Program f08krfe ! F08KRF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, zgesdd ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nb = 64, nin = 5, nout = 6, & prerr = 0 ! .. Local Scalars .. Integer :: i, info, lda, ldu, ldvt, & lwork, m, n ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: a(:,:), a_copy(:,:), b(:), & u(:,:), vt(:,:), work(:) Complex (Kind=nag_wp) :: dummy(1,1) Real (Kind=nag_wp), Allocatable :: rwork(:), s(:) Integer, Allocatable :: iwork(:) ! .. Intrinsic Procedures .. Intrinsic :: max, min, nint, real ! .. Executable Statements .. Continue Write (nout,*) 'F08KRF Example Program Results' Write (nout,*) ! Skip heading in data file Read (nin,*) Read (nin,*) m, n lda = m ldu = m ldvt = n Allocate (a(lda,n),a_copy(m,n),s(m),u(ldu,m),vt(ldvt,n),b(m),rwork((5*m+ & 7)*n),iwork(8*m)) ! Read the m by n matrix A from data file Read (nin,*)(a(i,1:n),i=1,m) ! Read the right hand side of the linear system Read (nin,*) b(1:m) a_copy(1:m,1:n) = a(1:m,1:n) ! Use routine workspace query to get optimal workspace. lwork = -1 ! The NAG name equivalent of dgesdd is f08krf Call zgesdd('A',m,n,a,lda,s,u,ldu,vt,ldvt,dummy,lwork,rwork,iwork,info) ! Make sure that there is enough workspace for blocksize nb. lwork = max((2*m+2)*m+2*n+nb*(m+n),nint(real(dummy(1,1)))) Allocate (work(lwork)) ! Compute the singular values and left and right singular vectors ! of A. ! The NAG name equivalent of dgesdd is f08krf Call zgesdd('A',m,n,a,lda,s,u,ldu,vt,ldvt,work,lwork,rwork,iwork,info) If (info/=0) Then Write (nout,99999) 'Failure in F08KRF/ZGESDD. INFO =', info 99999 Format (1X,A,I4) Go To 100 End If ! Print the significant singular values of A Write (nout,*) 'Singular values of A:' Write (nout,99998) s(1:min(m,n)) 99998 Format (1X,4(3X,F11.4)) If (prerr>0) Then Call compute_error_bounds(m,n,s) End If If (m