* F08ASF Example Program Text * Mark 16 Release. NAG Copyright 1992. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER MMAX, NMAX, LDA, LDB, NRHMAX, LWORK PARAMETER (MMAX=8,NMAX=8,LDA=MMAX,LDB=MMAX,NRHMAX=NMAX, + LWORK=64*NMAX) COMPLEX*16 ONE PARAMETER (ONE=(1.0D0,0.0D0)) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, M, N, NRHS * .. Local Arrays .. COMPLEX*16 A(LDA,NMAX), B(LDB,NRHMAX), TAU(NMAX), + WORK(LWORK) CHARACTER CLABS(1), RLABS(1) * .. External Subroutines .. EXTERNAL X04DBF, ZGEQRF, ZTRSM, ZUNMQR * .. Executable Statements .. WRITE (NOUT,*) 'F08ASF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) M, N, NRHS IF (M.LE.MMAX .AND. N.LE.NMAX .AND. M.GE.N .AND. NRHS.LE.NRHMAX) + THEN * * Read A and B from data file * READ (NIN,*) ((A(I,J),J=1,N),I=1,M) READ (NIN,*) ((B(I,J),J=1,NRHS),I=1,M) * * Compute the QR factorization of A * CALL ZGEQRF(M,N,A,LDA,TAU,WORK,LWORK,INFO) * * Compute C = (Q**H)*B, storing the result in B * CALL ZUNMQR('Left','Conjugate transpose',M,NRHS,N,A,LDA,TAU,B, + LDB,WORK,LWORK,INFO) * * Compute least-squares solution by backsubstitution in R*X = C * CALL ZTRSM('Left','Upper','No transpose','Non-Unit',N,NRHS,ONE, + A,LDA,B,LDB) * * Print least-squares solution(s) * WRITE (NOUT,*) IFAIL = 0 * CALL X04DBF('General',' ',N,NRHS,B,LDB,'Bracketed','F7.4', + 'Least-squares solution(s)','Integer',RLABS, + 'Integer',CLABS,80,0,IFAIL) * END IF STOP END