* F08JCF Example Program Text * Mark 20 Revised. NAG Copyright 2001. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, LDZ PARAMETER (NMAX=8,LDZ=NMAX) INTEGER LWORK, LIWORK PARAMETER (LWORK=NMAX*NMAX+4*NMAX+1,LIWORK=5*NMAX+3) * .. Local Scalars .. INTEGER I, IFAIL, INFO, N CHARACTER JOB * .. Local Arrays .. DOUBLE PRECISION D(NMAX), E(NMAX), WORK(LWORK), Z(LDZ,NMAX) INTEGER IWORK(LIWORK) * .. External Subroutines .. EXTERNAL DSTEVD, X04CAF * .. Executable Statements .. WRITE (NOUT,*) 'F08JCF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N IF (N.LE.NMAX) THEN * * Read T from data file * READ (NIN,*) (D(I),I=1,N) READ (NIN,*) (E(I),I=1,N-1) * READ (NIN,*) JOB * * Calculate all the eigenvalues and eigenvectors of T * CALL DSTEVD(JOB,N,D,E,Z,LDZ,WORK,LWORK,IWORK,LIWORK,INFO) * WRITE (NOUT,*) IF (INFO.GT.0) THEN WRITE (NOUT,*) 'Failure to converge.' ELSE * * Print eigenvalues and eigenvectors * WRITE (NOUT,*) 'Eigenvalues' WRITE (NOUT,99999) (D(I),I=1,N) WRITE (NOUT,*) IFAIL = 0 * CALL X04CAF('General',' ',N,N,Z,LDZ,'Eigenvectors',IFAIL) * END IF END IF STOP * 99999 FORMAT (3X,(8F8.4)) END