(6,6), N, W, WORK, 3*N, RWORK, INFO)
print *,W
  contains
 subroutine myzheev(N,W,H)
    implicit none
    integer::N, INFO=0
    real*8::W(N),RWORK(3*N-2)
    complex*16::H(N,N),WORK(3*N)
    call ZHEEV('V', 'U', N, H, N, W, WORK, 3*N, RWORK, INFO)
  endsubroutine
End Program workfile