PROGRAM f08xnfe ! F08XNF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : f08xnz, nag_wp, x04dbf, zgges ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nb = 64, nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, ifail, info, lda, ldb, ldvsl, & ldvsr, lwork, n, sdim ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: a(:,:), alpha(:), b(:,:), & beta(:), vsl(:,:), vsr(:,:), & work(:) COMPLEX (KIND=nag_wp) :: dummy(1) REAL (KIND=nag_wp), ALLOCATABLE :: rwork(:) LOGICAL, ALLOCATABLE :: bwork(:) CHARACTER (1) :: clabs(1), rlabs(1) ! .. Intrinsic Functions .. INTRINSIC max, nint, real ! .. Executable Statements .. WRITE (nout,*) 'F08XNF Example Program Results' WRITE (nout,*) FLUSH (nout) ! Skip heading in data file READ (nin,*) READ (nin,*) n lda = n ldb = n ldvsl = n ldvsr = n ALLOCATE (a(lda,n),alpha(n),b(ldb,n),beta(n),vsl(ldvsl,n),vsr(ldvsr,n), & rwork(8*n),bwork(n)) ! Use routine workspace query to get optimal workspace. lwork = -1 ! The NAG name equivalent of zgges is f08xnf CALL zgges('Vectors (left)','Vectors (right)','No sort',f08xnz,n,a,lda, & b,ldb,sdim,alpha,beta,vsl,ldvsl,vsr,ldvsr,dummy,lwork,rwork,bwork, & info) ! Make sure that there is enough workspace for blocksize nb. lwork = max((nb+1)*n,nint(real(dummy(1)))) ALLOCATE (work(lwork)) ! Read in the matrices A and B READ (nin,*) (a(i,1:n),i=1,n) READ (nin,*) (b(i,1:n),i=1,n) ! Find the generalized Schur form ! The NAG name equivalent of zgges is f08xnf CALL zgges('Vectors (left)','Vectors (right)','No sort',f08xnz,n,a,lda, & b,ldb,sdim,alpha,beta,vsl,ldvsl,vsr,ldvsr,work,lwork,rwork,bwork, & info) IF (info>0) THEN WRITE (nout,99999) 'Failure in ZGGES. INFO =', info ELSE ! Print out the factors of the generalized Schur factorization ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL x04dbf('General',' ',n,n,a,lda,'Bracketed','F7.3', & 'Generalized Schur matrix S','Integer',rlabs,'Integer',clabs,80, & 0,ifail) WRITE (nout,*) FLUSH (nout) CALL x04dbf('General',' ',n,n,b,ldb,'Bracketed','F7.3', & 'Generalized Schur matrix T','Integer',rlabs,'Integer',clabs,80, & 0,ifail) WRITE (nout,*) FLUSH (nout) CALL x04dbf('General',' ',n,n,vsl,ldvsl,'Bracketed','F7.4', & 'Matrix of left generalized Schur vectors','Integer',rlabs, & 'Integer',clabs,80,0,ifail) WRITE (nout,*) FLUSH (nout) CALL x04dbf('General',' ',n,n,vsr,ldvsr,'Bracketed','F7.4', & 'Matrix of right generalized Schur vectors','Integer',rlabs, & 'Integer',clabs,80,0,ifail) END IF 99999 FORMAT (1X,A,I4) END PROGRAM f08xnfe