Program f08mefe ! F08MEF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dbdsqr, f06qhf, nag_wp, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Real (Kind=nag_wp), Parameter :: one = 1.0_nag_wp Real (Kind=nag_wp), Parameter :: zero = 0.0_nag_wp Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: ifail, info, ldc, ldu, ldvt, n Character (1) :: uplo ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: c(:,:), d(:), e(:), u(:,:), vt(:,:), & work(:) ! .. Executable Statements .. Write (nout,*) 'F08MEF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n ldc = 1 ldu = n ldvt = n Allocate (c(ldc,1),d(n),e(n-1),u(ldu,n),vt(ldvt,n),work(4*n)) ! Read B from data file Read (nin,*) d(1:n) Read (nin,*) e(1:n-1) Read (nin,*) uplo ! Initialise U and VT to be the unit matrix Call f06qhf('General',n,n,zero,one,u,ldu) Call f06qhf('General',n,n,zero,one,vt,ldvt) ! Calculate the SVD of B ! The NAG name equivalent of dbdsqr is f08mef Call dbdsqr(uplo,n,n,n,0,d,e,vt,ldvt,u,ldu,c,ldc,work,info) Write (nout,*) If (info>0) Then Write (nout,*) 'Failure to converge.' Else ! Print singular values, left & right singular vectors Write (nout,*) 'Singular values' Write (nout,99999) d(1:n) Write (nout,*) Flush (nout) ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04caf('General',' ',n,n,vt,ldvt,'Right singular vectors, by row' & ,ifail) Write (nout,*) Flush (nout) ifail = 0 Call x04caf('General',' ',n,n,u,ldu,'Left singular vectors, by column' & ,ifail) End If 99999 Format (3X,(8F8.4)) End Program f08mefe