Program f07hefe ! F07HEF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dpbtrf, dpbtrs, nag_wp, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, info, j, kd, ldab, ldb, n, & nrhs Character (1) :: uplo ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: ab(:,:), b(:,:) ! .. Intrinsic Procedures .. Intrinsic :: max, min ! .. Executable Statements .. Write (nout,*) 'F07HEF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n, kd, nrhs ldab = kd + 1 ldb = n Allocate (ab(ldab,n),b(ldb,nrhs)) ! Read A and B 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 Read (nin,*)(b(i,1:nrhs),i=1,n) ! 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 ! Compute solution ! The NAG name equivalent of dpbtrs is f07hef Call dpbtrs(uplo,n,kd,nrhs,ab,ldab,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 f07hefe