Program f08npfe ! F08NPF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: nag_wp, x02ajf, zgeevx ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nb = 64, nin = 5, nout = 6 ! .. Local Scalars .. Real (Kind=nag_wp) :: abnrm, eps, tol Integer :: i, ihi, ilo, info, j, lda, ldvl, & ldvr, lwork, n ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: a(:,:), vl(:,:), vr(:,:), w(:), & work(:) Complex (Kind=nag_wp) :: dummy(1) Real (Kind=nag_wp), Allocatable :: rconde(:), rcondv(:), rwork(:), & scale(:) ! .. Intrinsic Procedures .. Intrinsic :: max, nint, real ! .. Executable Statements .. Write (nout,*) 'F08NPF Example Program Results' ! Skip heading in data file Read (nin,*) Read (nin,*) n lda = n ldvl = n ldvr = n Allocate (a(lda,n),vl(ldvl,n),vr(ldvr,n),w(n),rconde(n),rcondv(n), & rwork(2*n),scale(n)) ! Use routine workspace query to get optimal workspace. lwork = -1 ! The NAG name equivalent of zgeevx is f08npf Call zgeevx('Balance','Vectors (left)','Vectors (right)', & 'Both reciprocal condition numbers',n,a,lda,w,vl,ldvl,vr,ldvr,ilo,ihi, & scale,abnrm,rconde,rcondv,dummy,lwork,rwork,info) ! Make sure that there is enough workspace for blocksize nb. lwork = max((nb+1)*n,nint(real(dummy(1)))) Allocate (work(lwork)) ! Read the matrix A from data file Read (nin,*)(a(i,1:n),i=1,n) ! Solve the eigenvalue problem ! The NAG name equivalent of zgeevx is f08npf Call zgeevx('Balance','Vectors (left)','Vectors (right)', & 'Both reciprocal condition numbers',n,a,lda,w,vl,ldvl,vr,ldvr,ilo,ihi, & scale,abnrm,rconde,rcondv,work,lwork,rwork,info) If (info==0) Then ! Compute the machine precision eps = x02ajf() tol = eps*abnrm ! Print the eigenvalues and vectors, and associated condition ! number and bounds Write (nout,*) Write (nout,*) 'Eigenvalues' Write (nout,*) Write (nout,*) ' Eigenvalue rcond error' Do j = 1, n ! Print information on jth eigenvalue If (rconde(j)>0.0_nag_wp) Then If (tol/rconde(j)<10.0_nag_wp*eps) Then Write (nout,99999) j, w(j), rconde(j), '-' Else Write (nout,99998) j, w(j), rconde(j), tol/rconde(j) End If Else Write (nout,99999) j, w(j), rconde(j), 'Inf' End If End Do Write (nout,*) Write (nout,*) 'Eigenvectors' Write (nout,*) Write (nout,*) ' Eigenvector rcond error' Do j = 1, n ! Print information on jth eigenvector Write (nout,*) ! Make first real part component be positive If (real(vr(1,j))<0.0_nag_wp) Then vr(1:n,j) = -vr(1:n,j) End If If (rcondv(j)>0.0_nag_wp) Then If (tol/rcondv(j)<10.0_nag_wp*eps) Then Write (nout,99999) j, vr(1,j), rcondv(j), '-' Else Write (nout,99998) j, vr(1,j), rcondv(j), tol/rcondv(j) End If Else Write (nout,99999) j, vr(1,j), rcondv(j), 'Inf' End If Write (nout,99997) vr(2:n,j) End Do Write (nout,*) Write (nout,*) 'Errors below 10*machine precision are not displayed' Else Write (nout,*) Write (nout,99996) 'Failure in ZGEEVX. INFO =', info End If 99999 Format (1X,I2,1X,'(',1P,E11.4,',',E11.4,')',1X,0P,F7.4,4X,A) 99998 Format (1X,I2,1X,'(',1P,E11.4,',',E11.4,')',1X,0P,F7.4,1X,1P,E8.1) 99997 Format (1X,3X,'(',1P,E11.4,',',E11.4,')') 99996 Format (1X,A,I4) End Program f08npfe