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/* cgees.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
#include "blaswrap.h"
/* Table of constant values */
static integer c__1 = 1;
static integer c__0 = 0;
static integer c_n1 = -1;
/* Subroutine */ int cgees_(char *jobvs, char *sort, L_fp select, integer *n,
complex *a, integer *lda, integer *sdim, complex *w, complex *vs,
integer *ldvs, complex *work, integer *lwork, real *rwork, logical *
bwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, vs_dim1, vs_offset, i__1, i__2;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
integer i__;
real s;
integer ihi, ilo;
real dum[1], eps, sep;
integer ibal;
real anrm;
integer ierr, itau, iwrk, icond, ieval;
extern logical lsame_(char *, char *);
extern /* Subroutine */ int ccopy_(integer *, complex *, integer *,
complex *, integer *), cgebak_(char *, char *, integer *, integer
*, integer *, real *, integer *, complex *, integer *, integer *), cgebal_(char *, integer *, complex *, integer *,
integer *, integer *, real *, integer *), slabad_(real *,
real *);
logical scalea;
extern doublereal clange_(char *, integer *, integer *, complex *,
integer *, real *);
real cscale;
extern /* Subroutine */ int cgehrd_(integer *, integer *, integer *,
complex *, integer *, complex *, complex *, integer *, integer *),
clascl_(char *, integer *, integer *, real *, real *, integer *,
integer *, complex *, integer *, integer *);
extern doublereal slamch_(char *);
extern /* Subroutine */ int clacpy_(char *, integer *, integer *, complex
*, integer *, complex *, integer *), xerbla_(char *,
integer *);
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
real bignum;
extern /* Subroutine */ int chseqr_(char *, char *, integer *, integer *,
integer *, complex *, integer *, complex *, complex *, integer *,
complex *, integer *, integer *), cunghr_(integer
*, integer *, integer *, complex *, integer *, complex *, complex
*, integer *, integer *), ctrsen_(char *, char *, logical *,
integer *, complex *, integer *, complex *, integer *, complex *,
integer *, real *, real *, complex *, integer *, integer *);
integer minwrk, maxwrk;
real smlnum;
integer hswork;
logical wantst, lquery, wantvs;
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* .. Function Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CGEES computes for an N-by-N complex nonsymmetric matrix A, the */
/* eigenvalues, the Schur form T, and, optionally, the matrix of Schur */
/* vectors Z. This gives the Schur factorization A = Z*T*(Z**H). */
/* Optionally, it also orders the eigenvalues on the diagonal of the */
/* Schur form so that selected eigenvalues are at the top left. */
/* The leading columns of Z then form an orthonormal basis for the */
/* invariant subspace corresponding to the selected eigenvalues. */
/* A complex matrix is in Schur form if it is upper triangular. */
/* Arguments */
/* ========= */
/* JOBVS (input) CHARACTER*1 */
/* = 'N': Schur vectors are not computed; */
/* = 'V': Schur vectors are computed. */
/* SORT (input) CHARACTER*1 */
/* Specifies whether or not to order the eigenvalues on the */
/* diagonal of the Schur form. */
/* = 'N': Eigenvalues are not ordered: */
/* = 'S': Eigenvalues are ordered (see SELECT). */
/* SELECT (external procedure) LOGICAL FUNCTION of one COMPLEX argument */
/* SELECT must be declared EXTERNAL in the calling subroutine. */
/* If SORT = 'S', SELECT is used to select eigenvalues to order */
/* to the top left of the Schur form. */
/* IF SORT = 'N', SELECT is not referenced. */
/* The eigenvalue W(j) is selected if SELECT(W(j)) is true. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA,N) */
/* On entry, the N-by-N matrix A. */
/* On exit, A has been overwritten by its Schur form T. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* SDIM (output) INTEGER */
/* If SORT = 'N', SDIM = 0. */
/* If SORT = 'S', SDIM = number of eigenvalues for which */
/* SELECT is true. */
/* W (output) COMPLEX array, dimension (N) */
/* W contains the computed eigenvalues, in the same order that */
/* they appear on the diagonal of the output Schur form T. */
/* VS (output) COMPLEX array, dimension (LDVS,N) */
/* If JOBVS = 'V', VS contains the unitary matrix Z of Schur */
/* vectors. */
/* If JOBVS = 'N', VS is not referenced. */
/* LDVS (input) INTEGER */
/* The leading dimension of the array VS. LDVS >= 1; if */
/* JOBVS = 'V', LDVS >= N. */
/* WORK (workspace/output) COMPLEX 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). */
/* For good performance, LWORK must generally be larger. */
/* 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 (N) */
/* BWORK (workspace) LOGICAL array, dimension (N) */
/* Not referenced if SORT = 'N'. */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value. */
/* > 0: if INFO = i, and i is */
/* <= N: the QR algorithm failed to compute all the */
/* eigenvalues; elements 1:ILO-1 and i+1:N of W */
/* contain those eigenvalues which have converged; */
/* if JOBVS = 'V', VS contains the matrix which */
/* reduces A to its partially converged Schur form. */
/* = N+1: the eigenvalues could not be reordered because */
/* some eigenvalues were too close to separate (the */
/* problem is very ill-conditioned); */
/* = N+2: after reordering, roundoff changed values of */
/* some complex eigenvalues so that leading */
/* eigenvalues in the Schur form no longer satisfy */
/* SELECT = .TRUE.. This could also be caused by */
/* underflow due to scaling. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. Local Arrays .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input arguments */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
vs_dim1 = *ldvs;
vs_offset = 1 + vs_dim1;
vs -= vs_offset;
--work;
--rwork;
--bwork;
/* Function Body */
*info = 0;
lquery = *lwork == -1;
wantvs = lsame_(jobvs, "V");
wantst = lsame_(sort, "S");
if (! wantvs && ! lsame_(jobvs, "N")) {
*info = -1;
} else if (! wantst && ! lsame_(sort, "N")) {
*info = -2;
} else if (*n < 0) {
*info = -4;
} else if (*lda < max(1,*n)) {
*info = -6;
} else if (*ldvs < 1 || wantvs && *ldvs < *n) {
*info = -10;
}
/* 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. */
/* CWorkspace refers to complex workspace, and RWorkspace to real */
/* workspace. NB refers to the optimal block size for the */
/* immediately following subroutine, as returned by ILAENV. */
/* HSWORK refers to the workspace preferred by CHSEQR, as */
/* calculated below. HSWORK is computed assuming ILO=1 and IHI=N, */
/* the worst case.) */
if (*info == 0) {
if (*n == 0) {
minwrk = 1;
maxwrk = 1;
} else {
maxwrk = *n + *n * ilaenv_(&c__1, "CGEHRD", " ", n, &c__1, n, &
c__0);
minwrk = *n << 1;
chseqr_("S", jobvs, n, &c__1, n, &a[a_offset], lda, &w[1], &vs[
vs_offset], ldvs, &work[1], &c_n1, &ieval);
hswork = work[1].r;
if (! wantvs) {
maxwrk = max(maxwrk,hswork);
} else {
/* Computing MAX */
i__1 = maxwrk, i__2 = *n + (*n - 1) * ilaenv_(&c__1, "CUNGHR",
" ", n, &c__1, n, &c_n1);
maxwrk = max(i__1,i__2);
maxwrk = max(maxwrk,hswork);
}
}
work[1].r = (real) maxwrk, work[1].i = 0.f;
if (*lwork < minwrk && ! lquery) {
*info = -12;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CGEES ", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
if (*n == 0) {
*sdim = 0;
return 0;
}
/* Get machine constants */
eps = slamch_("P");
smlnum = slamch_("S");
bignum = 1.f / smlnum;
slabad_(&smlnum, &bignum);
smlnum = sqrt(smlnum) / eps;
bignum = 1.f / smlnum;
/* Scale A if max element outside range [SMLNUM,BIGNUM] */
anrm = clange_("M", n, n, &a[a_offset], lda, dum);
scalea = FALSE_;
if (anrm > 0.f && anrm < smlnum) {
scalea = TRUE_;
cscale = smlnum;
} else if (anrm > bignum) {
scalea = TRUE_;
cscale = bignum;
}
if (scalea) {
clascl_("G", &c__0, &c__0, &anrm, &cscale, n, n, &a[a_offset], lda, &
ierr);
}
/* Permute the matrix to make it more nearly triangular */
/* (CWorkspace: none) */
/* (RWorkspace: need N) */
ibal = 1;
cgebal_("P", n, &a[a_offset], lda, &ilo, &ihi, &rwork[ibal], &ierr);
/* Reduce to upper Hessenberg form */
/* (CWorkspace: need 2*N, prefer N+N*NB) */
/* (RWorkspace: none) */
itau = 1;
iwrk = *n + itau;
i__1 = *lwork - iwrk + 1;
cgehrd_(n, &ilo, &ihi, &a[a_offset], lda, &work[itau], &work[iwrk], &i__1,
&ierr);
if (wantvs) {
/* Copy Householder vectors to VS */
clacpy_("L", n, n, &a[a_offset], lda, &vs[vs_offset], ldvs)
;
/* Generate unitary matrix in VS */
/* (CWorkspace: need 2*N-1, prefer N+(N-1)*NB) */
/* (RWorkspace: none) */
i__1 = *lwork - iwrk + 1;
cunghr_(n, &ilo, &ihi, &vs[vs_offset], ldvs, &work[itau], &work[iwrk],
&i__1, &ierr);
}
*sdim = 0;
/* Perform QR iteration, accumulating Schur vectors in VS if desired */
/* (CWorkspace: need 1, prefer HSWORK (see comments) ) */
/* (RWorkspace: none) */
iwrk = itau;
i__1 = *lwork - iwrk + 1;
chseqr_("S", jobvs, n, &ilo, &ihi, &a[a_offset], lda, &w[1], &vs[
vs_offset], ldvs, &work[iwrk], &i__1, &ieval);
if (ieval > 0) {
*info = ieval;
}
/* Sort eigenvalues if desired */
if (wantst && *info == 0) {
if (scalea) {
clascl_("G", &c__0, &c__0, &cscale, &anrm, n, &c__1, &w[1], n, &
ierr);
}
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
bwork[i__] = (*select)(&w[i__]);
/* L10: */
}
/* Reorder eigenvalues and transform Schur vectors */
/* (CWorkspace: none) */
/* (RWorkspace: none) */
i__1 = *lwork - iwrk + 1;
ctrsen_("N", jobvs, &bwork[1], n, &a[a_offset], lda, &vs[vs_offset],
ldvs, &w[1], sdim, &s, &sep, &work[iwrk], &i__1, &icond);
}
if (wantvs) {
/* Undo balancing */
/* (CWorkspace: none) */
/* (RWorkspace: need N) */
cgebak_("P", "R", n, &ilo, &ihi, &rwork[ibal], n, &vs[vs_offset],
ldvs, &ierr);
}
if (scalea) {
/* Undo scaling for the Schur form of A */
clascl_("U", &c__0, &c__0, &cscale, &anrm, n, n, &a[a_offset], lda, &
ierr);
i__1 = *lda + 1;
ccopy_(n, &a[a_offset], &i__1, &w[1], &c__1);
}
work[1].r = (real) maxwrk, work[1].i = 0.f;
return 0;
/* End of CGEES */
} /* cgees_ */
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