NAG Library Manual, Mark 30
Interfaces:  FL   CL   CPP   AD 

NAG FL Interface Introduction
Example description
    Program f01blfe

!     F01BLF Example Program Text

!     Mark 30.0 Release. NAG Copyright 2024.

!     .. Use Statements ..
      Use nag_library, Only: f01blf, f06raf, nag_wp, x02ajf, x04cbf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: indent = 0, ncols = 80, nin = 5,     &
                                          nout = 6
      Character (1), Parameter         :: diag = 'N', matrix = 'G',            &
                                          nolabel = 'N'
      Character (8), Parameter         :: form = '1P,E12.4'
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: anorm, t
      Integer                          :: i, ifail, irank, lda, ldu, m, n
      Character (9)                    :: norm
      Character (27)                   :: title
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: a(:,:), aijmax(:), d(:), du(:),      &
                                          u(:,:)
      Real (Kind=nag_wp)               :: work(1)
      Integer, Allocatable             :: inc(:)
      Character (1)                    :: dummy(1)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: min
!     .. Executable Statements ..
      Write (nout,*) 'F01BLF Example Program Results'
      Write (nout,*)
!     Skip heading in data file
      Read (nin,*)
      Read (nin,*) m, n
      lda = m
      ldu = n
      Allocate (a(lda,n),aijmax(n),d(m),du(n),u(ldu,n),inc(n))
      Read (nin,*)(a(i,1:n),i=1,m)
!     Set t = eps times norm of A.
      norm = 'Frobenius'
      anorm = f06raf(norm,m,n,a,lda,work)
      t = anorm*x02ajf()

!     ifail: behaviour on error exit
!             =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
      ifail = 0
      Call f01blf(m,n,t,a,lda,aijmax,irank,inc,d,u,ldu,du,ifail)

      Write (nout,*) 'Maximum element in A(K) for I.GE.K and J.GE.K'
      Write (nout,*)
      Write (nout,*) '   K    Modulus'
      Write (nout,99999)(i,aijmax(i),i=1,min(n,irank+1))
      Write (nout,*)
      Write (nout,99998) 'Rank = ', irank
      Write (nout,*)
      Write (nout,99997) 'T = ', t, '  (machine dependent)'
      Write (nout,*)
      Flush (nout)
!     Print the result matrix A.
      title = 'Transpose of pseudo-inverse'
      ifail = 0
      Call x04cbf(matrix,diag,m,n,a,lda,form,title,nolabel,dummy,nolabel,      &
        dummy,ncols,indent,ifail)

99999 Format (1X,I4,2X,1P,E12.4)
99998 Format (1X,A,I5)
99997 Format (1X,A,1P,E11.4,A)
    End Program f01blfe