Program f02wufe
! F02WUF Example Program Text
! Mark 30.2 Release. NAG Copyright 2024.
! .. Use Statements ..
Use nag_library, Only: f02wuf, nag_wp, x04cbf
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
! .. Local Scalars ..
Integer :: i, ifail, lda, ldb, ldq, lwork, n, &
ncolb
Logical :: wantp, wantq
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: a(:,:), b(:), q(:,:), sv(:), work(:)
Character (1) :: clabs(1), rlabs(1)
! .. Executable Statements ..
Write (nout,*) 'F02WUF Example Program Results'
Write (nout,*)
! Skip heading in data file
Read (nin,*)
Read (nin,*) n, ncolb
lda = n
ldb = n
ldq = n
lwork = 5*(n-1)
Allocate (a(lda,n),b(ldb),q(ldq,n),sv(n),work(lwork))
Read (nin,*)(a(i,i:n),i=1,n)
Read (nin,*) b(1:n)
wantq = .True.
wantp = .True.
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
! Find the SVD of A
Call f02wuf(n,a,lda,ncolb,b,ldb,wantq,q,ldq,sv,wantp,work,ifail)
Write (nout,*) 'Singular value decomposition of A'
Write (nout,*)
Write (nout,*) 'Singular values'
Write (nout,99999) sv(1:n)
Write (nout,*)
Flush (nout)
ifail = 0
Call x04cbf('General',' ',n,n,q,ldq,'F8.4', &
'Left-hand singular vectors, by column','N',rlabs,'N',clabs,80,0, &
ifail)
Write (nout,*)
Write (nout,*) 'Right-hand singular vectors, by column'
Do i = 1, n
Write (nout,99999) a(1:n,i)
End Do
Write (nout,*)
Write (nout,*) 'Vector Q''*B'
Write (nout,99999) b(1:n)
99999 Format (1X,3(1X,F8.4))
End Program f02wufe