* F08GQF 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, LRWORK, MMAX PARAMETER (LWORK=2*NMAX,LIWORK=5*NMAX+3, + LRWORK=2*NMAX*NMAX+5*NMAX+1,MMAX=NMAX*(NMAX+1)/2) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, N CHARACTER JOB, UPLO * .. Local Arrays .. COMPLEX*16 AP(MMAX), WORK(LWORK), Z(LDZ,NMAX) DOUBLE PRECISION RWORK(LRWORK), W(NMAX) INTEGER IWORK(LIWORK) * .. External Subroutines .. EXTERNAL X04DAF, ZHPEVD * .. Executable Statements .. WRITE (NOUT,*) 'F08GQF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N IF (N.LE.NMAX) THEN READ (NIN,*) UPLO * * Read A from data file * 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 ZHPEVD(JOB,UPLO,N,AP,W,Z,LDZ,WORK,LWORK,RWORK,LRWORK, + IWORK,LIWORK,INFO) * WRITE (NOUT,*) IF (INFO.GT.0) THEN WRITE (NOUT,*) 'Failure to converge.' ELSE * * Print eigenvalues and eigenvectors * WRITE (NOUT,*) 'Eigenvalues' DO 20 I = 1, N WRITE (NOUT,99999) I, W(I) 20 CONTINUE WRITE (NOUT,*) IFAIL = 0 * CALL X04DAF('General',' ',N,N,Z,LDZ,'Eigenvectors',IFAIL) * END IF END IF STOP * 99999 FORMAT (3X,I5,5X,2F8.4) END