* F08GCF 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+6*NMAX+1,LIWORK=5*NMAX+3) INTEGER MMAX PARAMETER (MMAX=NMAX*(NMAX+1)/2) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, N CHARACTER JOB, UPLO * .. Local Arrays .. DOUBLE PRECISION AP(MMAX), W(NMAX), WORK(LWORK), Z(LDZ,NMAX) INTEGER IWORK(LIWORK) * .. External Subroutines .. EXTERNAL DSPEVD, X04CAF * .. Executable Statements .. WRITE (NOUT,*) 'F08GCF 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,*) UPLO IF (UPLO.EQ.'U') THEN READ (NIN,*) ((AP(I+J*(J-1)/2),J=I,N),I=1,N) ELSE IF (UPLO.EQ.'L') THEN READ (NIN,*) ((AP(I+(2*N-J)*(J-1)/2),J=1,I),I=1,N) END IF * READ (NIN,*) JOB * * Calculate all the eigenvalues and eigenvectors of A * CALL DSPEVD(JOB,UPLO,N,AP,W,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) (W(I),I=1,N) WRITE (NOUT,*) IFAIL = 0 * CALL X04CAF('General',' ',N,N,Z,LDZ,'Eigenvectors',IFAIL) * END IF END IF * 99999 FORMAT (3X,(8F8.4)) END