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authorshmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
committershmel1k <shmel1k@ydb.tech>2022-09-02 12:44:59 +0300
commit90d450f74722da7859d6f510a869f6c6908fd12f (patch)
tree538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/slaqr0.c
parent01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff)
downloadydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/slaqr0.c')
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diff --git a/contrib/libs/clapack/slaqr0.c b/contrib/libs/clapack/slaqr0.c
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+++ b/contrib/libs/clapack/slaqr0.c
@@ -0,0 +1,753 @@
+/* slaqr0.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__13 = 13;
+static integer c__15 = 15;
+static integer c_n1 = -1;
+static integer c__12 = 12;
+static integer c__14 = 14;
+static integer c__16 = 16;
+static logical c_false = FALSE_;
+static integer c__1 = 1;
+static integer c__3 = 3;
+
+/* Subroutine */ int slaqr0_(logical *wantt, logical *wantz, integer *n,
+ integer *ilo, integer *ihi, real *h__, integer *ldh, real *wr, real *
+ wi, integer *iloz, integer *ihiz, real *z__, integer *ldz, real *work,
+ integer *lwork, integer *info)
+{
+ /* System generated locals */
+ integer h_dim1, h_offset, z_dim1, z_offset, i__1, i__2, i__3, i__4, i__5;
+ real r__1, r__2, r__3, r__4;
+
+ /* Local variables */
+ integer i__, k;
+ real aa, bb, cc, dd;
+ integer ld;
+ real cs;
+ integer nh, it, ks, kt;
+ real sn;
+ integer ku, kv, ls, ns;
+ real ss;
+ integer nw, inf, kdu, nho, nve, kwh, nsr, nwr, kwv, ndec, ndfl, kbot,
+ nmin;
+ real swap;
+ integer ktop;
+ real zdum[1] /* was [1][1] */;
+ integer kacc22, itmax, nsmax, nwmax, kwtop;
+ extern /* Subroutine */ int slanv2_(real *, real *, real *, real *, real *
+, real *, real *, real *, real *, real *), slaqr3_(logical *,
+ logical *, integer *, integer *, integer *, integer *, real *,
+ integer *, integer *, integer *, real *, integer *, integer *,
+ integer *, real *, real *, real *, integer *, integer *, real *,
+ integer *, integer *, real *, integer *, real *, integer *),
+ slaqr4_(logical *, logical *, integer *, integer *, integer *,
+ real *, integer *, real *, real *, integer *, integer *, real *,
+ integer *, real *, integer *, integer *), slaqr5_(logical *,
+ logical *, integer *, integer *, integer *, integer *, integer *,
+ real *, real *, real *, integer *, integer *, integer *, real *,
+ integer *, real *, integer *, real *, integer *, integer *, real *
+, integer *, integer *, real *, integer *);
+ integer nibble;
+ extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
+ integer *, integer *);
+ char jbcmpz[1];
+ extern /* Subroutine */ int slahqr_(logical *, logical *, integer *,
+ integer *, integer *, real *, integer *, real *, real *, integer *
+, integer *, real *, integer *, integer *), slacpy_(char *,
+ integer *, integer *, real *, integer *, real *, integer *);
+ integer nwupbd;
+ logical sorted;
+ integer lwkopt;
+
+
+/* -- LAPACK auxiliary routine (version 3.2) -- */
+/* Univ. of Tennessee, Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd.. */
+/* November 2006 */
+
+/* .. Scalar Arguments .. */
+/* .. */
+/* .. Array Arguments .. */
+/* .. */
+
+/* Purpose */
+/* ======= */
+
+/* SLAQR0 computes the eigenvalues of a Hessenberg matrix H */
+/* and, optionally, the matrices T and Z from the Schur decomposition */
+/* H = Z T Z**T, where T is an upper quasi-triangular matrix (the */
+/* Schur form), and Z is the orthogonal matrix of Schur vectors. */
+
+/* Optionally Z may be postmultiplied into an input orthogonal */
+/* matrix Q so that this routine can give the Schur factorization */
+/* of a matrix A which has been reduced to the Hessenberg form H */
+/* by the orthogonal matrix Q: A = Q*H*Q**T = (QZ)*T*(QZ)**T. */
+
+/* Arguments */
+/* ========= */
+
+/* WANTT (input) LOGICAL */
+/* = .TRUE. : the full Schur form T is required; */
+/* = .FALSE.: only eigenvalues are required. */
+
+/* WANTZ (input) LOGICAL */
+/* = .TRUE. : the matrix of Schur vectors Z is required; */
+/* = .FALSE.: Schur vectors are not required. */
+
+/* N (input) INTEGER */
+/* The order of the matrix H. N .GE. 0. */
+
+/* ILO (input) INTEGER */
+/* IHI (input) INTEGER */
+/* It is assumed that H is already upper triangular in rows */
+/* and columns 1:ILO-1 and IHI+1:N and, if ILO.GT.1, */
+/* H(ILO,ILO-1) is zero. ILO and IHI are normally set by a */
+/* previous call to SGEBAL, and then passed to SGEHRD when the */
+/* matrix output by SGEBAL is reduced to Hessenberg form. */
+/* Otherwise, ILO and IHI should be set to 1 and N, */
+/* respectively. If N.GT.0, then 1.LE.ILO.LE.IHI.LE.N. */
+/* If N = 0, then ILO = 1 and IHI = 0. */
+
+/* H (input/output) REAL array, dimension (LDH,N) */
+/* On entry, the upper Hessenberg matrix H. */
+/* On exit, if INFO = 0 and WANTT is .TRUE., then H contains */
+/* the upper quasi-triangular matrix T from the Schur */
+/* decomposition (the Schur form); 2-by-2 diagonal blocks */
+/* (corresponding to complex conjugate pairs of eigenvalues) */
+/* are returned in standard form, with H(i,i) = H(i+1,i+1) */
+/* and H(i+1,i)*H(i,i+1).LT.0. If INFO = 0 and WANTT is */
+/* .FALSE., then the contents of H are unspecified on exit. */
+/* (The output value of H when INFO.GT.0 is given under the */
+/* description of INFO below.) */
+
+/* This subroutine may explicitly set H(i,j) = 0 for i.GT.j and */
+/* j = 1, 2, ... ILO-1 or j = IHI+1, IHI+2, ... N. */
+
+/* LDH (input) INTEGER */
+/* The leading dimension of the array H. LDH .GE. max(1,N). */
+
+/* WR (output) REAL array, dimension (IHI) */
+/* WI (output) REAL array, dimension (IHI) */
+/* The real and imaginary parts, respectively, of the computed */
+/* eigenvalues of H(ILO:IHI,ILO:IHI) are stored in WR(ILO:IHI) */
+/* and WI(ILO:IHI). If two eigenvalues are computed as a */
+/* complex conjugate pair, they are stored in consecutive */
+/* elements of WR and WI, say the i-th and (i+1)th, with */
+/* WI(i) .GT. 0 and WI(i+1) .LT. 0. If WANTT is .TRUE., then */
+/* the eigenvalues are stored in the same order as on the */
+/* diagonal of the Schur form returned in H, with */
+/* WR(i) = H(i,i) and, if H(i:i+1,i:i+1) is a 2-by-2 diagonal */
+/* block, WI(i) = sqrt(-H(i+1,i)*H(i,i+1)) and */
+/* WI(i+1) = -WI(i). */
+
+/* ILOZ (input) INTEGER */
+/* IHIZ (input) INTEGER */
+/* Specify the rows of Z to which transformations must be */
+/* applied if WANTZ is .TRUE.. */
+/* 1 .LE. ILOZ .LE. ILO; IHI .LE. IHIZ .LE. N. */
+
+/* Z (input/output) REAL array, dimension (LDZ,IHI) */
+/* If WANTZ is .FALSE., then Z is not referenced. */
+/* If WANTZ is .TRUE., then Z(ILO:IHI,ILOZ:IHIZ) is */
+/* replaced by Z(ILO:IHI,ILOZ:IHIZ)*U where U is the */
+/* orthogonal Schur factor of H(ILO:IHI,ILO:IHI). */
+/* (The output value of Z when INFO.GT.0 is given under */
+/* the description of INFO below.) */
+
+/* LDZ (input) INTEGER */
+/* The leading dimension of the array Z. if WANTZ is .TRUE. */
+/* then LDZ.GE.MAX(1,IHIZ). Otherwize, LDZ.GE.1. */
+
+/* WORK (workspace/output) REAL array, dimension LWORK */
+/* On exit, if LWORK = -1, WORK(1) returns an estimate of */
+/* the optimal value for LWORK. */
+
+/* LWORK (input) INTEGER */
+/* The dimension of the array WORK. LWORK .GE. max(1,N) */
+/* is sufficient, but LWORK typically as large as 6*N may */
+/* be required for optimal performance. A workspace query */
+/* to determine the optimal workspace size is recommended. */
+
+/* If LWORK = -1, then SLAQR0 does a workspace query. */
+/* In this case, SLAQR0 checks the input parameters and */
+/* estimates the optimal workspace size for the given */
+/* values of N, ILO and IHI. The estimate is returned */
+/* in WORK(1). No error message related to LWORK is */
+/* issued by XERBLA. Neither H nor Z are accessed. */
+
+
+/* INFO (output) INTEGER */
+/* = 0: successful exit */
+/* .GT. 0: if INFO = i, SLAQR0 failed to compute all of */
+/* the eigenvalues. Elements 1:ilo-1 and i+1:n of WR */
+/* and WI contain those eigenvalues which have been */
+/* successfully computed. (Failures are rare.) */
+
+/* If INFO .GT. 0 and WANT is .FALSE., then on exit, */
+/* the remaining unconverged eigenvalues are the eigen- */
+/* values of the upper Hessenberg matrix rows and */
+/* columns ILO through INFO of the final, output */
+/* value of H. */
+
+/* If INFO .GT. 0 and WANTT is .TRUE., then on exit */
+
+/* (*) (initial value of H)*U = U*(final value of H) */
+
+/* where U is an orthogonal matrix. The final */
+/* value of H is upper Hessenberg and quasi-triangular */
+/* in rows and columns INFO+1 through IHI. */
+
+/* If INFO .GT. 0 and WANTZ is .TRUE., then on exit */
+
+/* (final value of Z(ILO:IHI,ILOZ:IHIZ) */
+/* = (initial value of Z(ILO:IHI,ILOZ:IHIZ)*U */
+
+/* where U is the orthogonal matrix in (*) (regard- */
+/* less of the value of WANTT.) */
+
+/* If INFO .GT. 0 and WANTZ is .FALSE., then Z is not */
+/* accessed. */
+
+/* ================================================================ */
+/* Based on contributions by */
+/* Karen Braman and Ralph Byers, Department of Mathematics, */
+/* University of Kansas, USA */
+
+/* ================================================================ */
+/* References: */
+/* K. Braman, R. Byers and R. Mathias, The Multi-Shift QR */
+/* Algorithm Part I: Maintaining Well Focused Shifts, and Level 3 */
+/* Performance, SIAM Journal of Matrix Analysis, volume 23, pages */
+/* 929--947, 2002. */
+
+/* K. Braman, R. Byers and R. Mathias, The Multi-Shift QR */
+/* Algorithm Part II: Aggressive Early Deflation, SIAM Journal */
+/* of Matrix Analysis, volume 23, pages 948--973, 2002. */
+
+/* ================================================================ */
+/* .. Parameters .. */
+
+/* ==== Matrices of order NTINY or smaller must be processed by */
+/* . SLAHQR because of insufficient subdiagonal scratch space. */
+/* . (This is a hard limit.) ==== */
+
+/* ==== Exceptional deflation windows: try to cure rare */
+/* . slow convergence by varying the size of the */
+/* . deflation window after KEXNW iterations. ==== */
+
+/* ==== Exceptional shifts: try to cure rare slow convergence */
+/* . with ad-hoc exceptional shifts every KEXSH iterations. */
+/* . ==== */
+
+/* ==== The constants WILK1 and WILK2 are used to form the */
+/* . exceptional shifts. ==== */
+/* .. */
+/* .. Local Scalars .. */
+/* .. */
+/* .. External Functions .. */
+/* .. */
+/* .. Local Arrays .. */
+/* .. */
+/* .. External Subroutines .. */
+/* .. */
+/* .. Intrinsic Functions .. */
+/* .. */
+/* .. Executable Statements .. */
+ /* Parameter adjustments */
+ h_dim1 = *ldh;
+ h_offset = 1 + h_dim1;
+ h__ -= h_offset;
+ --wr;
+ --wi;
+ z_dim1 = *ldz;
+ z_offset = 1 + z_dim1;
+ z__ -= z_offset;
+ --work;
+
+ /* Function Body */
+ *info = 0;
+
+/* ==== Quick return for N = 0: nothing to do. ==== */
+
+ if (*n == 0) {
+ work[1] = 1.f;
+ return 0;
+ }
+
+ if (*n <= 11) {
+
+/* ==== Tiny matrices must use SLAHQR. ==== */
+
+ lwkopt = 1;
+ if (*lwork != -1) {
+ slahqr_(wantt, wantz, n, ilo, ihi, &h__[h_offset], ldh, &wr[1], &
+ wi[1], iloz, ihiz, &z__[z_offset], ldz, info);
+ }
+ } else {
+
+/* ==== Use small bulge multi-shift QR with aggressive early */
+/* . deflation on larger-than-tiny matrices. ==== */
+
+/* ==== Hope for the best. ==== */
+
+ *info = 0;
+
+/* ==== Set up job flags for ILAENV. ==== */
+
+ if (*wantt) {
+ *(unsigned char *)jbcmpz = 'S';
+ } else {
+ *(unsigned char *)jbcmpz = 'E';
+ }
+ if (*wantz) {
+ *(unsigned char *)&jbcmpz[1] = 'V';
+ } else {
+ *(unsigned char *)&jbcmpz[1] = 'N';
+ }
+
+/* ==== NWR = recommended deflation window size. At this */
+/* . point, N .GT. NTINY = 11, so there is enough */
+/* . subdiagonal workspace for NWR.GE.2 as required. */
+/* . (In fact, there is enough subdiagonal space for */
+/* . NWR.GE.3.) ==== */
+
+ nwr = ilaenv_(&c__13, "SLAQR0", jbcmpz, n, ilo, ihi, lwork);
+ nwr = max(2,nwr);
+/* Computing MIN */
+ i__1 = *ihi - *ilo + 1, i__2 = (*n - 1) / 3, i__1 = min(i__1,i__2);
+ nwr = min(i__1,nwr);
+
+/* ==== NSR = recommended number of simultaneous shifts. */
+/* . At this point N .GT. NTINY = 11, so there is at */
+/* . enough subdiagonal workspace for NSR to be even */
+/* . and greater than or equal to two as required. ==== */
+
+ nsr = ilaenv_(&c__15, "SLAQR0", jbcmpz, n, ilo, ihi, lwork);
+/* Computing MIN */
+ i__1 = nsr, i__2 = (*n + 6) / 9, i__1 = min(i__1,i__2), i__2 = *ihi -
+ *ilo;
+ nsr = min(i__1,i__2);
+/* Computing MAX */
+ i__1 = 2, i__2 = nsr - nsr % 2;
+ nsr = max(i__1,i__2);
+
+/* ==== Estimate optimal workspace ==== */
+
+/* ==== Workspace query call to SLAQR3 ==== */
+
+ i__1 = nwr + 1;
+ slaqr3_(wantt, wantz, n, ilo, ihi, &i__1, &h__[h_offset], ldh, iloz,
+ ihiz, &z__[z_offset], ldz, &ls, &ld, &wr[1], &wi[1], &h__[
+ h_offset], ldh, n, &h__[h_offset], ldh, n, &h__[h_offset],
+ ldh, &work[1], &c_n1);
+
+/* ==== Optimal workspace = MAX(SLAQR5, SLAQR3) ==== */
+
+/* Computing MAX */
+ i__1 = nsr * 3 / 2, i__2 = (integer) work[1];
+ lwkopt = max(i__1,i__2);
+
+/* ==== Quick return in case of workspace query. ==== */
+
+ if (*lwork == -1) {
+ work[1] = (real) lwkopt;
+ return 0;
+ }
+
+/* ==== SLAHQR/SLAQR0 crossover point ==== */
+
+ nmin = ilaenv_(&c__12, "SLAQR0", jbcmpz, n, ilo, ihi, lwork);
+ nmin = max(11,nmin);
+
+/* ==== Nibble crossover point ==== */
+
+ nibble = ilaenv_(&c__14, "SLAQR0", jbcmpz, n, ilo, ihi, lwork);
+ nibble = max(0,nibble);
+
+/* ==== Accumulate reflections during ttswp? Use block */
+/* . 2-by-2 structure during matrix-matrix multiply? ==== */
+
+ kacc22 = ilaenv_(&c__16, "SLAQR0", jbcmpz, n, ilo, ihi, lwork);
+ kacc22 = max(0,kacc22);
+ kacc22 = min(2,kacc22);
+
+/* ==== NWMAX = the largest possible deflation window for */
+/* . which there is sufficient workspace. ==== */
+
+/* Computing MIN */
+ i__1 = (*n - 1) / 3, i__2 = *lwork / 2;
+ nwmax = min(i__1,i__2);
+ nw = nwmax;
+
+/* ==== NSMAX = the Largest number of simultaneous shifts */
+/* . for which there is sufficient workspace. ==== */
+
+/* Computing MIN */
+ i__1 = (*n + 6) / 9, i__2 = (*lwork << 1) / 3;
+ nsmax = min(i__1,i__2);
+ nsmax -= nsmax % 2;
+
+/* ==== NDFL: an iteration count restarted at deflation. ==== */
+
+ ndfl = 1;
+
+/* ==== ITMAX = iteration limit ==== */
+
+/* Computing MAX */
+ i__1 = 10, i__2 = *ihi - *ilo + 1;
+ itmax = max(i__1,i__2) * 30;
+
+/* ==== Last row and column in the active block ==== */
+
+ kbot = *ihi;
+
+/* ==== Main Loop ==== */
+
+ i__1 = itmax;
+ for (it = 1; it <= i__1; ++it) {
+
+/* ==== Done when KBOT falls below ILO ==== */
+
+ if (kbot < *ilo) {
+ goto L90;
+ }
+
+/* ==== Locate active block ==== */
+
+ i__2 = *ilo + 1;
+ for (k = kbot; k >= i__2; --k) {
+ if (h__[k + (k - 1) * h_dim1] == 0.f) {
+ goto L20;
+ }
+/* L10: */
+ }
+ k = *ilo;
+L20:
+ ktop = k;
+
+/* ==== Select deflation window size: */
+/* . Typical Case: */
+/* . If possible and advisable, nibble the entire */
+/* . active block. If not, use size MIN(NWR,NWMAX) */
+/* . or MIN(NWR+1,NWMAX) depending upon which has */
+/* . the smaller corresponding subdiagonal entry */
+/* . (a heuristic). */
+/* . */
+/* . Exceptional Case: */
+/* . If there have been no deflations in KEXNW or */
+/* . more iterations, then vary the deflation window */
+/* . size. At first, because, larger windows are, */
+/* . in general, more powerful than smaller ones, */
+/* . rapidly increase the window to the maximum possible. */
+/* . Then, gradually reduce the window size. ==== */
+
+ nh = kbot - ktop + 1;
+ nwupbd = min(nh,nwmax);
+ if (ndfl < 5) {
+ nw = min(nwupbd,nwr);
+ } else {
+/* Computing MIN */
+ i__2 = nwupbd, i__3 = nw << 1;
+ nw = min(i__2,i__3);
+ }
+ if (nw < nwmax) {
+ if (nw >= nh - 1) {
+ nw = nh;
+ } else {
+ kwtop = kbot - nw + 1;
+ if ((r__1 = h__[kwtop + (kwtop - 1) * h_dim1], dabs(r__1))
+ > (r__2 = h__[kwtop - 1 + (kwtop - 2) * h_dim1],
+ dabs(r__2))) {
+ ++nw;
+ }
+ }
+ }
+ if (ndfl < 5) {
+ ndec = -1;
+ } else if (ndec >= 0 || nw >= nwupbd) {
+ ++ndec;
+ if (nw - ndec < 2) {
+ ndec = 0;
+ }
+ nw -= ndec;
+ }
+
+/* ==== Aggressive early deflation: */
+/* . split workspace under the subdiagonal into */
+/* . - an nw-by-nw work array V in the lower */
+/* . left-hand-corner, */
+/* . - an NW-by-at-least-NW-but-more-is-better */
+/* . (NW-by-NHO) horizontal work array along */
+/* . the bottom edge, */
+/* . - an at-least-NW-but-more-is-better (NHV-by-NW) */
+/* . vertical work array along the left-hand-edge. */
+/* . ==== */
+
+ kv = *n - nw + 1;
+ kt = nw + 1;
+ nho = *n - nw - 1 - kt + 1;
+ kwv = nw + 2;
+ nve = *n - nw - kwv + 1;
+
+/* ==== Aggressive early deflation ==== */
+
+ slaqr3_(wantt, wantz, n, &ktop, &kbot, &nw, &h__[h_offset], ldh,
+ iloz, ihiz, &z__[z_offset], ldz, &ls, &ld, &wr[1], &wi[1],
+ &h__[kv + h_dim1], ldh, &nho, &h__[kv + kt * h_dim1],
+ ldh, &nve, &h__[kwv + h_dim1], ldh, &work[1], lwork);
+
+/* ==== Adjust KBOT accounting for new deflations. ==== */
+
+ kbot -= ld;
+
+/* ==== KS points to the shifts. ==== */
+
+ ks = kbot - ls + 1;
+
+/* ==== Skip an expensive QR sweep if there is a (partly */
+/* . heuristic) reason to expect that many eigenvalues */
+/* . will deflate without it. Here, the QR sweep is */
+/* . skipped if many eigenvalues have just been deflated */
+/* . or if the remaining active block is small. */
+
+ if (ld == 0 || ld * 100 <= nw * nibble && kbot - ktop + 1 > min(
+ nmin,nwmax)) {
+
+/* ==== NS = nominal number of simultaneous shifts. */
+/* . This may be lowered (slightly) if SLAQR3 */
+/* . did not provide that many shifts. ==== */
+
+/* Computing MIN */
+/* Computing MAX */
+ i__4 = 2, i__5 = kbot - ktop;
+ i__2 = min(nsmax,nsr), i__3 = max(i__4,i__5);
+ ns = min(i__2,i__3);
+ ns -= ns % 2;
+
+/* ==== If there have been no deflations */
+/* . in a multiple of KEXSH iterations, */
+/* . then try exceptional shifts. */
+/* . Otherwise use shifts provided by */
+/* . SLAQR3 above or from the eigenvalues */
+/* . of a trailing principal submatrix. ==== */
+
+ if (ndfl % 6 == 0) {
+ ks = kbot - ns + 1;
+/* Computing MAX */
+ i__3 = ks + 1, i__4 = ktop + 2;
+ i__2 = max(i__3,i__4);
+ for (i__ = kbot; i__ >= i__2; i__ += -2) {
+ ss = (r__1 = h__[i__ + (i__ - 1) * h_dim1], dabs(r__1)
+ ) + (r__2 = h__[i__ - 1 + (i__ - 2) * h_dim1],
+ dabs(r__2));
+ aa = ss * .75f + h__[i__ + i__ * h_dim1];
+ bb = ss;
+ cc = ss * -.4375f;
+ dd = aa;
+ slanv2_(&aa, &bb, &cc, &dd, &wr[i__ - 1], &wi[i__ - 1]
+, &wr[i__], &wi[i__], &cs, &sn);
+/* L30: */
+ }
+ if (ks == ktop) {
+ wr[ks + 1] = h__[ks + 1 + (ks + 1) * h_dim1];
+ wi[ks + 1] = 0.f;
+ wr[ks] = wr[ks + 1];
+ wi[ks] = wi[ks + 1];
+ }
+ } else {
+
+/* ==== Got NS/2 or fewer shifts? Use SLAQR4 or */
+/* . SLAHQR on a trailing principal submatrix to */
+/* . get more. (Since NS.LE.NSMAX.LE.(N+6)/9, */
+/* . there is enough space below the subdiagonal */
+/* . to fit an NS-by-NS scratch array.) ==== */
+
+ if (kbot - ks + 1 <= ns / 2) {
+ ks = kbot - ns + 1;
+ kt = *n - ns + 1;
+ slacpy_("A", &ns, &ns, &h__[ks + ks * h_dim1], ldh, &
+ h__[kt + h_dim1], ldh);
+ if (ns > nmin) {
+ slaqr4_(&c_false, &c_false, &ns, &c__1, &ns, &h__[
+ kt + h_dim1], ldh, &wr[ks], &wi[ks], &
+ c__1, &c__1, zdum, &c__1, &work[1], lwork,
+ &inf);
+ } else {
+ slahqr_(&c_false, &c_false, &ns, &c__1, &ns, &h__[
+ kt + h_dim1], ldh, &wr[ks], &wi[ks], &
+ c__1, &c__1, zdum, &c__1, &inf);
+ }
+ ks += inf;
+
+/* ==== In case of a rare QR failure use */
+/* . eigenvalues of the trailing 2-by-2 */
+/* . principal submatrix. ==== */
+
+ if (ks >= kbot) {
+ aa = h__[kbot - 1 + (kbot - 1) * h_dim1];
+ cc = h__[kbot + (kbot - 1) * h_dim1];
+ bb = h__[kbot - 1 + kbot * h_dim1];
+ dd = h__[kbot + kbot * h_dim1];
+ slanv2_(&aa, &bb, &cc, &dd, &wr[kbot - 1], &wi[
+ kbot - 1], &wr[kbot], &wi[kbot], &cs, &sn)
+ ;
+ ks = kbot - 1;
+ }
+ }
+
+ if (kbot - ks + 1 > ns) {
+
+/* ==== Sort the shifts (Helps a little) */
+/* . Bubble sort keeps complex conjugate */
+/* . pairs together. ==== */
+
+ sorted = FALSE_;
+ i__2 = ks + 1;
+ for (k = kbot; k >= i__2; --k) {
+ if (sorted) {
+ goto L60;
+ }
+ sorted = TRUE_;
+ i__3 = k - 1;
+ for (i__ = ks; i__ <= i__3; ++i__) {
+ if ((r__1 = wr[i__], dabs(r__1)) + (r__2 = wi[
+ i__], dabs(r__2)) < (r__3 = wr[i__ +
+ 1], dabs(r__3)) + (r__4 = wi[i__ + 1],
+ dabs(r__4))) {
+ sorted = FALSE_;
+
+ swap = wr[i__];
+ wr[i__] = wr[i__ + 1];
+ wr[i__ + 1] = swap;
+
+ swap = wi[i__];
+ wi[i__] = wi[i__ + 1];
+ wi[i__ + 1] = swap;
+ }
+/* L40: */
+ }
+/* L50: */
+ }
+L60:
+ ;
+ }
+
+/* ==== Shuffle shifts into pairs of real shifts */
+/* . and pairs of complex conjugate shifts */
+/* . assuming complex conjugate shifts are */
+/* . already adjacent to one another. (Yes, */
+/* . they are.) ==== */
+
+ i__2 = ks + 2;
+ for (i__ = kbot; i__ >= i__2; i__ += -2) {
+ if (wi[i__] != -wi[i__ - 1]) {
+
+ swap = wr[i__];
+ wr[i__] = wr[i__ - 1];
+ wr[i__ - 1] = wr[i__ - 2];
+ wr[i__ - 2] = swap;
+
+ swap = wi[i__];
+ wi[i__] = wi[i__ - 1];
+ wi[i__ - 1] = wi[i__ - 2];
+ wi[i__ - 2] = swap;
+ }
+/* L70: */
+ }
+ }
+
+/* ==== If there are only two shifts and both are */
+/* . real, then use only one. ==== */
+
+ if (kbot - ks + 1 == 2) {
+ if (wi[kbot] == 0.f) {
+ if ((r__1 = wr[kbot] - h__[kbot + kbot * h_dim1],
+ dabs(r__1)) < (r__2 = wr[kbot - 1] - h__[kbot
+ + kbot * h_dim1], dabs(r__2))) {
+ wr[kbot - 1] = wr[kbot];
+ } else {
+ wr[kbot] = wr[kbot - 1];
+ }
+ }
+ }
+
+/* ==== Use up to NS of the the smallest magnatiude */
+/* . shifts. If there aren't NS shifts available, */
+/* . then use them all, possibly dropping one to */
+/* . make the number of shifts even. ==== */
+
+/* Computing MIN */
+ i__2 = ns, i__3 = kbot - ks + 1;
+ ns = min(i__2,i__3);
+ ns -= ns % 2;
+ ks = kbot - ns + 1;
+
+/* ==== Small-bulge multi-shift QR sweep: */
+/* . split workspace under the subdiagonal into */
+/* . - a KDU-by-KDU work array U in the lower */
+/* . left-hand-corner, */
+/* . - a KDU-by-at-least-KDU-but-more-is-better */
+/* . (KDU-by-NHo) horizontal work array WH along */
+/* . the bottom edge, */
+/* . - and an at-least-KDU-but-more-is-better-by-KDU */
+/* . (NVE-by-KDU) vertical work WV arrow along */
+/* . the left-hand-edge. ==== */
+
+ kdu = ns * 3 - 3;
+ ku = *n - kdu + 1;
+ kwh = kdu + 1;
+ nho = *n - kdu - 3 - (kdu + 1) + 1;
+ kwv = kdu + 4;
+ nve = *n - kdu - kwv + 1;
+
+/* ==== Small-bulge multi-shift QR sweep ==== */
+
+ slaqr5_(wantt, wantz, &kacc22, n, &ktop, &kbot, &ns, &wr[ks],
+ &wi[ks], &h__[h_offset], ldh, iloz, ihiz, &z__[
+ z_offset], ldz, &work[1], &c__3, &h__[ku + h_dim1],
+ ldh, &nve, &h__[kwv + h_dim1], ldh, &nho, &h__[ku +
+ kwh * h_dim1], ldh);
+ }
+
+/* ==== Note progress (or the lack of it). ==== */
+
+ if (ld > 0) {
+ ndfl = 1;
+ } else {
+ ++ndfl;
+ }
+
+/* ==== End of main loop ==== */
+/* L80: */
+ }
+
+/* ==== Iteration limit exceeded. Set INFO to show where */
+/* . the problem occurred and exit. ==== */
+
+ *info = kbot;
+L90:
+ ;
+ }
+
+/* ==== Return the optimal value of LWORK. ==== */
+
+ work[1] = (real) lwkopt;
+
+/* ==== End of SLAQR0 ==== */
+
+ return 0;
+} /* slaqr0_ */