PROGRAM f07ajfe ! F07AJF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : dgetrf, dgetri, nag_wp, x04caf ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, ifail, info, lda, lwork, n ! .. Local Arrays .. REAL (KIND=nag_wp), ALLOCATABLE :: a(:,:), work(:) INTEGER, ALLOCATABLE :: ipiv(:) ! .. Executable Statements .. WRITE (nout,*) 'F07AJF Example Program Results' ! Skip heading in data file READ (nin,*) READ (nin,*) n lda = n lwork = 64*n ALLOCATE (a(lda,n),work(lwork),ipiv(n)) ! Read A from data file READ (nin,*) (a(i,1:n),i=1,n) ! Factorize A ! The NAG name equivalent of dgetrf is f07adf CALL dgetrf(n,n,a,lda,ipiv,info) WRITE (nout,*) FLUSH (nout) IF (info==0) THEN ! Compute inverse of A ! The NAG name equivalent of dgetri is f07ajf CALL dgetri(n,a,lda,ipiv,work,lwork,info) ! Print inverse ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL x04caf('General',' ',n,n,a,lda,'Inverse',ifail) ELSE WRITE (nout,*) 'The factor U is singular' END IF END PROGRAM f07ajfe