Program f08atfe ! F08ATF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, x04dbf, zgeqrf, zungqr ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, info, lda, lwork, m, n Character (30) :: title ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: a(:,:), tau(:), work(:) Character (1) :: clabs(1), rlabs(1) ! .. Executable Statements .. Write (nout,*) 'F08ATF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) m, n lda = m lwork = 64*n Allocate (a(lda,n),tau(n),work(lwork)) ! Read A from data file Read (nin,*)(a(i,1:n),i=1,m) ! Compute the QR factorization of A ! The NAG name equivalent of zgeqrf is f08asf Call zgeqrf(m,n,a,lda,tau,work,lwork,info) ! Form the leading N columns of Q explicitly ! The NAG name equivalent of zungqr is f08atf Call zungqr(m,n,n,a,lda,tau,work,lwork,info) ! Print the leading N columns of Q only Write (nout,*) Write (title,99999) n Flush (nout) ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04dbf('General',' ',m,n,a,lda,'Bracketed','F7.4',title,'Integer', & rlabs,'Integer',clabs,80,0,ifail) 99999 Format ('The leading ',I2,' columns of Q') End Program f08atfe