* F08XNF Example Program Text * Mark 21 Release. NAG Copyright 2004. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NB, NMAX PARAMETER (NB=64,NMAX=10) INTEGER LDA, LDB, LDVSL, LDVSR, LWORK PARAMETER (LDA=NMAX,LDB=NMAX,LDVSL=NMAX,LDVSR=NMAX, + LWORK=NMAX+NMAX*NB) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, LWKOPT, N, SDIM * .. Local Arrays .. COMPLEX *16 A(LDA,NMAX), ALPHA(NMAX), B(LDB,NMAX), + BETA(NMAX), VSL(LDVSL,NMAX), VSR(LDVSR,NMAX), + WORK(LWORK) DOUBLE PRECISION RWORK(8*NMAX) LOGICAL BWORK(NMAX) CHARACTER CLABS(1), RLABS(1) * .. External Functions .. LOGICAL F08XNZ EXTERNAL F08XNZ * .. External Subroutines .. EXTERNAL X04DBF, ZGGES * .. Intrinsic Functions .. INTRINSIC INT * .. Executable Statements .. WRITE (NOUT,*) 'F08XNF Example Program Results' WRITE (NOUT,*) * Skip heading in data file READ (NIN,*) READ (NIN,*) N IF (N.LE.NMAX) THEN * * Read in the matrices A and B * READ (NIN,*) ((A(I,J),J=1,N),I=1,N) READ (NIN,*) ((B(I,J),J=1,N),I=1,N) * * Find the generalized Schur form * 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.GT.0) THEN WRITE (NOUT,99999) 'Failure in ZGGES. INFO =', INFO ELSE * * Print out the factors of the generalized Schur factorization * 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,*) CALL X04DBF('General',' ',N,N,B,LDB,'Bracketed','F7.3', + 'Generalized Schur matrix T','Integer',RLABS, + 'Integer',CLABS,80,0,IFAIL) * WRITE (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,*) CALL X04DBF('General',' ',N,N,VSR,LDVSR,'Bracketed','F7.4', + 'Matrix of right generalized Schur vectors', + 'Integer',RLABS,'Integer',CLABS,80,0,IFAIL) * LWKOPT = INT(WORK(1)) IF (LWORK.LT.LWKOPT) THEN WRITE (NOUT,*) WRITE (NOUT,99998) 'Optimum workspace required = ', + LWKOPT, 'Workspace provided = ', LWORK END IF END IF ELSE WRITE (NOUT,*) WRITE (NOUT,*) 'NMAX too small' END IF * 99999 FORMAT (1X,A,I4) 99998 FORMAT (1X,A,I5,/1X,A,I5) END