PROGRAM f07fefe ! F07FEF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : dpotrf, dpotrs, nag_wp, x04caf ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, ifail, info, lda, ldb, n, nrhs CHARACTER (1) :: uplo ! .. Local Arrays .. REAL (KIND=nag_wp), ALLOCATABLE :: a(:,:), b(:,:) ! .. Executable Statements .. WRITE (nout,*) 'F07FEF Example Program Results' ! Skip heading in data file READ (nin,*) READ (nin,*) n, nrhs lda = n ldb = n ALLOCATE (a(lda,n),b(ldb,nrhs)) ! Read A and B from data file READ (nin,*) uplo IF (uplo=='U') THEN READ (nin,*) (a(i,i:n),i=1,n) ELSE IF (uplo=='L') THEN READ (nin,*) (a(i,1:i),i=1,n) END IF READ (nin,*) (b(i,1:nrhs),i=1,n) ! Factorize A ! The NAG name equivalent of dpotrf is f07fdf CALL dpotrf(uplo,n,a,lda,info) WRITE (nout,*) FLUSH (nout) IF (info==0) THEN ! Compute solution ! The NAG name equivalent of dpotrs is f07fef CALL dpotrs(uplo,n,nrhs,a,lda,b,ldb,info) ! Print solution ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL x04caf('General',' ',n,nrhs,b,ldb,'Solution(s)',ifail) ELSE WRITE (nout,*) 'A is not positive definite' END IF END PROGRAM f07fefe