* F08HCF Example Program Text * Mark 20 Revised. NAG Copyright 2001. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, KDMAX, LDAB, LDZ PARAMETER (NMAX=9,KDMAX=4,LDAB=KDMAX,LDZ=NMAX) INTEGER LWORK, LIWORK PARAMETER (LWORK=2*NMAX*NMAX+5*NMAX+1,LIWORK=5*NMAX+3) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, KD, N CHARACTER JOB, UPLO * .. Local Arrays .. DOUBLE PRECISION AB(LDAB,NMAX), W(NMAX), WORK(LWORK), Z(LDZ,NMAX) INTEGER IWORK(LIWORK) * .. External Subroutines .. EXTERNAL DSBEVD, X04CAF * .. Intrinsic Functions .. INTRINSIC MAX, MIN * .. Executable Statements .. WRITE (NOUT,*) 'F08HCF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N, KD IF (N.LE.NMAX) THEN * * Read A from data file * READ (NIN,*) UPLO IF (UPLO.EQ.'U') THEN DO 20 I = 1, N READ (NIN,*) (AB(KD+1+I-J,J),J=I,MIN(N,I+KD)) 20 CONTINUE ELSE IF (UPLO.EQ.'L') THEN DO 40 I = 1, N READ (NIN,*) (AB(1+I-J,J),J=MAX(1,I-KD),I) 40 CONTINUE END IF * READ (NIN,*) JOB * * Calculate all the eigenvalues and eigenvectors of A * CALL DSBEVD(JOB,UPLO,N,KD,AB,LDAB,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 STOP * 99999 FORMAT (3X,(8F8.4)) END