Program f03bhfe ! F03BHF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dpbtrf, f03bhf, nag_wp, x04cef ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=nag_wp) :: d Integer :: i, id, ifail, info, j, kd, kl, ku, & ldab, n Character (1) :: uplo ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: ab(:,:) ! .. Intrinsic Procedures .. Intrinsic :: index, max, min ! .. Executable Statements .. Write (nout,*) 'F03BHF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) uplo Read (nin,*) n, kd ldab = kd + 1 Allocate (ab(ldab,n)) If (index('Ll',uplo)<=0) Then ! Read in upper triangular banded matrix ku = kd kl = 0 Do i = 1, n Read (nin,*)(ab(kd+1+i-j,j),j=i,min(i+kd,n)) End Do Else ! Read in lower triangular banded matrix ku = 0 kl = kd Do i = 1, n Read (nin,*)(ab(1+i-j,j),j=max(1,i-kd),i) End Do End If ! Factorize A ! The NAG name equivalent of dpbtrf is f07hdf Call dpbtrf(uplo,n,kd,ab,ldab,info) If (info==0) Then Write (nout,*) Flush (nout) ifail = 0 Call x04cef(n,n,kl,ku,ab,ldab,'Array AB after factorization',ifail) ifail = 0 Call f03bhf(uplo,n,kd,ab,ldab,d,id,ifail) Write (nout,*) Write (nout,99999) d, id Write (nout,*) Write (nout,99998) d*2.0E0_nag_wp**id Else Write (nout,99997) info End If 99999 Format (1X,'D = ',F13.5,' ID = ',I0) 99998 Format (1X,'Value of determinant = ',E13.5) 99997 Format (' ** Factorization routine return error flag info = ',I0,'.') End Program f03bhfe