PROGRAM f07hdfe ! F07HDF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : dpbtrf, nag_wp, x04cef ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, ifail, info, j, kd, ldab, n CHARACTER (1) :: uplo ! .. Local Arrays .. REAL (KIND=nag_wp), ALLOCATABLE :: ab(:,:) ! .. Intrinsic Functions .. INTRINSIC max, min ! .. Executable Statements .. WRITE (nout,*) 'F07HDF Example Program Results' ! Skip heading in data file READ (nin,*) READ (nin,*) n, kd ldab = kd + 1 ALLOCATE (ab(ldab,n)) ! Read A from data file READ (nin,*) uplo IF (uplo=='U') THEN DO i = 1, n READ (nin,*) (ab(kd+1+i-j,j),j=i,min(n,i+kd)) END DO ELSE IF (uplo=='L') THEN DO i = 1, n READ (nin,*) (ab(1+i-j,j),j=max(1,i-kd),i) END DO END IF ! Factorize A ! The NAG name equivalent of dpbtrf is f07hdf CALL dpbtrf(uplo,n,kd,ab,ldab,info) WRITE (nout,*) FLUSH (nout) IF (info==0) THEN ! Print factor ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 IF (uplo=='U') THEN CALL x04cef(n,n,0,kd,ab,ldab,'Factor',ifail) ELSE IF (uplo=='L') THEN CALL x04cef(n,n,kd,0,ab,ldab,'Factor',ifail) END IF ELSE WRITE (nout,*) 'A is not positive definite' END IF END PROGRAM f07hdfe