PROGRAM f08atfe ! F08ATF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. 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