PROGRAM f07vsfe ! F07VSF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : nag_wp, x04dbf, ztbtrs ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 CHARACTER (1), PARAMETER :: diag = 'N', trans = 'N' ! .. Local Scalars .. INTEGER :: i, ifail, info, j, kd, ldab, ldb, n, & nrhs CHARACTER (1) :: uplo ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: ab(:,:), b(:,:) CHARACTER (1) :: clabs(1), rlabs(1) ! .. Intrinsic Functions .. INTRINSIC max, min ! .. Executable Statements .. WRITE (nout,*) 'F07VSF 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) ! Compute solution ! The NAG name equivalent of ztbtrs is f07vsf CALL ztbtrs(uplo,trans,diag,n,kd,nrhs,ab,ldab,b,ldb,info) ! Print solution WRITE (nout,*) FLUSH (nout) IF (info==0) THEN ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL x04dbf('General',' ',n,nrhs,b,ldb,'Bracketed','F7.4', & 'Solution(s)','Integer',rlabs,'Integer',clabs,80,0,ifail) ELSE WRITE (nout,*) 'A is singular' END IF END PROGRAM f07vsfe