Program f07fwfe ! F07FWF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, x04dbf, zpotrf, zpotri ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, info, lda, n Character (1) :: uplo ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: a(:,:) Character (1) :: clabs(1), rlabs(1) ! .. Executable Statements .. Write (nout,*) 'F07FWF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n lda = n Allocate (a(lda,n)) ! Read A from data file Read (nin,*) uplo If (uplo=='U') Then Read (nin,*)(a(i,i:n),i=1,n) Else If (uplo=='L') Then Read (nin,*)(a(i,1:i),i=1,n) End If ! Factorize A ! The NAG name equivalent of zpotrf is f07frf Call zpotrf(uplo,n,a,lda,info) Write (nout,*) Flush (nout) If (info==0) Then ! Compute inverse of A ! The NAG name equivalent of zpotri is f07fwf Call zpotri(uplo,n,a,lda,info) ! Print inverse ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04dbf(uplo,'Nonunit',n,n,a,lda,'Bracketed','F7.4','Inverse', & 'Integer',rlabs,'Integer',clabs,80,0,ifail) Else Write (nout,*) 'A is not positive definite' End If End Program f07fwfe