* F08NSF Example Program Text * Mark 16 Release. NAG Copyright 1992. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, LDA, LWORK PARAMETER (NMAX=8,LDA=NMAX,LWORK=64*NMAX) COMPLEX *16 ZERO PARAMETER (ZERO=(0.0D0,0.0D0)) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, N * .. Local Arrays .. COMPLEX *16 A(LDA,NMAX), TAU(NMAX-1), WORK(LWORK) CHARACTER CLABS(1), RLABS(1) * .. External Subroutines .. EXTERNAL X04DBF, ZGEHRD * .. Executable Statements .. WRITE (NOUT,*) 'F08NSF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N IF (N.LE.NMAX) THEN * * Read A from data file * READ (NIN,*) ((A(I,J),J=1,N),I=1,N) * * Reduce A to upper Hessenberg form * CALL ZGEHRD(N,1,N,A,LDA,TAU,WORK,LWORK,INFO) * * Set the elements below the first sub-diagonal to zero * DO 40 I = 1, N - 2 DO 20 J = I + 2, N A(J,I) = ZERO 20 CONTINUE 40 CONTINUE * * Print upper Hessenberg form * WRITE (NOUT,*) IFAIL = 0 * CALL X04DBF('General',' ',N,N,A,LDA,'Bracketed','F7.4', + 'Upper Hessenberg form','Integer',RLABS,'Integer', + CLABS,80,0,IFAIL) * END IF STOP END