* F07BEF Example Program Text * Mark 15 Release. NAG Copyright 1991. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, KLMAX, KUMAX, LDAB, NRHMAX, LDB PARAMETER (NMAX=8,KLMAX=8,KUMAX=8,LDAB=2*KLMAX+KUMAX+1, + NRHMAX=NMAX,LDB=NMAX) CHARACTER TRANS PARAMETER (TRANS='N') * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, K, KL, KU, N, NRHS * .. Local Arrays .. DOUBLE PRECISION AB(LDAB,NMAX), B(LDB,NRHMAX) INTEGER IPIV(NMAX) * .. External Subroutines .. EXTERNAL DGBTRF, DGBTRS, X04CAF * .. Intrinsic Functions .. INTRINSIC MAX, MIN * .. Executable Statements .. WRITE (NOUT,*) 'F07BEF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N, NRHS, KL, KU IF (N.LE.NMAX .AND. NRHS.LE.NRHMAX .AND. KL.LE.KLMAX .AND. KU.LE. + KUMAX) THEN * * Read A and B from data file * K = KL + KU + 1 READ (NIN,*) ((AB(K+I-J,J),J=MAX(I-KL,1),MIN(I+KU,N)),I=1,N) READ (NIN,*) ((B(I,J),J=1,NRHS),I=1,N) * * Factorize A * CALL DGBTRF(N,N,KL,KU,AB,LDAB,IPIV,INFO) * WRITE (NOUT,*) IF (INFO.EQ.0) THEN * * Compute solution * CALL DGBTRS(TRANS,N,KL,KU,NRHS,AB,LDAB,IPIV,B,LDB,INFO) * * Print solution * IFAIL = 0 * CALL X04CAF('General',' ',N,NRHS,B,LDB,'Solution(s)',IFAIL) * ELSE WRITE (NOUT,*) 'The factor U is singular' END IF END IF STOP * END