/* sgsvj1.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 real c_b35 = 1.f;
/* Subroutine */ int sgsvj1_(char *jobv, integer *m, integer *n, integer *n1,
real *a, integer *lda, real *d__, real *sva, integer *mv, real *v,
integer *ldv, real *eps, real *sfmin, real *tol, integer *nsweep,
real *work, integer *lwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, v_dim1, v_offset, i__1, i__2, i__3, i__4, i__5,
i__6;
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal), r_sign(real *, real *);
/* Local variables */
real bigtheta;
integer pskipped, i__, p, q;
real t, rootsfmin, cs, sn;
integer jbc;
real big;
integer kbl, igl, ibr, jgl, mvl, nblc;
real aapp, aapq, aaqq;
integer nblr, ierr;
extern doublereal sdot_(integer *, real *, integer *, real *, integer *);
real aapp0, temp1;
extern doublereal snrm2_(integer *, real *, integer *);
real large, apoaq, aqoap;
extern logical lsame_(char *, char *);
real theta, small, fastr[5];
logical applv, rsvec;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *);
logical rotok;
extern /* Subroutine */ int sswap_(integer *, real *, integer *, real *,
integer *), saxpy_(integer *, real *, real *, integer *, real *,
integer *), srotm_(integer *, real *, integer *, real *, integer *
, real *), xerbla_(char *, integer *);
integer ijblsk, swband;
extern /* Subroutine */ int slascl_(char *, integer *, integer *, real *,
real *, integer *, integer *, real *, integer *, integer *);
extern integer isamax_(integer *, real *, integer *);
integer blskip;
real mxaapq, thsign;
extern /* Subroutine */ int slassq_(integer *, real *, integer *, real *,
real *);
real mxsinj;
integer emptsw, notrot, iswrot;
real rootbig, rooteps;
integer rowskip;
real roottol;
/* -- LAPACK routine (version 3.2) -- */
/* -- Contributed by Zlatko Drmac of the University of Zagreb and -- */
/* -- Kresimir Veselic of the Fernuniversitaet Hagen -- */
/* -- November 2008 -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* This routine is also part of SIGMA (version 1.23, October 23. 2008.) */
/* SIGMA is a library of algorithms for highly accurate algorithms for */
/* computation of SVD, PSVD, QSVD, (H,K)-SVD, and for solution of the */
/* eigenvalue problems Hx = lambda M x, H M x = lambda x with H, M > 0. */
/* -#- Scalar Arguments -#- */
/* -#- Array Arguments -#- */
/* .. */
/* Purpose */
/* ~~~~~~~ */
/* SGSVJ1 is called from SGESVJ as a pre-processor and that is its main */
/* purpose. It applies Jacobi rotations in the same way as SGESVJ does, but */
/* it targets only particular pivots and it does not check convergence */
/* (stopping criterion). Few tunning parameters (marked by [TP]) are */
/* available for the implementer. */
/* Further details */
/* ~~~~~~~~~~~~~~~ */
/* SGSVJ1 applies few sweeps of Jacobi rotations in the column space of */
/* the input M-by-N matrix A. The pivot pairs are taken from the (1,2) */
/* off-diagonal block in the corresponding N-by-N Gram matrix A^T * A. The */
/* block-entries (tiles) of the (1,2) off-diagonal block are marked by the */
/* [x]'s in the following scheme: */
/* | * * * [x] [x] [x]| */
/* | * * * [x] [x] [x]| Row-cycling in the nblr-by-nblc [x] blocks. */
/* | * * * [x] [x] [x]| Row-cyclic pivoting inside each [x] block. */
/* |[x] [x] [x] * * * | */
/* |[x] [x] [x] * * * | */
/* |[x] [x] [x] * * * | */
/* In terms of the columns of A, the first N1 columns are rotated 'against' */
/* the remaining N-N1 columns, trying to increase the angle between the */
/* corresponding subspaces. The off-diagonal block is N1-by(N-N1) and it is */
/* tiled using quadratic tiles of side KBL. Here, KBL is a tunning parmeter. */
/* The number of sweeps is given in NSWEEP and the orthogonality threshold */
/* is given in TOL. */
/* Contributors */
/* ~~~~~~~~~~~~ */
/* Zlatko Drmac (Zagreb, Croatia) and Kresimir Veselic (Hagen, Germany) */
/* Arguments */
/* ~~~~~~~~~ */
/* JOBV (input) CHARACTER*1 */
/* Specifies whether the output from this procedure is used */
/* to compute the matrix V: */
/* = 'V': the product of the Jacobi rotations is accumulated */
/* by postmulyiplying the N-by-N array V. */
/* (See the description of V.) */
/* = 'A': the product of the Jacobi rotations is accumulated */
/* by postmulyiplying the MV-by-N array V. */
/* (See the descriptions of MV and V.) */
/* = 'N': the Jacobi rotations are not accumulated. */
/* M (input) INTEGER */
/* The number of rows of the input matrix A. M >= 0. */
/* N (input) INTEGER */
/* The number of columns of the input matrix A. */
/* M >= N >= 0. */
/* N1 (input) INTEGER */
/* N1 specifies the 2 x 2 block partition, the first N1 columns are */
/* rotated 'against' the remaining N-N1 columns of A. */
/* A (input/output) REAL array, dimension (LDA,N) */
/* On entry, M-by-N matrix A, such that A*diag(D) represents */
/* the input matrix. */
/* On exit, */
/* A_onexit * D_onexit represents the input matrix A*diag(D) */
/* post-multiplied by a sequence of Jacobi rotations, where the */
/* rotation threshold and the total number of sweeps are given in */
/* TOL and NSWEEP, respectively. */
/* (See the descriptions of N1, D, TOL and NSWEEP.) */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,M). */
/* D (input/workspace/output) REAL array, dimension (N) */
/* The array D accumulates the scaling factors from the fast scaled */
/* Jacobi rotations. */
/* On entry, A*diag(D) represents the input matrix. */
/* On exit, A_onexit*diag(D_onexit) represents the input matrix */
/* post-multiplied by a sequence of Jacobi rotations, where the */
/* rotation threshold and the total number of sweeps are given in */
/* TOL and NSWEEP, respectively. */
/* (See the descriptions of N1, A, TOL and NSWEEP.) */
/* SVA (input/workspace/output) REAL array, dimension (N) */
/* On entry, SVA contains the Euclidean norms of the columns of */
/* the matrix A*diag(D). */
/* On exit, SVA contains the Euclidean norms of the columns of */
/* the matrix onexit*diag(D_onexit). */
/* MV (input) INTEGER */
/* If JOBV .EQ. 'A', then MV rows of V are post-multipled by a */
/* sequence of Jacobi rotations. */
/* If JOBV = 'N', then MV is not referenced. */
/* V (input/output) REAL array, dimension (LDV,N) */
/* If JOBV .EQ. 'V' then N rows of V are post-multipled by a */
/* sequence of Jacobi rotations. */
/* If JOBV .EQ. 'A' then MV rows of V are post-multipled by a */
/* sequence of Jacobi rotations. */
/* If JOBV = 'N', then V is not referenced. */
/* LDV (input) INTEGER */
/* The leading dimension of the array V, LDV >= 1. */
/* If JOBV = 'V', LDV .GE. N. */
/* If JOBV = 'A', LDV .GE. MV. */
/* EPS (input) INTEGER */
/* EPS = SLAMCH('Epsilon') */
/* SFMIN (input) INTEGER */
/* SFMIN = SLAMCH('Safe Minimum') */
/* TOL (input) REAL */
/* TOL is the threshold for Jacobi rotations. For a pair */
/* A(:,p), A(:,q) of pivot columns, the Jacobi rotation is */
/* applied only if ABS(COS(angle(A(:,p),A(:,q)))) .GT. TOL. */
/* NSWEEP (input) INTEGER */
/* NSWEEP is the number of sweeps of Jacobi rotations to be */
/* performed. */
/* WORK (workspace) REAL array, dimension LWORK. */
/* LWORK (input) INTEGER */
/* LWORK is the dimension of WORK. LWORK .GE. M. */
/* INFO (output) INTEGER */
/* = 0 : successful exit. */
/* < 0 : if INFO = -i, then the i-th argument had an illegal value */
/* -#- Local Parameters -#- */
/* -#- Local Scalars -#- */
/* Local Arrays */
/* Intrinsic Functions */
/* External Functions */
/* External Subroutines */
/* Parameter adjustments */
--sva;
--d__;
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
v_dim1 = *ldv;
v_offset = 1 + v_dim1;
v -= v_offset;
--work;
/* Function Body */
applv = lsame_(jobv, "A");
rsvec = lsame_(jobv, "V");
if (! (rsvec || applv || lsame_(jobv, "N"))) {
*info = -1;
} else if (*m < 0) {
*info = -2;
} else if (*n < 0 || *n > *m) {
*info = -3;
} else if (*n1 < 0) {
*info = -4;
} else if (*lda < *m) {
*info = -6;
} else if (*mv < 0) {
*info = -9;
} else if (*ldv < *m) {
*info = -11;
} else if (*tol <= *eps) {
*info = -14;
} else if (*nsweep < 0) {
*info = -15;
} else if (*lwork < *m) {
*info = -17;
} else {
*info = 0;
}
/* #:( */
if (*info != 0) {
i__1 = -(*info);
xerbla_("SGSVJ1", &i__1);
return 0;
}
if (rsvec) {
mvl = *n;
} else if (applv) {
mvl = *mv;
}
rsvec = rsvec || applv;
rooteps = sqrt(*eps);
rootsfmin = sqrt(*sfmin);
small = *sfmin / *eps;
big = 1.f / *sfmin;
rootbig = 1.f / rootsfmin;
large = big / sqrt((real) (*m * *n));
bigtheta = 1.f / rooteps;
roottol = sqrt(*tol);
/* -#- Initialize the right singular vector matrix -#- */
/* RSVEC = LSAME( JOBV, 'Y' ) */
emptsw = *n1 * (*n - *n1);
notrot = 0;
fastr[0] = 0.f;
/* -#- Row-cyclic pivot strategy with de Rijk's pivoting -#- */
kbl = min(8,*n);
nblr = *n1 / kbl;
if (nblr * kbl != *n1) {
++nblr;
}
/* .. the tiling is nblr-by-nblc [tiles] */
nblc = (*n - *n1) / kbl;
if (nblc * kbl != *n - *n1) {
++nblc;
}
/* Computing 2nd power */
i__1 = kbl;
blskip = i__1 * i__1 + 1;
/* [TP] BLKSKIP is a tuning parameter that depends on SWBAND and KBL. */
rowskip = min(5,kbl);
/* [TP] ROWSKIP is a tuning parameter. */
swband = 0;
/* [TP] SWBAND is a tuning parameter. It is meaningful and effective */
/* if SGESVJ is used as a computational routine in the preconditioned */
/* Jacobi SVD algorithm SGESVJ. */
/* | * * * [x] [x] [x]| */
/* | * * * [x] [x] [x]| Row-cycling in the nblr-by-nblc [x] blocks. */
/* | * * * [x] [x] [x]| Row-cyclic pivoting inside each [x] block. */
/* |[x] [x] [x] * * * | */
/* |[x] [x] [x] * * * | */
/* |[x] [x] [x] * * * | */
i__1 = *nsweep;
for (i__ = 1; i__ <= i__1; ++i__) {
/* .. go go go ... */
mxaapq = 0.f;
mxsinj = 0.f;
iswrot = 0;
notrot = 0;
pskipped = 0;
i__2 = nblr;
for (ibr = 1; ibr <= i__2; ++ibr) {
igl = (ibr - 1) * kbl + 1;
/* ........................................................ */
/* ... go to the off diagonal blocks */
igl = (ibr - 1) * kbl + 1;
i__3 = nblc;
for (jbc = 1; jbc <= i__3; ++jbc) {
jgl = *n1 + (jbc - 1) * kbl + 1;
/* doing the block at ( ibr, jbc ) */
ijblsk = 0;
/* Computing MIN */
i__5 = igl + kbl - 1;
i__4 = min(i__5,*n1);
for (p = igl; p <= i__4; ++p) {
aapp = sva[p];
if (aapp > 0.f) {
pskipped = 0;
/* Computing MIN */
i__6 = jgl + kbl - 1;
i__5 = min(i__6,*n);
for (q = jgl; q <= i__5; ++q) {
aaqq = sva[q];
if (aaqq > 0.f) {
aapp0 = aapp;
/* -#- M x 2 Jacobi SVD -#- */
/* -#- Safe Gram matrix computation -#- */
if (aaqq >= 1.f) {
if (aapp >= aaqq) {
rotok = small * aapp <= aaqq;
} else {
rotok = small * aaqq <= aapp;
}
if (aapp < big / aaqq) {
aapq = sdot_(m, &a[p * a_dim1 + 1], &
c__1, &a[q * a_dim1 + 1], &
c__1) * d__[p] * d__[q] /
aaqq / aapp;
} else {
scopy_(m, &a[p * a_dim1 + 1], &c__1, &
work[1], &c__1);
slascl_("G", &c__0, &c__0, &aapp, &
d__[p], m, &c__1, &work[1],
lda, &ierr);
aapq = sdot_(m, &work[1], &c__1, &a[q
* a_dim1 + 1], &c__1) * d__[q]
/ aaqq;
}
} else {
if (aapp >= aaqq) {
rotok = aapp <= aaqq / small;
} else {
rotok = aaqq <= aapp / small;
}
if (aapp > small / aaqq) {
aapq = sdot_(m, &a[p * a_dim1 + 1], &
c__1, &a[q * a_dim1 + 1], &
c__1) * d__[p] * d__[q] /
aaqq / aapp;
} else {
scopy_(m, &a[q * a_dim1 + 1], &c__1, &
work[1], &c__1);
slascl_("G", &c__0, &c__0, &aaqq, &
d__[q], m, &c__1, &work[1],
lda, &ierr);
aapq = sdot_(m, &work[1], &c__1, &a[p
* a_dim1 + 1], &c__1) * d__[p]
/ aapp;
}
}
/* Computing MAX */
r__1 = mxaapq, r__2 = dabs(aapq);
mxaapq = dmax(r__1,r__2);
/* TO rotate or NOT to rotate, THAT is the question ... */
if (dabs(aapq) > *tol) {
notrot = 0;
/* ROTATED = ROTATED + 1 */
pskipped = 0;
++iswrot;
if (rotok) {
aqoap = aaqq / aapp;
apoaq = aapp / aaqq;
theta = (r__1 = aqoap - apoaq, dabs(
r__1)) * -.5f / aapq;
if (aaqq > aapp0) {
theta = -theta;
}
if (dabs(theta) > bigtheta) {
t = .5f / theta;
fastr[2] = t * d__[p] / d__[q];
fastr[3] = -t * d__[q] / d__[p];
srotm_(m, &a[p * a_dim1 + 1], &
c__1, &a[q * a_dim1 + 1],
&c__1, fastr);
if (rsvec) {
srotm_(&mvl, &v[p * v_dim1 + 1], &c__1, &v[q *
v_dim1 + 1], &c__1, fastr);
}
/* Computing MAX */
r__1 = 0.f, r__2 = t * apoaq *
aapq + 1.f;
sva[q] = aaqq * sqrt((dmax(r__1,
r__2)));
/* Computing MAX */
r__1 = 0.f, r__2 = 1.f - t *
aqoap * aapq;
aapp *= sqrt((dmax(r__1,r__2)));
/* Computing MAX */
r__1 = mxsinj, r__2 = dabs(t);
mxsinj = dmax(r__1,r__2);
} else {
/* .. choose correct signum for THETA and rotate */
thsign = -r_sign(&c_b35, &aapq);
if (aaqq > aapp0) {
thsign = -thsign;
}
t = 1.f / (theta + thsign * sqrt(
theta * theta + 1.f));
cs = sqrt(1.f / (t * t + 1.f));
sn = t * cs;
/* Computing MAX */
r__1 = mxsinj, r__2 = dabs(sn);
mxsinj = dmax(r__1,r__2);
/* Computing MAX */
r__1 = 0.f, r__2 = t * apoaq *
aapq + 1.f;
sva[q] = aaqq * sqrt((dmax(r__1,
r__2)));
aapp *= sqrt(1.f - t * aqoap *
aapq);
apoaq = d__[p] / d__[q];
aqoap = d__[q] / d__[p];
if (d__[p] >= 1.f) {
if (d__[q] >= 1.f) {
fastr[2] = t * apoaq;
fastr[3] = -t * aqoap;
d__[p] *= cs;
d__[q] *= cs;
srotm_(m, &a[p * a_dim1 + 1], &c__1, &a[q *
a_dim1 + 1], &c__1, fastr);
if (rsvec) {
srotm_(&mvl, &v[p * v_dim1 + 1], &c__1, &v[
q * v_dim1 + 1], &c__1, fastr);
}
} else {
r__1 = -t * aqoap;
saxpy_(m, &r__1, &a[q * a_dim1 + 1], &c__1, &a[
p * a_dim1 + 1], &c__1);
r__1 = cs * sn * apoaq;
saxpy_(m, &r__1, &a[p * a_dim1 + 1], &c__1, &a[
q * a_dim1 + 1], &c__1);
if (rsvec) {
r__1 = -t * aqoap;
saxpy_(&mvl, &r__1, &v[q * v_dim1 + 1], &
c__1, &v[p * v_dim1 + 1], &c__1);
r__1 = cs * sn * apoaq;
saxpy_(&mvl, &r__1, &v[p * v_dim1 + 1], &
c__1, &v[q * v_dim1 + 1], &c__1);
}
d__[p] *= cs;
d__[q] /= cs;
}
} else {
if (d__[q] >= 1.f) {
r__1 = t * apoaq;
saxpy_(m, &r__1, &a[p * a_dim1 + 1], &c__1, &a[
q * a_dim1 + 1], &c__1);
r__1 = -cs * sn * aqoap;
saxpy_(m, &r__1, &a[q * a_dim1 + 1], &c__1, &a[
p * a_dim1 + 1], &c__1);
if (rsvec) {
r__1 = t * apoaq;
saxpy_(&mvl, &r__1, &v[p * v_dim1 + 1], &
c__1, &v[q * v_dim1 + 1], &c__1);
r__1 = -cs * sn * aqoap;
saxpy_(&mvl, &r__1, &v[q * v_dim1 + 1], &
c__1, &v[p * v_dim1 + 1], &c__1);
}
d__[p] /= cs;
d__[q] *= cs;
} else {
if (d__[p] >= d__[q]) {
r__1 = -t * aqoap;
saxpy_(m, &r__1, &a[q * a_dim1 + 1], &c__1,
&a[p * a_dim1 + 1], &c__1);
r__1 = cs * sn * apoaq;
saxpy_(m, &r__1, &a[p * a_dim1 + 1], &c__1,
&a[q * a_dim1 + 1], &c__1);
d__[p] *= cs;
d__[q] /= cs;
if (rsvec) {
r__1 = -t * aqoap;
saxpy_(&mvl, &r__1, &v[q * v_dim1 + 1],
&c__1, &v[p * v_dim1 + 1], &
c__1);
r__1 = cs * sn * apoaq;
saxpy_(&mvl, &r__1, &v[p * v_dim1 + 1],
&c__1, &v[q * v_dim1 + 1], &
c__1);
}
} else {
r__1 = t * apoaq;
saxpy_(m, &r__1, &a[p * a_dim1 + 1], &c__1,
&a[q * a_dim1 + 1], &c__1);
r__1 = -cs * sn * aqoap;
saxpy_(m, &r__1, &a[q * a_dim1 + 1], &c__1,
&a[p * a_dim1 + 1], &c__1);
d__[p] /= cs;
d__[q] *= cs;
if (rsvec) {
r__1 = t * apoaq;
saxpy_(&mvl, &r__1, &v[p * v_dim1 + 1],
&c__1, &v[q * v_dim1 + 1], &
c__1);
r__1 = -cs * sn * aqoap;
saxpy_(&mvl, &r__1, &v[q * v_dim1 + 1],
&c__1, &v[p * v_dim1 + 1], &
c__1);
}
}
}
}
}
} else {
if (aapp > aaqq) {
scopy_(m, &a[p * a_dim1 + 1], &
c__1, &work[1], &c__1);
slascl_("G", &c__0, &c__0, &aapp,
&c_b35, m, &c__1, &work[1]
, lda, &ierr);
slascl_("G", &c__0, &c__0, &aaqq,
&c_b35, m, &c__1, &a[q *
a_dim1 + 1], lda, &ierr);
temp1 = -aapq * d__[p] / d__[q];
saxpy_(m, &temp1, &work[1], &c__1,
&a[q * a_dim1 + 1], &
c__1);
slascl_("G", &c__0, &c__0, &c_b35,
&aaqq, m, &c__1, &a[q *
a_dim1 + 1], lda, &ierr);
/* Computing MAX */
r__1 = 0.f, r__2 = 1.f - aapq *
aapq;
sva[q] = aaqq * sqrt((dmax(r__1,
r__2)));
mxsinj = dmax(mxsinj,*sfmin);
} else {
scopy_(m, &a[q * a_dim1 + 1], &
c__1, &work[1], &c__1);
slascl_("G", &c__0, &c__0, &aaqq,
&c_b35, m, &c__1, &work[1]
, lda, &ierr);
slascl_("G", &c__0, &c__0, &aapp,
&c_b35, m, &c__1, &a[p *
a_dim1 + 1], lda, &ierr);
temp1 = -aapq * d__[q] / d__[p];
saxpy_(m, &temp1, &work[1], &c__1,
&a[p * a_dim1 + 1], &
c__1);
slascl_("G", &c__0, &c__0, &c_b35,
&aapp, m, &c__1, &a[p *
a_dim1 + 1], lda, &ierr);
/* Computing MAX */
r__1 = 0.f, r__2 = 1.f - aapq *
aapq;
sva[p] = aapp * sqrt((dmax(r__1,
r__2)));
mxsinj = dmax(mxsinj,*sfmin);
}
}
/* END IF ROTOK THEN ... ELSE */
/* In the case of cancellation in updating SVA(q) */
/* .. recompute SVA(q) */
/* Computing 2nd power */
r__1 = sva[q] / aaqq;
if (r__1 * r__1 <= rooteps) {
if (aaqq < rootbig && aaqq >
rootsfmin) {
sva[q] = snrm2_(m, &a[q * a_dim1
+ 1], &c__1) * d__[q];
} else {
t = 0.f;
aaqq = 0.f;
slassq_(m, &a[q * a_dim1 + 1], &
c__1, &t, &aaqq);
sva[q] = t * sqrt(aaqq) * d__[q];
}
}
/* Computing 2nd power */
r__1 = aapp / aapp0;
if (r__1 * r__1 <= rooteps) {
if (aapp < rootbig && aapp >
rootsfmin) {
aapp = snrm2_(m, &a[p * a_dim1 +
1], &c__1) * d__[p];
} else {
t = 0.f;
aapp = 0.f;
slassq_(m, &a[p * a_dim1 + 1], &
c__1, &t, &aapp);
aapp = t * sqrt(aapp) * d__[p];
}
sva[p] = aapp;
}
/* end of OK rotation */
} else {
++notrot;
/* SKIPPED = SKIPPED + 1 */
++pskipped;
++ijblsk;
}
} else {
++notrot;
++pskipped;
++ijblsk;
}
/* IF ( NOTROT .GE. EMPTSW ) GO TO 2011 */
if (i__ <= swband && ijblsk >= blskip) {
sva[p] = aapp;
notrot = 0;
goto L2011;
}
if (i__ <= swband && pskipped > rowskip) {
aapp = -aapp;
notrot = 0;
goto L2203;
}
/* L2200: */
}
/* end of the q-loop */
L2203:
sva[p] = aapp;
} else {
if (aapp == 0.f) {
/* Computing MIN */
i__5 = jgl + kbl - 1;
notrot = notrot + min(i__5,*n) - jgl + 1;
}
if (aapp < 0.f) {
notrot = 0;
}
/* ** IF ( NOTROT .GE. EMPTSW ) GO TO 2011 */
}
/* L2100: */
}
/* end of the p-loop */
/* L2010: */
}
/* end of the jbc-loop */
L2011:
/* 2011 bailed out of the jbc-loop */
/* Computing MIN */
i__4 = igl + kbl - 1;
i__3 = min(i__4,*n);
for (p = igl; p <= i__3; ++p) {
sva[p] = (r__1 = sva[p], dabs(r__1));
/* L2012: */
}
/* ** IF ( NOTROT .GE. EMPTSW ) GO TO 1994 */
/* L2000: */
}
/* 2000 :: end of the ibr-loop */
/* .. update SVA(N) */
if (sva[*n] < rootbig && sva[*n] > rootsfmin) {
sva[*n] = snrm2_(m, &a[*n * a_dim1 + 1], &c__1) * d__[*n];
} else {
t = 0.f;
aapp = 0.f;
slassq_(m, &a[*n * a_dim1 + 1], &c__1, &t, &aapp);
sva[*n] = t * sqrt(aapp) * d__[*n];
}
/* Additional steering devices */
if (i__ < swband && (mxaapq <= roottol || iswrot <= *n)) {
swband = i__;
}
if (i__ > swband + 1 && mxaapq < (real) (*n) * *tol && (real) (*n) *
mxaapq * mxsinj < *tol) {
goto L1994;
}
if (notrot >= emptsw) {
goto L1994;
}
/* L1993: */
}
/* end i=1:NSWEEP loop */
/* #:) Reaching this point means that the procedure has completed the given */
/* number of sweeps. */
*info = *nsweep - 1;
goto L1995;
L1994:
/* #:) Reaching this point means that during the i-th sweep all pivots were */
/* below the given threshold, causing early exit. */
*info = 0;
/* #:) INFO = 0 confirms successful iterations. */
L1995:
/* Sort the vector D */
i__1 = *n - 1;
for (p = 1; p <= i__1; ++p) {
i__2 = *n - p + 1;
q = isamax_(&i__2, &sva[p], &c__1) + p - 1;
if (p != q) {
temp1 = sva[p];
sva[p] = sva[q];
sva[q] = temp1;
temp1 = d__[p];
d__[p] = d__[q];
d__[q] = temp1;
sswap_(m, &a[p * a_dim1 + 1], &c__1, &a[q * a_dim1 + 1], &c__1);
if (rsvec) {
sswap_(&mvl, &v[p * v_dim1 + 1], &c__1, &v[q * v_dim1 + 1], &
c__1);
}
}
/* L5991: */
}
return 0;
/* .. */
/* .. END OF SGSVJ1 */
/* .. */
} /* sgsvj1_ */