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author | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
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committer | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
commit | 90d450f74722da7859d6f510a869f6c6908fd12f (patch) | |
tree | 538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/slaqr0.c | |
parent | 01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff) | |
download | ydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz |
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/slaqr0.c')
-rw-r--r-- | contrib/libs/clapack/slaqr0.c | 753 |
1 files changed, 753 insertions, 0 deletions
diff --git a/contrib/libs/clapack/slaqr0.c b/contrib/libs/clapack/slaqr0.c new file mode 100644 index 0000000000..d2dab03045 --- /dev/null +++ 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_ */ |