Program f08qffe ! F08QFF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dtrexc, nag_wp, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, ifst, ilst, info, ldq, & ldt, n ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: q(:,:), t(:,:), work(:) ! .. Executable Statements .. Write (nout,*) 'F08QFF Example Program Results' Write (nout,*) Flush (nout) ! Skip heading in data file Read (nin,*) Read (nin,*) n ldq = 1 ldt = n Allocate (q(ldq,1),t(ldt,n),work(n)) ! Read T from data file Read (nin,*)(t(i,1:n),i=1,n) ! Read the row indices Read (nin,*) ifst, ilst ! Reorder the Schur factor T ! The NAG name equivalent of dtrexc is f08qff Call dtrexc('No update',n,t,ldt,q,ldq,ifst,ilst,work,info) If (info>0) Then Write (nout,99999) info, ilst Write (nout,*) Flush (nout) End If ! Print reordered Schur factor ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04caf('General',' ',n,n,t,ldt,'Reordered Schur form',ifail) 99999 Format (' Reordering could not be completed. INFO = ',I3,' ILST = ',I5) End Program f08qffe