Program f08kjfe ! F08KJF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: ddisna, dgesvj, nag_wp, x02ajf, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=nag_wp) :: eps, serrbd Integer :: i, ifail, info, j, lda, ldv, lwork, & m, n ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: a(:,:), rcondu(:), rcondv(:), s(:), & v(:,:), work(:) ! .. Intrinsic Procedures .. Intrinsic :: abs ! .. Executable Statements .. Write (nout,*) 'F08KJF Example Program Results' Write (nout,*) Flush (nout) ! Skip heading in data file Read (nin,*) Read (nin,*) m, n lda = m ldv = n lwork = n + m Allocate (a(lda,n),rcondu(m),rcondv(m),s(n),v(ldv,n),work(lwork)) ! Read the m by n matrix A from data file Read (nin,*)((a(i,j),j=1,n),i=1,m) ! Compute the singular values and left and right singular vectors ! of A (A = U*S*V, m.ge.n) ! The NAG name equivalent of dgesvj is f08kjf Call dgesvj('G','U','V',m,n,a,lda,s,0,v,ldv,work,lwork,info) If (info==0) Then ! Compute the approximate error bound for the computed singular values ! using the 2-norm, s(1) = norm(A), and machine precision, eps. eps = x02ajf() serrbd = eps*s(1) ! Print solution Write (nout,*) 'Singular values' Write (nout,99999)(s(j),j=1,n) If (abs(work(1)-1.0_nag_wp)>eps) Then Write (nout,99996) 'Values need scaling by factor = ', work(1) End If Flush (nout) ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04caf('General',' ',m,n,a,lda,'Left singular vectors',ifail) Write (nout,*) Flush (nout) ifail = 0 Call x04caf('General',' ',n,n,v,ldv,'Right singular vectors',ifail) ! Call DDISNA (F08FLF) to estimate reciprocal condition ! numbers for the singular vectors Call ddisna('Left',m,n,s,rcondu,info) Call ddisna('Right',m,n,s,rcondv,info) ! Print the approximate error bounds for the singular values ! and vectors Write (nout,'(/1X,A)') 'Error estimate for the singular values' Write (nout,99998) serrbd Write (nout,'(/1X,A)') 'Error estimates for left singular vectors' Write (nout,99998)(serrbd/rcondu(i),i=1,n) Write (nout,'(/1X,A)') 'Error estimates for right singular vectors' Write (nout,99998)(serrbd/rcondv(i),i=1,n) Else Write (nout,99997) 'Failure in DGESVJ. INFO =', info End If 99999 Format (3X,(8F8.4)) 99998 Format (4X,1P,6E11.1) 99997 Format (1X,A,I4) 99996 Format (/1X,A,1P,E13.5) End Program f08kjfe