Program f07bsfe ! F07BSF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, x04dbf, zgbtrf, zgbtrs ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 Character (1), Parameter :: trans = 'N' ! .. Local Scalars .. Integer :: i, ifail, info, j, k, kl, ku, ldab, & ldb, n, nrhs ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: ab(:,:), b(:,:) Integer, Allocatable :: ipiv(:) Character (1) :: clabs(1), rlabs(1) ! .. Intrinsic Procedures .. Intrinsic :: max, min ! .. Executable Statements .. Write (nout,*) 'F07BSF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n, nrhs, kl, ku ldab = 2*kl + ku + 1 ldb = n Allocate (ab(ldab,n),b(ldb,nrhs),ipiv(n)) ! Read A and B from data file k = kl + ku + 1 Read (nin,*)((ab(k+i-j,j),j=max(i-kl,1),min(i+ku,n)),i=1,n) Read (nin,*)(b(i,1:nrhs),i=1,n) ! Factorize A ! The NAG name equivalent of zgbtrf is f07brf Call zgbtrf(n,n,kl,ku,ab,ldab,ipiv,info) Write (nout,*) Flush (nout) If (info==0) Then ! Compute solution ! The NAG name equivalent of zgbtrs is f07bsf Call zgbtrs(trans,n,kl,ku,nrhs,ab,ldab,ipiv,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 x04dbf('General',' ',n,nrhs,b,ldb,'Bracketed','F7.4', & 'Solution(s)','Integer',rlabs,'Integer',clabs,80,0,ifail) Else Write (nout,*) 'The factor U is singular' End If End Program f07bsfe