Program f03bnfe

!     F03BNF Example Program Text

!     Mark 27.3 Release. NAG Copyright 2021.

!     .. Use Statements ..
      Use nag_library, Only: f03bnf, nag_wp, x04daf, zgetrf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Real (Kind=nag_wp), Parameter    :: two = 2.0_nag_wp
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Complex (Kind=nag_wp)            :: d
      Integer                          :: i, ifail, info, lda, n
!     .. Local Arrays ..
      Complex (Kind=nag_wp), Allocatable :: a(:,:)
      Integer                          :: id(2)
      Integer, Allocatable             :: ipiv(:)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: aimag, real
!     .. Executable Statements ..
      Write (nout,*) 'F03BNF Example Program Results'

!     Skip heading in data file
      Read (nin,*)

      Read (nin,*) n
      lda = n
      Allocate (a(lda,n),ipiv(n))

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

!     LU Factorize A
!     The NAG name equivalent of zgetrf is f07arf
      Call zgetrf(n,n,a,lda,ipiv,info)
      Write (nout,*)
      Flush (nout)

      ifail = 0
      Call x04daf('g','n',n,n,a,lda,'Array A after factorization',ifail)

      Write (nout,*)
      Write (nout,*) 'Pivots'
      Write (nout,99999) ipiv(1:n)
      Write (nout,*)
      Flush (nout)

      ifail = 0
      Call f03bnf(n,a,lda,ipiv,d,id,ifail)

      Write (nout,99998) d, id
      Write (nout,*)
      Write (nout,99997) two**id(1)*real(d), two**id(2)*aimag(d)

99999 Format (1X,8(1X,I13))
99998 Format (1X,'D = (',F13.5,',',F13.5,'), ID = (',I0,', ',I0,')')
99997 Format (1X,'Value of determinant = (',E13.5,',',E13.5,')')
    End Program f03bnfe