Program f07wjfe ! F07WJF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dpftrf, dpftri, dtfttr, nag_wp, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: ifail, info, ldf, lena, n Character (1) :: transr, uplo ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: a(:), f(:,:) ! .. Executable Statements .. Write (nout,*) 'F07WJF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n, uplo, transr lena = n*(n+1)/2 ldf = n Allocate (a(lena),f(ldf,n)) ! Read A from data file Read (nin,*) a(1:lena) ! Factorize A ! The NAG name equivalent of dpftrf is f07wdf Call dpftrf(transr,uplo,n,a,info) Write (nout,*) Flush (nout) If (info==0) Then ! Compute inverse of A ! The NAG name equivalent of dpftri is f07wjf Call dpftri(transr,uplo,n,a,info) ! Convert inverse to full array form, and print it ! The NAG name equivalent of dtfttr is f01vgf Call dtfttr(transr,uplo,n,a,f,ldf,info) ifail = 0 Call x04caf(uplo,'Nonunit',n,n,f,ldf,'Inverse',ifail) Else Write (nout,*) 'A is not positive definite' End If End Program f07wjfe