Program f07hufe ! F07HUF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, x02ajf, zlanhb => f06uef, zpbcon, zpbtrf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=nag_wp) :: anorm, rcond Integer :: i, info, j, kd, ldab, n Character (1) :: uplo ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: ab(:,:), work(:) Real (Kind=nag_wp), Allocatable :: rwork(:) ! .. Intrinsic Procedures .. Intrinsic :: max, min ! .. Executable Statements .. Write (nout,*) 'F07HUF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n, kd ldab = kd + 1 Allocate (ab(ldab,n),work(2*n),rwork(n)) ! Read A 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 ! Compute norm of A ! f06uef is the NAG name equivalent of the LAPACK auxiliary zlanhb anorm = zlanhb('1-norm',uplo,n,kd,ab,ldab,rwork) ! Factorize A ! The NAG name equivalent of zpbtrf is f07hrf Call zpbtrf(uplo,n,kd,ab,ldab,info) Write (nout,*) If (info==0) Then ! Estimate condition number ! The NAG name equivalent of zpbcon is f07huf Call zpbcon(uplo,n,kd,ab,ldab,anorm,rcond,work,rwork,info) If (rcond>=x02ajf()) Then Write (nout,99999) 'Estimate of condition number =', & 1.0_nag_wp/rcond Else Write (nout,*) 'A is singular to working precision' End If Else Write (nout,*) 'A is not positive definite' End If 99999 Format (1X,A,1P,E10.2) End Program f07hufe