* F07VSF Example Program Text * Mark 15 Release. NAG Copyright 1991. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, KDMAX, LDAB, NRHMAX, LDB PARAMETER (NMAX=8,KDMAX=NMAX,LDAB=KDMAX+1,NRHMAX=NMAX, + LDB=NMAX) CHARACTER TRANS, DIAG PARAMETER (TRANS='N',DIAG='N') * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, KD, N, NRHS CHARACTER UPLO * .. Local Arrays .. COMPLEX*16 AB(LDAB,NMAX), B(LDB,NRHMAX) CHARACTER CLABS(1), RLABS(1) * .. External Subroutines .. EXTERNAL ZTBTRS, X04DBF * .. Intrinsic Functions .. INTRINSIC MAX, MIN * .. Executable Statements .. WRITE (NOUT,*) 'F07VSF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N, KD, NRHS IF (N.LE.NMAX .AND. KD.LE.KDMAX .AND. NRHS.LE.NRHMAX) THEN * * Read A and B 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,*) ((B(I,J),J=1,NRHS),I=1,N) * * Compute solution * CALL ZTBTRS(UPLO,TRANS,DIAG,N,KD,NRHS,AB,LDAB,B,LDB,INFO) * * Print solution * WRITE (NOUT,*) IF (INFO.EQ.0) THEN IFAIL = 0 CALL X04DBF('General',' ',N,NRHS,B,LDB,'Bracketed','F7.4', + 'Solution(s)','Integer',RLABS,'Integer',CLABS, + 80,0,IFAIL) ELSE WRITE (NOUT,*) 'A is singular' END IF END IF STOP * END