PROGRAM f07fcfe ! F07FCF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : dsposv, nag_rp, nag_wp ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, info, iter, lda, ldb, ldx, n, r ! .. Local Arrays .. REAL (KIND=nag_wp), ALLOCATABLE :: a(:,:), b(:,:), work(:,:), x(:,:) REAL (KIND=nag_rp), ALLOCATABLE :: swork(:) ! .. Executable Statements .. WRITE (nout,*) 'F07FCF Example Program Results' WRITE (nout,*) ! Skip heading in data file READ (nin,*) READ (nin,*) n, r lda = n ldb = n ldx = n ALLOCATE (a(lda,n),b(n,r),work(n,r),x(ldx,r),swork(n*(n+r))) ! Read the upper triangular part of A from data file READ (nin,*) (a(i,i:n),i=1,n) ! Read B from data file READ (nin,*) (b(i,1:r),i=1,n) ! Solve the equations Ax = b for x ! The NAG name equivalent of dsposv is f07fcf CALL dsposv('U',n,r,a,lda,b,ldb,x,ldx,work,swork,iter,info) IF (info==0) THEN ! Print solution WRITE (nout,*) 'Solution' WRITE (nout,99999) (x(i,1:r),i=1,n) ELSE WRITE (nout,99998) 'The leading minor of order ', info, & ' is not positive definite' END IF 99999 FORMAT ((3X,7F11.4)) 99998 FORMAT ((1X,A,I3,A)) END PROGRAM f07fcfe