PROGRAM f08anfe ! F08ANF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : dznrm2, nag_wp, zgels ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nb = 64, nin = 5, nout = 6 ! .. Local Scalars .. REAL (KIND=nag_wp) :: rnorm INTEGER :: i, info, lda, lwork, m, n ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: a(:,:), b(:), work(:) ! .. Executable Statements .. WRITE (nout,*) 'F08ANF Example Program Results' WRITE (nout,*) ! Skip heading in data file READ (nin,*) READ (nin,*) m, n lda = m lwork = n + nb*m ALLOCATE (a(lda,n),b(m),work(lwork)) ! Read A and B from data file READ (nin,*) (a(i,1:n),i=1,m) READ (nin,*) b(1:m) ! Solve the least squares problem min( norm2(b - Ax) ) for x ! The NAG name equivalent of zgels is f08anf CALL zgels('No transpose',m,n,1,a,lda,b,m,work,lwork,info) ! Print solution WRITE (nout,*) 'Least squares solution' WRITE (nout,99999) b(1:n) ! Compute and print estimate of the square root of the residual ! sum of squares ! The NAG name equivalent of dznrm2 is f06jjf rnorm = dznrm2(m-n,b(n+1),1) WRITE (nout,*) WRITE (nout,*) 'Square root of the residual sum of squares' WRITE (nout,99998) rnorm 99999 FORMAT (4(' (',F7.4,',',F7.4,')':)) 99998 FORMAT (1X,1P,E10.2) END PROGRAM f08anfe