#include "blaswrap.h" #include "f2c.h" /* Subroutine */ int zggevx_(char *balanc, char *jobvl, char *jobvr, char * sense, integer *n, doublecomplex *a, integer *lda, doublecomplex *b, integer *ldb, doublecomplex *alpha, doublecomplex *beta, doublecomplex *vl, integer *ldvl, doublecomplex *vr, integer *ldvr, integer *ilo, integer *ihi, doublereal *lscale, doublereal *rscale, doublereal *abnrm, doublereal *bbnrm, doublereal *rconde, doublereal * rcondv, doublecomplex *work, integer *lwork, doublereal *rwork, integer *iwork, logical *bwork, integer *info) { /* -- LAPACK driver routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= ZGGEVX computes for a pair of N-by-N complex nonsymmetric matrices (A,B) the generalized eigenvalues, and optionally, the left and/or right generalized eigenvectors. Optionally, it also computes a balancing transformation to improve the conditioning of the eigenvalues and eigenvectors (ILO, IHI, LSCALE, RSCALE, ABNRM, and BBNRM), reciprocal condition numbers for the eigenvalues (RCONDE), and reciprocal condition numbers for the right eigenvectors (RCONDV). A generalized eigenvalue for a pair of matrices (A,B) is a scalar lambda or a ratio alpha/beta = lambda, such that A - lambda*B is singular. It is usually represented as the pair (alpha,beta), as there is a reasonable interpretation for beta=0, and even for both being zero. The right eigenvector v(j) corresponding to the eigenvalue lambda(j) of (A,B) satisfies A * v(j) = lambda(j) * B * v(j) . The left eigenvector u(j) corresponding to the eigenvalue lambda(j) of (A,B) satisfies u(j)**H * A = lambda(j) * u(j)**H * B. where u(j)**H is the conjugate-transpose of u(j). Arguments ========= BALANC (input) CHARACTER*1 Specifies the balance option to be performed: = 'N': do not diagonally scale or permute; = 'P': permute only; = 'S': scale only; = 'B': both permute and scale. Computed reciprocal condition numbers will be for the matrices after permuting and/or balancing. Permuting does not change condition numbers (in exact arithmetic), but balancing does. JOBVL (input) CHARACTER*1 = 'N': do not compute the left generalized eigenvectors; = 'V': compute the left generalized eigenvectors. JOBVR (input) CHARACTER*1 = 'N': do not compute the right generalized eigenvectors; = 'V': compute the right generalized eigenvectors. SENSE (input) CHARACTER*1 Determines which reciprocal condition numbers are computed. = 'N': none are computed; = 'E': computed for eigenvalues only; = 'V': computed for eigenvectors only; = 'B': computed for eigenvalues and eigenvectors. N (input) INTEGER The order of the matrices A, B, VL, and VR. N >= 0. A (input/output) COMPLEX*16 array, dimension (LDA, N) On entry, the matrix A in the pair (A,B). On exit, A has been overwritten. If JOBVL='V' or JOBVR='V' or both, then A contains the first part of the complex Schur form of the "balanced" versions of the input A and B. LDA (input) INTEGER The leading dimension of A. LDA >= max(1,N). B (input/output) COMPLEX*16 array, dimension (LDB, N) On entry, the matrix B in the pair (A,B). On exit, B has been overwritten. If JOBVL='V' or JOBVR='V' or both, then B contains the second part of the complex Schur form of the "balanced" versions of the input A and B. LDB (input) INTEGER The leading dimension of B. LDB >= max(1,N). ALPHA (output) COMPLEX*16 array, dimension (N) BETA (output) COMPLEX*16 array, dimension (N) On exit, ALPHA(j)/BETA(j), j=1,...,N, will be the generalized eigenvalues. Note: the quotient ALPHA(j)/BETA(j) ) may easily over- or underflow, and BETA(j) may even be zero. Thus, the user should avoid naively computing the ratio ALPHA/BETA. However, ALPHA will be always less than and usually comparable with norm(A) in magnitude, and BETA always less than and usually comparable with norm(B). VL (output) COMPLEX*16 array, dimension (LDVL,N) If JOBVL = 'V', the left generalized eigenvectors u(j) are stored one after another in the columns of VL, in the same order as their eigenvalues. Each eigenvector will be scaled so the largest component will have abs(real part) + abs(imag. part) = 1. Not referenced if JOBVL = 'N'. LDVL (input) INTEGER The leading dimension of the matrix VL. LDVL >= 1, and if JOBVL = 'V', LDVL >= N. VR (output) COMPLEX*16 array, dimension (LDVR,N) If JOBVR = 'V', the right generalized eigenvectors v(j) are stored one after another in the columns of VR, in the same order as their eigenvalues. Each eigenvector will be scaled so the largest component will have abs(real part) + abs(imag. part) = 1. Not referenced if JOBVR = 'N'. LDVR (input) INTEGER The leading dimension of the matrix VR. LDVR >= 1, and if JOBVR = 'V', LDVR >= N. ILO (output) INTEGER IHI (output) INTEGER ILO and IHI are integer values such that on exit A(i,j) = 0 and B(i,j) = 0 if i > j and j = 1,...,ILO-1 or i = IHI+1,...,N. If BALANC = 'N' or 'S', ILO = 1 and IHI = N. LSCALE (output) DOUBLE PRECISION array, dimension (N) Details of the permutations and scaling factors applied to the left side of A and B. If PL(j) is the index of the row interchanged with row j, and DL(j) is the scaling factor applied to row j, then LSCALE(j) = PL(j) for j = 1,...,ILO-1 = DL(j) for j = ILO,...,IHI = PL(j) for j = IHI+1,...,N. The order in which the interchanges are made is N to IHI+1, then 1 to ILO-1. RSCALE (output) DOUBLE PRECISION array, dimension (N) Details of the permutations and scaling factors applied to the right side of A and B. If PR(j) is the index of the column interchanged with column j, and DR(j) is the scaling factor applied to column j, then RSCALE(j) = PR(j) for j = 1,...,ILO-1 = DR(j) for j = ILO,...,IHI = PR(j) for j = IHI+1,...,N The order in which the interchanges are made is N to IHI+1, then 1 to ILO-1. ABNRM (output) DOUBLE PRECISION The one-norm of the balanced matrix A. BBNRM (output) DOUBLE PRECISION The one-norm of the balanced matrix B. RCONDE (output) DOUBLE PRECISION array, dimension (N) If SENSE = 'E' or 'B', the reciprocal condition numbers of the eigenvalues, stored in consecutive elements of the array. If SENSE = 'N' or 'V', RCONDE is not referenced. RCONDV (output) DOUBLE PRECISION array, dimension (N) If JOB = 'V' or 'B', the estimated reciprocal condition numbers of the eigenvectors, stored in consecutive elements of the array. If the eigenvalues cannot be reordered to compute RCONDV(j), RCONDV(j) is set to 0; this can only occur when the true value would be very small anyway. If SENSE = 'N' or 'E', RCONDV is not referenced. WORK (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. LWORK (input) INTEGER The dimension of the array WORK. LWORK >= max(1,2*N). If SENSE = 'E', LWORK >= max(1,4*N). If SENSE = 'V' or 'B', LWORK >= max(1,2*N*N+2*N). If LWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the WORK array, returns this value as the first entry of the WORK array, and no error message related to LWORK is issued by XERBLA. RWORK (workspace) REAL array, dimension (lrwork) lrwork must be at least max(1,6*N) if BALANC = 'S' or 'B', and at least max(1,2*N) otherwise. Real workspace. IWORK (workspace) INTEGER array, dimension (N+2) If SENSE = 'E', IWORK is not referenced. BWORK (workspace) LOGICAL array, dimension (N) If SENSE = 'N', BWORK is not referenced. INFO (output) INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value. = 1,...,N: The QZ iteration failed. No eigenvectors have been calculated, but ALPHA(j) and BETA(j) should be correct for j=INFO+1,...,N. > N: =N+1: other than QZ iteration failed in ZHGEQZ. =N+2: error return from ZTGEVC. Further Details =============== Balancing a matrix pair (A,B) includes, first, permuting rows and columns to isolate eigenvalues, second, applying diagonal similarity transformation to the rows and columns to make the rows and columns as close in norm as possible. The computed reciprocal condition numbers correspond to the balanced matrix. Permuting rows and columns will not change the condition numbers (in exact arithmetic) but diagonal scaling will. For further explanation of balancing, see section 4.11.1.2 of LAPACK Users' Guide. An approximate error bound on the chordal distance between the i-th computed generalized eigenvalue w and the corresponding exact eigenvalue lambda is chord(w, lambda) <= EPS * norm(ABNRM, BBNRM) / RCONDE(I) An approximate error bound for the angle between the i-th computed eigenvector VL(i) or VR(i) is given by EPS * norm(ABNRM, BBNRM) / DIF(i). For further explanation of the reciprocal condition numbers RCONDE and RCONDV, see section 4.11 of LAPACK User's Guide. Decode the input arguments Parameter adjustments */ /* Table of constant values */ static doublecomplex c_b1 = {0.,0.}; static doublecomplex c_b2 = {1.,0.}; static integer c__1 = 1; static integer c__0 = 0; /* System generated locals */ integer a_dim1, a_offset, b_dim1, b_offset, vl_dim1, vl_offset, vr_dim1, vr_offset, i__1, i__2, i__3, i__4; doublereal d__1, d__2, d__3, d__4; doublecomplex z__1; /* Builtin functions */ double sqrt(doublereal), d_imag(doublecomplex *); /* Local variables */ static integer i__, j, m, jc, in, jr; static doublereal eps; static logical ilv; static doublereal anrm, bnrm; static integer ierr, itau; static doublereal temp; static logical ilvl, ilvr; static integer iwrk, iwrk1; extern logical lsame_(char *, char *); static integer icols; static logical noscl; static integer irows; extern /* Subroutine */ int dlabad_(doublereal *, doublereal *); extern doublereal dlamch_(char *); extern /* Subroutine */ int dlascl_(char *, integer *, integer *, doublereal *, doublereal *, integer *, integer *, doublereal *, integer *, integer *), zggbak_(char *, char *, integer *, integer *, integer *, doublereal *, doublereal *, integer *, doublecomplex *, integer *, integer *), zggbal_( char *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, integer *, doublereal *, doublereal *, doublereal *, integer *); static logical ilascl, ilbscl; extern /* Subroutine */ int xerbla_(char *, integer *); extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *, ftnlen, ftnlen); static logical ldumma[1]; static char chtemp[1]; static doublereal bignum; extern doublereal zlange_(char *, integer *, integer *, doublecomplex *, integer *, doublereal *); static integer ijobvl; extern /* Subroutine */ int zgghrd_(char *, char *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer * ), zlascl_(char *, integer *, integer *, doublereal *, doublereal *, integer *, integer *, doublecomplex *, integer *, integer *); static integer ijobvr; static logical wantsb; extern /* Subroutine */ int zgeqrf_(integer *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, integer *, integer * ); static doublereal anrmto; static logical wantse; static doublereal bnrmto; extern /* Subroutine */ int zlacpy_(char *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *), zlaset_(char *, integer *, integer *, doublecomplex *, doublecomplex *, doublecomplex *, integer *), ztgevc_( char *, char *, logical *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, integer *, integer *, doublecomplex *, doublereal *, integer *), ztgsna_(char *, char *, logical *, integer *, doublecomplex *, integer *, doublecomplex * , integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, doublereal *, integer *, integer *, doublecomplex *, integer *, integer *, integer *); static integer minwrk; extern /* Subroutine */ int zhgeqz_(char *, char *, char *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, doublecomplex *, integer *, doublecomplex *, integer *, doublecomplex *, integer *, doublereal *, integer *); static integer maxwrk; static logical wantsn; static doublereal smlnum; static logical lquery, wantsv; extern /* Subroutine */ int zungqr_(integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, integer *, integer *), zunmqr_(char *, char *, integer *, integer *, integer *, doublecomplex *, integer *, doublecomplex *, doublecomplex *, integer *, doublecomplex *, integer *, integer *); a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; b_dim1 = *ldb; b_offset = 1 + b_dim1; b -= b_offset; --alpha; --beta; vl_dim1 = *ldvl; vl_offset = 1 + vl_dim1; vl -= vl_offset; vr_dim1 = *ldvr; vr_offset = 1 + vr_dim1; vr -= vr_offset; --lscale; --rscale; --rconde; --rcondv; --work; --rwork; --iwork; --bwork; /* Function Body */ if (lsame_(jobvl, "N")) { ijobvl = 1; ilvl = FALSE_; } else if (lsame_(jobvl, "V")) { ijobvl = 2; ilvl = TRUE_; } else { ijobvl = -1; ilvl = FALSE_; } if (lsame_(jobvr, "N")) { ijobvr = 1; ilvr = FALSE_; } else if (lsame_(jobvr, "V")) { ijobvr = 2; ilvr = TRUE_; } else { ijobvr = -1; ilvr = FALSE_; } ilv = ilvl || ilvr; noscl = lsame_(balanc, "N") || lsame_(balanc, "P"); wantsn = lsame_(sense, "N"); wantse = lsame_(sense, "E"); wantsv = lsame_(sense, "V"); wantsb = lsame_(sense, "B"); /* Test the input arguments */ *info = 0; lquery = *lwork == -1; if (! (noscl || lsame_(balanc, "S") || lsame_( balanc, "B"))) { *info = -1; } else if (ijobvl <= 0) { *info = -2; } else if (ijobvr <= 0) { *info = -3; } else if (! (wantsn || wantse || wantsb || wantsv)) { *info = -4; } else if (*n < 0) { *info = -5; } else if (*lda < max(1,*n)) { *info = -7; } else if (*ldb < max(1,*n)) { *info = -9; } else if (*ldvl < 1 || ilvl && *ldvl < *n) { *info = -13; } else if (*ldvr < 1 || ilvr && *ldvr < *n) { *info = -15; } /* Compute workspace (Note: Comments in the code beginning "Workspace:" describe the minimal amount of workspace needed at that point in the code, as well as the preferred amount for good performance. NB refers to the optimal block size for the immediately following subroutine, as returned by ILAENV. The workspace is computed assuming ILO = 1 and IHI = N, the worst case.) */ if (*info == 0) { if (*n == 0) { minwrk = 1; maxwrk = 1; } else { minwrk = *n << 1; if (wantse) { minwrk = *n << 2; } else if (wantsv || wantsb) { minwrk = (*n << 1) * (*n + 1); } maxwrk = minwrk; /* Computing MAX */ i__1 = maxwrk, i__2 = *n + *n * ilaenv_(&c__1, "ZGEQRF", " ", n, & c__1, n, &c__0, (ftnlen)6, (ftnlen)1); maxwrk = max(i__1,i__2); /* Computing MAX */ i__1 = maxwrk, i__2 = *n + *n * ilaenv_(&c__1, "ZUNMQR", " ", n, & c__1, n, &c__0, (ftnlen)6, (ftnlen)1); maxwrk = max(i__1,i__2); if (ilvl) { /* Computing MAX */ i__1 = maxwrk, i__2 = *n + *n * ilaenv_(&c__1, "ZUNGQR", " ", n, &c__1, n, &c__0, (ftnlen)6, (ftnlen)1); maxwrk = max(i__1,i__2); } } work[1].r = (doublereal) maxwrk, work[1].i = 0.; if (*lwork < minwrk && ! lquery) { *info = -25; } } if (*info != 0) { i__1 = -(*info); xerbla_("ZGGEVX", &i__1); return 0; } else if (lquery) { return 0; } /* Quick return if possible */ if (*n == 0) { return 0; } /* Get machine constants */ eps = dlamch_("P"); smlnum = dlamch_("S"); bignum = 1. / smlnum; dlabad_(&smlnum, &bignum); smlnum = sqrt(smlnum) / eps; bignum = 1. / smlnum; /* Scale A if max element outside range [SMLNUM,BIGNUM] */ anrm = zlange_("M", n, n, &a[a_offset], lda, &rwork[1]); ilascl = FALSE_; if (anrm > 0. && anrm < smlnum) { anrmto = smlnum; ilascl = TRUE_; } else if (anrm > bignum) { anrmto = bignum; ilascl = TRUE_; } if (ilascl) { zlascl_("G", &c__0, &c__0, &anrm, &anrmto, n, n, &a[a_offset], lda, & ierr); } /* Scale B if max element outside range [SMLNUM,BIGNUM] */ bnrm = zlange_("M", n, n, &b[b_offset], ldb, &rwork[1]); ilbscl = FALSE_; if (bnrm > 0. && bnrm < smlnum) { bnrmto = smlnum; ilbscl = TRUE_; } else if (bnrm > bignum) { bnrmto = bignum; ilbscl = TRUE_; } if (ilbscl) { zlascl_("G", &c__0, &c__0, &bnrm, &bnrmto, n, n, &b[b_offset], ldb, & ierr); } /* Permute and/or balance the matrix pair (A,B) (Real Workspace: need 6*N if BALANC = 'S' or 'B', 1 otherwise) */ zggbal_(balanc, n, &a[a_offset], lda, &b[b_offset], ldb, ilo, ihi, & lscale[1], &rscale[1], &rwork[1], &ierr); /* Compute ABNRM and BBNRM */ *abnrm = zlange_("1", n, n, &a[a_offset], lda, &rwork[1]); if (ilascl) { rwork[1] = *abnrm; dlascl_("G", &c__0, &c__0, &anrmto, &anrm, &c__1, &c__1, &rwork[1], & c__1, &ierr); *abnrm = rwork[1]; } *bbnrm = zlange_("1", n, n, &b[b_offset], ldb, &rwork[1]); if (ilbscl) { rwork[1] = *bbnrm; dlascl_("G", &c__0, &c__0, &bnrmto, &bnrm, &c__1, &c__1, &rwork[1], & c__1, &ierr); *bbnrm = rwork[1]; } /* Reduce B to triangular form (QR decomposition of B) (Complex Workspace: need N, prefer N*NB ) */ irows = *ihi + 1 - *ilo; if (ilv || ! wantsn) { icols = *n + 1 - *ilo; } else { icols = irows; } itau = 1; iwrk = itau + irows; i__1 = *lwork + 1 - iwrk; zgeqrf_(&irows, &icols, &b[*ilo + *ilo * b_dim1], ldb, &work[itau], &work[ iwrk], &i__1, &ierr); /* Apply the unitary transformation to A (Complex Workspace: need N, prefer N*NB) */ i__1 = *lwork + 1 - iwrk; zunmqr_("L", "C", &irows, &icols, &irows, &b[*ilo + *ilo * b_dim1], ldb, & work[itau], &a[*ilo + *ilo * a_dim1], lda, &work[iwrk], &i__1, & ierr); /* Initialize VL and/or VR (Workspace: need N, prefer N*NB) */ if (ilvl) { zlaset_("Full", n, n, &c_b1, &c_b2, &vl[vl_offset], ldvl); if (irows > 1) { i__1 = irows - 1; i__2 = irows - 1; zlacpy_("L", &i__1, &i__2, &b[*ilo + 1 + *ilo * b_dim1], ldb, &vl[ *ilo + 1 + *ilo * vl_dim1], ldvl); } i__1 = *lwork + 1 - iwrk; zungqr_(&irows, &irows, &irows, &vl[*ilo + *ilo * vl_dim1], ldvl, & work[itau], &work[iwrk], &i__1, &ierr); } if (ilvr) { zlaset_("Full", n, n, &c_b1, &c_b2, &vr[vr_offset], ldvr); } /* Reduce to generalized Hessenberg form (Workspace: none needed) */ if (ilv || ! wantsn) { /* Eigenvectors requested -- work on whole matrix. */ zgghrd_(jobvl, jobvr, n, ilo, ihi, &a[a_offset], lda, &b[b_offset], ldb, &vl[vl_offset], ldvl, &vr[vr_offset], ldvr, &ierr); } else { zgghrd_("N", "N", &irows, &c__1, &irows, &a[*ilo + *ilo * a_dim1], lda, &b[*ilo + *ilo * b_dim1], ldb, &vl[vl_offset], ldvl, &vr[ vr_offset], ldvr, &ierr); } /* Perform QZ algorithm (Compute eigenvalues, and optionally, the Schur forms and Schur vectors) (Complex Workspace: need N) (Real Workspace: need N) */ iwrk = itau; if (ilv || ! wantsn) { *(unsigned char *)chtemp = 'S'; } else { *(unsigned char *)chtemp = 'E'; } i__1 = *lwork + 1 - iwrk; zhgeqz_(chtemp, jobvl, jobvr, n, ilo, ihi, &a[a_offset], lda, &b[b_offset] , ldb, &alpha[1], &beta[1], &vl[vl_offset], ldvl, &vr[vr_offset], ldvr, &work[iwrk], &i__1, &rwork[1], &ierr); if (ierr != 0) { if (ierr > 0 && ierr <= *n) { *info = ierr; } else if (ierr > *n && ierr <= *n << 1) { *info = ierr - *n; } else { *info = *n + 1; } goto L90; } /* Compute Eigenvectors and estimate condition numbers if desired ZTGEVC: (Complex Workspace: need 2*N ) (Real Workspace: need 2*N ) ZTGSNA: (Complex Workspace: need 2*N*N if SENSE='V' or 'B') (Integer Workspace: need N+2 ) */ if (ilv || ! wantsn) { if (ilv) { if (ilvl) { if (ilvr) { *(unsigned char *)chtemp = 'B'; } else { *(unsigned char *)chtemp = 'L'; } } else { *(unsigned char *)chtemp = 'R'; } ztgevc_(chtemp, "B", ldumma, n, &a[a_offset], lda, &b[b_offset], ldb, &vl[vl_offset], ldvl, &vr[vr_offset], ldvr, n, &in, & work[iwrk], &rwork[1], &ierr); if (ierr != 0) { *info = *n + 2; goto L90; } } if (! wantsn) { /* compute eigenvectors (DTGEVC) and estimate condition numbers (DTGSNA). Note that the definition of the condition number is not invariant under transformation (u,v) to (Q*u, Z*v), where (u,v) are eigenvectors of the generalized Schur form (S,T), Q and Z are orthogonal matrices. In order to avoid using extra 2*N*N workspace, we have to re-calculate eigenvectors and estimate the condition numbers one at a time. */ i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { i__2 = *n; for (j = 1; j <= i__2; ++j) { bwork[j] = FALSE_; /* L10: */ } bwork[i__] = TRUE_; iwrk = *n + 1; iwrk1 = iwrk + *n; if (wantse || wantsb) { ztgevc_("B", "S", &bwork[1], n, &a[a_offset], lda, &b[ b_offset], ldb, &work[1], n, &work[iwrk], n, & c__1, &m, &work[iwrk1], &rwork[1], &ierr); if (ierr != 0) { *info = *n + 2; goto L90; } } i__2 = *lwork - iwrk1 + 1; ztgsna_(sense, "S", &bwork[1], n, &a[a_offset], lda, &b[ b_offset], ldb, &work[1], n, &work[iwrk], n, &rconde[ i__], &rcondv[i__], &c__1, &m, &work[iwrk1], &i__2, & iwork[1], &ierr); /* L20: */ } } } /* Undo balancing on VL and VR and normalization (Workspace: none needed) */ if (ilvl) { zggbak_(balanc, "L", n, ilo, ihi, &lscale[1], &rscale[1], n, &vl[ vl_offset], ldvl, &ierr); i__1 = *n; for (jc = 1; jc <= i__1; ++jc) { temp = 0.; i__2 = *n; for (jr = 1; jr <= i__2; ++jr) { /* Computing MAX */ i__3 = jr + jc * vl_dim1; d__3 = temp, d__4 = (d__1 = vl[i__3].r, abs(d__1)) + (d__2 = d_imag(&vl[jr + jc * vl_dim1]), abs(d__2)); temp = max(d__3,d__4); /* L30: */ } if (temp < smlnum) { goto L50; } temp = 1. / temp; i__2 = *n; for (jr = 1; jr <= i__2; ++jr) { i__3 = jr + jc * vl_dim1; i__4 = jr + jc * vl_dim1; z__1.r = temp * vl[i__4].r, z__1.i = temp * vl[i__4].i; vl[i__3].r = z__1.r, vl[i__3].i = z__1.i; /* L40: */ } L50: ; } } if (ilvr) { zggbak_(balanc, "R", n, ilo, ihi, &lscale[1], &rscale[1], n, &vr[ vr_offset], ldvr, &ierr); i__1 = *n; for (jc = 1; jc <= i__1; ++jc) { temp = 0.; i__2 = *n; for (jr = 1; jr <= i__2; ++jr) { /* Computing MAX */ i__3 = jr + jc * vr_dim1; d__3 = temp, d__4 = (d__1 = vr[i__3].r, abs(d__1)) + (d__2 = d_imag(&vr[jr + jc * vr_dim1]), abs(d__2)); temp = max(d__3,d__4); /* L60: */ } if (temp < smlnum) { goto L80; } temp = 1. / temp; i__2 = *n; for (jr = 1; jr <= i__2; ++jr) { i__3 = jr + jc * vr_dim1; i__4 = jr + jc * vr_dim1; z__1.r = temp * vr[i__4].r, z__1.i = temp * vr[i__4].i; vr[i__3].r = z__1.r, vr[i__3].i = z__1.i; /* L70: */ } L80: ; } } /* Undo scaling if necessary */ if (ilascl) { zlascl_("G", &c__0, &c__0, &anrmto, &anrm, n, &c__1, &alpha[1], n, & ierr); } if (ilbscl) { zlascl_("G", &c__0, &c__0, &bnrmto, &bnrm, n, &c__1, &beta[1], n, & ierr); } L90: work[1].r = (doublereal) maxwrk, work[1].i = 0.; return 0; /* End of ZGGEVX */ } /* zggevx_ */