Program f02ecfe

!     F02ECF Example Program Text

!     Mark 28.3 Release. NAG Copyright 2022.

!     .. Use Statements ..
      Use nag_library, Only: f02ecf, nag_wp, x04dbf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: wl, wu
      Integer                          :: i, ifail, j, lda, ldv, ldvi, ldvr,   &
                                          lwork, m, mest, n
!     .. Local Arrays ..
      Complex (Kind=nag_wp), Allocatable :: v(:,:)
      Real (Kind=nag_wp), Allocatable  :: a(:,:), vi(:,:), vr(:,:), wi(:),     &
                                          work(:), wr(:)
      Integer, Allocatable             :: iwork(:)
      Logical, Allocatable             :: bwork(:)
      Character (1)                    :: clabs(1), rlabs(1)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: cmplx
!     .. Executable Statements ..
      Write (nout,*) 'F02ECF Example Program Results'
!     Skip heading in data file
      Read (nin,*)
      Read (nin,*) n, mest, wl, wu
      lda = n
      ldv = n
      ldvi = n
      ldvr = n
      lwork = 64*n
      Allocate (v(ldv,n),a(lda,n),vi(ldvi,mest),vr(ldvr,mest),wi(n),           &
        work(lwork),wr(n),iwork(n),bwork(n))

!     Read A from data file

      Read (nin,*)(a(i,1:n),i=1,n)

!     Compute selected eigenvalues and eigenvectors of A

!     ifail: behaviour on error exit
!            =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call f02ecf('Moduli',n,a,lda,wl,wu,mest,m,wr,wi,vr,ldvr,vi,ldvi,work,    &
        lwork,iwork,bwork,ifail)

      Write (nout,*)
      Write (nout,*) 'Eigenvalues'
      Write (nout,99999)(' (',wr(i),',',wi(i),')',i=1,m)
      Write (nout,*)
      Flush (nout)
      Do j = 1, m
        Do i = 1, n
          v(i,j) = cmplx(vr(i,j),vi(i,j),kind=nag_wp)
        End Do
      End Do

      ifail = 0
      Call x04dbf('General',' ',n,m,v,ldv,'Bracketed','F7.4','Eigenvectors',   &
        'Integer',rlabs,'Integer',clabs,80,0,ifail)

99999 Format ((3X,4(A,F7.4,A,F7.4,A,:)))
    End Program f02ecfe