/* Subroutine */ int cheevr_(char *jobz, char *range, char *uplo, integer *n,
complex *a, integer *lda, real *vl, real *vu, integer *il, integer *
iu, real *abstol, integer *m, real *w, complex *z__, integer *ldz,
integer *isuppz, complex *work, integer *lwork, real *rwork, integer *
lrwork, integer *iwork, integer *liwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, z_dim1, z_offset, i__1, i__2;
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
integer i__, j, nb, jj;
real eps, vll, vuu, tmp1, anrm;
integer imax;
real rmin, rmax;
logical test;
integer itmp1, indrd, indre;
real sigma;
extern logical lsame_(char *, char *);
integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
char order[1];
integer indwk;
extern /* Subroutine */ int cswap_(integer *, complex *, integer *,
complex *, integer *);
integer lwmin;
logical lower;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *);
logical wantz, alleig, indeig;
integer iscale, ieeeok, indibl, indrdd, indifl, indree;
logical valeig;
extern doublereal slamch_(char *);
extern /* Subroutine */ int chetrd_(char *, integer *, complex *, integer
*, real *, real *, complex *, complex *, integer *, integer *), csscal_(integer *, real *, complex *, integer *);
real safmin;
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
extern /* Subroutine */ int xerbla_(char *, integer *);
real abstll, bignum;
integer indtau, indisp;
extern /* Subroutine */ int cstein_(integer *, real *, real *, integer *,
real *, integer *, integer *, complex *, integer *, real *,
integer *, integer *, integer *);
integer indiwo, indwkn;
extern doublereal clansy_(char *, char *, integer *, complex *, integer *,
real *);
extern /* Subroutine */ int cstemr_(char *, char *, integer *, real *,
real *, real *, real *, integer *, integer *, integer *, real *,
complex *, integer *, integer *, integer *, logical *, real *,
integer *, integer *, integer *, integer *);
integer indrwk, liwmin;
logical tryrac;
extern /* Subroutine */ int ssterf_(integer *, real *, real *, integer *);
integer lrwmin, llwrkn, llwork, nsplit;
real smlnum;
extern /* Subroutine */ int cunmtr_(char *, char *, char *, integer *,
integer *, complex *, integer *, complex *, complex *, integer *,
complex *, integer *, integer *), sstebz_(
char *, char *, integer *, real *, real *, integer *, integer *,
real *, real *, real *, integer *, integer *, real *, integer *,
integer *, real *, integer *, integer *);
logical lquery;
integer lwkopt, llrwork;
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CHEEVR computes selected eigenvalues and, optionally, eigenvectors */
/* of a complex Hermitian matrix A. Eigenvalues and eigenvectors can */
/* be selected by specifying either a range of values or a range of */
/* indices for the desired eigenvalues. */
/* CHEEVR first reduces the matrix A to tridiagonal form T with a call */
/* to CHETRD. Then, whenever possible, CHEEVR calls CSTEMR to compute */
/* the eigenspectrum using Relatively Robust Representations. CSTEMR */
/* computes eigenvalues by the dqds algorithm, while orthogonal */
/* eigenvectors are computed from various "good" L D L^T representations */
/* (also known as Relatively Robust Representations). Gram-Schmidt */
/* orthogonalization is avoided as far as possible. More specifically, */
/* the various steps of the algorithm are as follows. */
/* For each unreduced block (submatrix) of T, */
/* (a) Compute T - sigma I = L D L^T, so that L and D */
/* define all the wanted eigenvalues to high relative accuracy. */
/* This means that small relative changes in the entries of D and L */
/* cause only small relative changes in the eigenvalues and */
/* eigenvectors. The standard (unfactored) representation of the */
/* tridiagonal matrix T does not have this property in general. */
/* (b) Compute the eigenvalues to suitable accuracy. */
/* If the eigenvectors are desired, the algorithm attains full */
/* accuracy of the computed eigenvalues only right before */
/* the corresponding vectors have to be computed, see steps c) and d). */
/* (c) For each cluster of close eigenvalues, select a new */
/* shift close to the cluster, find a new factorization, and refine */
/* the shifted eigenvalues to suitable accuracy. */
/* (d) For each eigenvalue with a large enough relative separation compute */
/* the corresponding eigenvector by forming a rank revealing twisted */
/* factorization. Go back to (c) for any clusters that remain. */
/* The desired accuracy of the output can be specified by the input */
/* parameter ABSTOL. */
/* For more details, see DSTEMR's documentation and: */
/* - Inderjit S. Dhillon and Beresford N. Parlett: "Multiple representations */
/* to compute orthogonal eigenvectors of symmetric tridiagonal matrices," */
/* Linear Algebra and its Applications, 387(1), pp. 1-28, August 2004. */
/* - Inderjit Dhillon and Beresford Parlett: "Orthogonal Eigenvectors and */
/* Relative Gaps," SIAM Journal on Matrix Analysis and Applications, Vol. 25, */
/* 2004. Also LAPACK Working Note 154. */
/* - Inderjit Dhillon: "A new O(n^2) algorithm for the symmetric */
/* tridiagonal eigenvalue/eigenvector problem", */
/* Computer Science Division Technical Report No. UCB/CSD-97-971, */
/* UC Berkeley, May 1997. */
/* Note 1 : CHEEVR calls CSTEMR when the full spectrum is requested */
/* on machines which conform to the ieee-754 floating point standard. */
/* CHEEVR calls SSTEBZ and CSTEIN on non-ieee machines and */
/* when partial spectrum requests are made. */
/* Normal execution of CSTEMR may create NaNs and infinities and */
/* hence may abort due to a floating point exception in environments */
/* which do not handle NaNs and infinities in the ieee standard default */
/* manner. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* RANGE (input) CHARACTER*1 */
/* = 'A': all eigenvalues will be found. */
/* = 'V': all eigenvalues in the half-open interval (VL,VU] */
/* will be found. */
/* = 'I': the IL-th through IU-th eigenvalues will be found. */
/* ********* For RANGE = 'V' or 'I' and IU - IL < N - 1, SSTEBZ and */
/* ********* CSTEIN are called */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA, N) */
/* On entry, the Hermitian matrix A. If UPLO = 'U', the */
/* leading N-by-N upper triangular part of A contains the */
/* upper triangular part of the matrix A. If UPLO = 'L', */
/* the leading N-by-N lower triangular part of A contains */
/* the lower triangular part of the matrix A. */
/* On exit, the lower triangle (if UPLO='L') or the upper */
/* triangle (if UPLO='U') of A, including the diagonal, is */
/* destroyed. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* VL (input) REAL */
/* VU (input) REAL */
/* If RANGE='V', the lower and upper bounds of the interval to */
/* be searched for eigenvalues. VL < VU. */
/* Not referenced if RANGE = 'A' or 'I'. */
/* IL (input) INTEGER */
/* IU (input) INTEGER */
/* If RANGE='I', the indices (in ascending order) of the */
/* smallest and largest eigenvalues to be returned. */
/* 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. */
/* Not referenced if RANGE = 'A' or 'V'. */
/* ABSTOL (input) REAL */
/* The absolute error tolerance for the eigenvalues. */
/* An approximate eigenvalue is accepted as converged */
/* when it is determined to lie in an interval [a,b] */
/* of width less than or equal to */
/* ABSTOL + EPS * max( |a|,|b| ) , */
/* where EPS is the machine precision. If ABSTOL is less than */
/* or equal to zero, then EPS*|T| will be used in its place, */
/* where |T| is the 1-norm of the tridiagonal matrix obtained */
/* by reducing A to tridiagonal form. */
/* See "Computing Small Singular Values of Bidiagonal Matrices */
/* with Guaranteed High Relative Accuracy," by Demmel and */
/* Kahan, LAPACK Working Note #3. */
/* If high relative accuracy is important, set ABSTOL to */
/* SLAMCH( 'Safe minimum' ). Doing so will guarantee that */
/* eigenvalues are computed to high relative accuracy when */
/* possible in future releases. The current code does not */
/* make any guarantees about high relative accuracy, but */
/* furutre releases will. See J. Barlow and J. Demmel, */
/* "Computing Accurate Eigensystems of Scaled Diagonally */
/* Dominant Matrices", LAPACK Working Note #7, for a discussion */
/* of which matrices define their eigenvalues to high relative */
/* accuracy. */
/* M (output) INTEGER */
/* The total number of eigenvalues found. 0 <= M <= N. */
/* If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. */
/* W (output) REAL array, dimension (N) */
/* The first M elements contain the selected eigenvalues in */
/* ascending order. */
/* Z (output) COMPLEX array, dimension (LDZ, max(1,M)) */
/* If JOBZ = 'V', then if INFO = 0, the first M columns of Z */
/* contain the orthonormal eigenvectors of the matrix A */
/* corresponding to the selected eigenvalues, with the i-th */
/* column of Z holding the eigenvector associated with W(i). */
/* If JOBZ = 'N', then Z is not referenced. */
/* Note: the user must ensure that at least max(1,M) columns are */
/* supplied in the array Z; if RANGE = 'V', the exact value of M */
/* is not known in advance and an upper bound must be used. */
/* LDZ (input) INTEGER */
/* The leading dimension of the array Z. LDZ >= 1, and if */
/* JOBZ = 'V', LDZ >= max(1,N). */
/* ISUPPZ (output) INTEGER array, dimension ( 2*max(1,M) ) */
/* The support of the eigenvectors in Z, i.e., the indices */
/* indicating the nonzero elements in Z. The i-th eigenvector */
/* is nonzero only in elements ISUPPZ( 2*i-1 ) through */
/* ISUPPZ( 2*i ). */
/* ********* Implemented only for RANGE = 'A' or 'I' and IU - IL = N - 1 */
/* WORK (workspace/output) COMPLEX array, dimension (MAX(1,LWORK)) */
/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
/* LWORK (input) INTEGER */
/* The length of the array WORK. LWORK >= max(1,2*N). */
/* For optimal efficiency, LWORK >= (NB+1)*N, */
/* where NB is the max of the blocksize for CHETRD and for */
/* CUNMTR as returned by ILAENV. */
/* If LWORK = -1, then a workspace query is assumed; the routine */
/* only calculates the optimal sizes of the WORK, RWORK and */
/* IWORK arrays, returns these values as the first entries of */
/* the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* RWORK (workspace/output) REAL array, dimension (MAX(1,LRWORK)) */
/* On exit, if INFO = 0, RWORK(1) returns the optimal */
/* (and minimal) LRWORK. */
/* LRWORK (input) INTEGER */
/* The length of the array RWORK. LRWORK >= max(1,24*N). */
/* If LRWORK = -1, then a workspace query is assumed; the */
/* routine only calculates the optimal sizes of the WORK, RWORK */
/* and IWORK arrays, returns these values as the first entries */
/* of the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* IWORK (workspace/output) INTEGER array, dimension (MAX(1,LIWORK)) */
/* On exit, if INFO = 0, IWORK(1) returns the optimal */
/* (and minimal) LIWORK. */
/* LIWORK (input) INTEGER */
/* The dimension of the array IWORK. LIWORK >= max(1,10*N). */
/* If LIWORK = -1, then a workspace query is assumed; the */
/* routine only calculates the optimal sizes of the WORK, RWORK */
/* and IWORK arrays, returns these values as the first entries */
/* of the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: Internal error */
/* Further Details */
/* =============== */
/* Based on contributions by */
/* Inderjit Dhillon, IBM Almaden, USA */
/* Osni Marques, LBNL/NERSC, USA */
/* Ken Stanley, Computer Science Division, University of */
/* California at Berkeley, USA */
/* Jason Riedy, Computer Science Division, University of */
/* California at Berkeley, USA */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--isuppz;
--work;
--rwork;
--iwork;
/* Function Body */
ieeeok = ilaenv_(&c__10, "CHEEVR", "N", &c__1, &c__2, &c__3, &c__4);
lower = lsame_(uplo, "L");
wantz = lsame_(jobz, "V");
alleig = lsame_(range, "A");
valeig = lsame_(range, "V");
indeig = lsame_(range, "I");
lquery = *lwork == -1 || *lrwork == -1 || *liwork == -1;
/* Computing MAX */
i__1 = 1, i__2 = *n * 24;
lrwmin = max(i__1,i__2);
/* Computing MAX */
i__1 = 1, i__2 = *n * 10;
liwmin = max(i__1,i__2);
/* Computing MAX */
i__1 = 1, i__2 = *n << 1;
lwmin = max(i__1,i__2);
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -3;
} else if (*n < 0) {
*info = -4;
} else if (*lda < max(1,*n)) {
*info = -6;
} else {
if (valeig) {
if (*n > 0 && *vu <= *vl) {
*info = -8;
}
} else if (indeig) {
if (*il < 1 || *il > max(1,*n)) {
*info = -9;
} else if (*iu < min(*n,*il) || *iu > *n) {
*info = -10;
}
}
}
if (*info == 0) {
if (*ldz < 1 || wantz && *ldz < *n) {
*info = -15;
}
}
if (*info == 0) {
nb = ilaenv_(&c__1, "CHETRD", uplo, n, &c_n1, &c_n1, &c_n1);
/* Computing MAX */
i__1 = nb, i__2 = ilaenv_(&c__1, "CUNMTR", uplo, n, &c_n1, &c_n1, &
c_n1);
nb = max(i__1,i__2);
/* Computing MAX */
i__1 = (nb + 1) * *n;
lwkopt = max(i__1,lwmin);
work[1].r = (real) lwkopt, work[1].i = 0.f;
rwork[1] = (real) lrwmin;
iwork[1] = liwmin;
if (*lwork < lwmin && ! lquery) {
*info = -18;
} else if (*lrwork < lrwmin && ! lquery) {
*info = -20;
} else if (*liwork < liwmin && ! lquery) {
*info = -22;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CHEEVR", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
*m = 0;
if (*n == 0) {
work[1].r = 1.f, work[1].i = 0.f;
return 0;
}
if (*n == 1) {
work[1].r = 2.f, work[1].i = 0.f;
if (alleig || indeig) {
*m = 1;
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
} else {
i__1 = a_dim1 + 1;
i__2 = a_dim1 + 1;
if (*vl < a[i__1].r && *vu >= a[i__2].r) {
*m = 1;
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
}
}
if (wantz) {
i__1 = z_dim1 + 1;
z__[i__1].r = 1.f, z__[i__1].i = 0.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
/* Computing MIN */
r__1 = sqrt(bignum), r__2 = 1.f / sqrt(sqrt(safmin));
rmax = dmin(r__1,r__2);
/* Scale matrix to allowable range, if necessary. */
iscale = 0;
abstll = *abstol;
if (valeig) {
vll = *vl;
vuu = *vu;
}
anrm = clansy_("M", uplo, n, &a[a_offset], lda, &rwork[1]);
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
if (lower) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *n - j + 1;
csscal_(&i__2, &sigma, &a[j + j * a_dim1], &c__1);
/* L10: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
csscal_(&j, &sigma, &a[j * a_dim1 + 1], &c__1);
/* L20: */
}
}
if (*abstol > 0.f) {
abstll = *abstol * sigma;
}
if (valeig) {
vll = *vl * sigma;
vuu = *vu * sigma;
}
}
/* Initialize indices into workspaces. Note: The IWORK indices are */
/* used only if SSTERF or CSTEMR fail. */
/* WORK(INDTAU:INDTAU+N-1) stores the complex scalar factors of the */
/* elementary reflectors used in CHETRD. */
indtau = 1;
/* INDWK is the starting offset of the remaining complex workspace, */
/* and LLWORK is the remaining complex workspace size. */
indwk = indtau + *n;
llwork = *lwork - indwk + 1;
/* RWORK(INDRD:INDRD+N-1) stores the real tridiagonal's diagonal */
/* entries. */
indrd = 1;
/* RWORK(INDRE:INDRE+N-1) stores the off-diagonal entries of the */
/* tridiagonal matrix from CHETRD. */
indre = indrd + *n;
/* RWORK(INDRDD:INDRDD+N-1) is a copy of the diagonal entries over */
/* -written by CSTEMR (the SSTERF path copies the diagonal to W). */
indrdd = indre + *n;
/* RWORK(INDREE:INDREE+N-1) is a copy of the off-diagonal entries over */
/* -written while computing the eigenvalues in SSTERF and CSTEMR. */
indree = indrdd + *n;
/* INDRWK is the starting offset of the left-over real workspace, and */
/* LLRWORK is the remaining workspace size. */
indrwk = indree + *n;
llrwork = *lrwork - indrwk + 1;
/* IWORK(INDIBL:INDIBL+M-1) corresponds to IBLOCK in SSTEBZ and */
/* stores the block indices of each of the M<=N eigenvalues. */
indibl = 1;
/* IWORK(INDISP:INDISP+NSPLIT-1) corresponds to ISPLIT in SSTEBZ and */
/* stores the starting and finishing indices of each block. */
indisp = indibl + *n;
/* IWORK(INDIFL:INDIFL+N-1) stores the indices of eigenvectors */
/* that corresponding to eigenvectors that fail to converge in */
/* SSTEIN. This information is discarded; if any fail, the driver */
/* returns INFO > 0. */
indifl = indisp + *n;
/* INDIWO is the offset of the remaining integer workspace. */
indiwo = indisp + *n;
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
chetrd_(uplo, n, &a[a_offset], lda, &rwork[indrd], &rwork[indre], &work[
indtau], &work[indwk], &llwork, &iinfo);
/* If all eigenvalues are desired */
/* then call SSTERF or CSTEMR and CUNMTR. */
test = FALSE_;
if (indeig) {
if (*il == 1 && *iu == *n) {
test = TRUE_;
}
}
if ((alleig || test) && ieeeok == 1) {
if (! wantz) {
scopy_(n, &rwork[indrd], &c__1, &w[1], &c__1);
i__1 = *n - 1;
scopy_(&i__1, &rwork[indre], &c__1, &rwork[indree], &c__1);
ssterf_(n, &w[1], &rwork[indree], info);
} else {
i__1 = *n - 1;
scopy_(&i__1, &rwork[indre], &c__1, &rwork[indree], &c__1);
scopy_(n, &rwork[indrd], &c__1, &rwork[indrdd], &c__1);
if (*abstol <= *n * 2.f * eps) {
tryrac = TRUE_;
} else {
tryrac = FALSE_;
}
cstemr_(jobz, "A", n, &rwork[indrdd], &rwork[indree], vl, vu, il,
iu, m, &w[1], &z__[z_offset], ldz, n, &isuppz[1], &tryrac,
&rwork[indrwk], &llrwork, &iwork[1], liwork, info);
/* Apply unitary matrix used in reduction to tridiagonal */
/* form to eigenvectors returned by CSTEIN. */
if (wantz && *info == 0) {
indwkn = indwk;
llwrkn = *lwork - indwkn + 1;
cunmtr_("L", uplo, "N", n, m, &a[a_offset], lda, &work[indtau]
, &z__[z_offset], ldz, &work[indwkn], &llwrkn, &iinfo);
}
}
if (*info == 0) {
*m = *n;
goto L30;
}
*info = 0;
}
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, CSTEIN. */
/* Also call SSTEBZ and CSTEIN if CSTEMR fails. */
if (wantz) {
*(unsigned char *)order = 'B';
} else {
*(unsigned char *)order = 'E';
}
sstebz_(range, order, n, &vll, &vuu, il, iu, &abstll, &rwork[indrd], &
rwork[indre], m, &nsplit, &w[1], &iwork[indibl], &iwork[indisp], &
rwork[indrwk], &iwork[indiwo], info);
if (wantz) {
cstein_(n, &rwork[indrd], &rwork[indre], m, &w[1], &iwork[indibl], &
iwork[indisp], &z__[z_offset], ldz, &rwork[indrwk], &iwork[
indiwo], &iwork[indifl], info);
/* Apply unitary matrix used in reduction to tridiagonal */
/* form to eigenvectors returned by CSTEIN. */
indwkn = indwk;
llwrkn = *lwork - indwkn + 1;
cunmtr_("L", uplo, "N", n, m, &a[a_offset], lda, &work[indtau], &z__[
z_offset], ldz, &work[indwkn], &llwrkn, &iinfo);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
L30:
if (iscale == 1) {
if (*info == 0) {
imax = *m;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
/* If eigenvalues are not in order, then sort them, along with */
/* eigenvectors. */
if (wantz) {
i__1 = *m - 1;
for (j = 1; j <= i__1; ++j) {
i__ = 0;
tmp1 = w[j];
i__2 = *m;
for (jj = j + 1; jj <= i__2; ++jj) {
if (w[jj] < tmp1) {
i__ = jj;
tmp1 = w[jj];
}
/* L40: */
}
if (i__ != 0) {
itmp1 = iwork[indibl + i__ - 1];
w[i__] = w[j];
iwork[indibl + i__ - 1] = iwork[indibl + j - 1];
w[j] = tmp1;
iwork[indibl + j - 1] = itmp1;
cswap_(n, &z__[i__ * z_dim1 + 1], &c__1, &z__[j * z_dim1 + 1],
&c__1);
}
/* L50: */
}
}
/* Set WORK(1) to optimal workspace size. */
work[1].r = (real) lwkopt, work[1].i = 0.f;
rwork[1] = (real) lrwmin;
iwork[1] = liwmin;
return 0;
/* End of CHEEVR */
} /* cheevr_ */
/* Subroutine */
int cheev_(char *jobz, char *uplo, integer *n, complex *a, integer *lda, real *w, complex *work, integer *lwork, real *rwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
real r__1;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
integer nb;
real eps;
integer inde;
real anrm;
integer imax;
real rmin, rmax, sigma;
extern logical lsame_(char *, char *);
integer iinfo;
extern /* Subroutine */
int sscal_(integer *, real *, real *, integer *);
logical lower, wantz;
extern real clanhe_(char *, char *, integer *, complex *, integer *, real *);
integer iscale;
extern /* Subroutine */
int clascl_(char *, integer *, integer *, real *, real *, integer *, integer *, complex *, integer *, integer *);
extern real slamch_(char *);
extern /* Subroutine */
int chetrd_(char *, integer *, complex *, integer *, real *, real *, complex *, complex *, integer *, integer *);
real safmin;
extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *);
extern /* Subroutine */
int xerbla_(char *, integer *);
real bignum;
integer indtau, indwrk;
extern /* Subroutine */
int csteqr_(char *, integer *, real *, real *, complex *, integer *, real *, integer *), cungtr_(char *, integer *, complex *, integer *, complex *, complex *, integer *, integer *), ssterf_(integer *, real *, real *, integer *);
integer llwork;
real smlnum;
integer lwkopt;
logical lquery;
/* -- LAPACK driver routine (version 3.4.0) -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* November 2011 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
--work;
--rwork;
/* Function Body */
wantz = lsame_(jobz, "V");
lower = lsame_(uplo, "L");
lquery = *lwork == -1;
*info = 0;
if (! (wantz || lsame_(jobz, "N")))
{
*info = -1;
}
else if (! (lower || lsame_(uplo, "U")))
{
*info = -2;
}
else if (*n < 0)
{
*info = -3;
}
else if (*lda < max(1,*n))
{
*info = -5;
}
if (*info == 0)
{
nb = ilaenv_(&c__1, "CHETRD", uplo, n, &c_n1, &c_n1, &c_n1);
/* Computing MAX */
i__1 = 1;
i__2 = (nb + 1) * *n; // , expr subst
lwkopt = max(i__1,i__2);
work[1].r = (real) lwkopt;
work[1].i = 0.f; // , expr subst
/* Computing MAX */
i__1 = 1;
i__2 = (*n << 1) - 1; // , expr subst
if (*lwork < max(i__1,i__2) && ! lquery)
{
*info = -8;
}
}
if (*info != 0)
{
i__1 = -(*info);
xerbla_("CHEEV ", &i__1);
return 0;
}
else if (lquery)
{
return 0;
}
/* Quick return if possible */
if (*n == 0)
{
return 0;
}
if (*n == 1)
{
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
work[1].r = 1.f;
work[1].i = 0.f; // , expr subst
if (wantz)
{
i__1 = a_dim1 + 1;
a[i__1].r = 1.f;
a[i__1].i = 0.f; // , expr subst
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
rmax = sqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = clanhe_("M", uplo, n, &a[a_offset], lda, &rwork[1]);
iscale = 0;
if (anrm > 0.f && anrm < rmin)
{
iscale = 1;
sigma = rmin / anrm;
}
else if (anrm > rmax)
{
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1)
{
clascl_(uplo, &c__0, &c__0, &c_b18, &sigma, n, n, &a[a_offset], lda, info);
}
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
inde = 1;
indtau = 1;
indwrk = indtau + *n;
llwork = *lwork - indwrk + 1;
chetrd_(uplo, n, &a[a_offset], lda, &w[1], &rwork[inde], &work[indtau], & work[indwrk], &llwork, &iinfo);
/* For eigenvalues only, call SSTERF. For eigenvectors, first call */
/* CUNGTR to generate the unitary matrix, then call CSTEQR. */
if (! wantz)
{
ssterf_(n, &w[1], &rwork[inde], info);
}
else
{
cungtr_(uplo, n, &a[a_offset], lda, &work[indtau], &work[indwrk], & llwork, &iinfo);
indwrk = inde + *n;
csteqr_(jobz, n, &w[1], &rwork[inde], &a[a_offset], lda, &rwork[ indwrk], info);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1)
{
if (*info == 0)
{
imax = *n;
}
else
{
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
/* Set WORK(1) to optimal complex workspace size. */
work[1].r = (real) lwkopt;
work[1].i = 0.f; // , expr subst
return 0;
/* End of CHEEV */
}
/* Subroutine */ int cheev_(char *jobz, char *uplo, integer *n, complex *a,
integer *lda, real *w, complex *work, integer *lwork, real *rwork,
integer *info, ftnlen jobz_len, ftnlen uplo_len)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
real r__1;
complex q__1;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
static integer nb;
static real eps;
static integer inde;
static real anrm;
static integer imax;
static real rmin, rmax;
static integer lopt;
static real sigma;
extern logical lsame_(char *, char *, ftnlen, ftnlen);
static integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
static logical lower, wantz;
extern doublereal clanhe_(char *, char *, integer *, complex *, integer *,
real *, ftnlen, ftnlen);
static integer iscale;
extern /* Subroutine */ int clascl_(char *, integer *, integer *, real *,
real *, integer *, integer *, complex *, integer *, integer *,
ftnlen);
extern doublereal slamch_(char *, ftnlen);
extern /* Subroutine */ int chetrd_(char *, integer *, complex *, integer
*, real *, real *, complex *, complex *, integer *, integer *,
ftnlen);
static real safmin;
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *, ftnlen, ftnlen);
extern /* Subroutine */ int xerbla_(char *, integer *, ftnlen);
static real bignum;
static integer indtau, indwrk;
extern /* Subroutine */ int csteqr_(char *, integer *, real *, real *,
complex *, integer *, real *, integer *, ftnlen), cungtr_(char *,
integer *, complex *, integer *, complex *, complex *, integer *,
integer *, ftnlen), ssterf_(integer *, real *, real *, integer *);
static integer llwork;
static real smlnum;
static integer lwkopt;
static logical lquery;
/* -- LAPACK driver routine (version 3.0) -- */
/* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/* Courant Institute, Argonne National Lab, and Rice University */
/* June 30, 1999 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CHEEV computes all eigenvalues and, optionally, eigenvectors of a */
/* complex Hermitian matrix A. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA, N) */
/* On entry, the Hermitian matrix A. If UPLO = 'U', the */
/* leading N-by-N upper triangular part of A contains the */
/* upper triangular part of the matrix A. If UPLO = 'L', */
/* the leading N-by-N lower triangular part of A contains */
/* the lower triangular part of the matrix A. */
/* On exit, if JOBZ = 'V', then if INFO = 0, A contains the */
/* orthonormal eigenvectors of the matrix A. */
/* If JOBZ = 'N', then on exit the lower triangle (if UPLO='L') */
/* or the upper triangle (if UPLO='U') of A, including the */
/* diagonal, is destroyed. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* W (output) REAL array, dimension (N) */
/* If INFO = 0, the eigenvalues in ascending order. */
/* WORK (workspace/output) COMPLEX array, dimension (LWORK) */
/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
/* LWORK (input) INTEGER */
/* The length of the array WORK. LWORK >= max(1,2*N-1). */
/* For optimal efficiency, LWORK >= (NB+1)*N, */
/* where NB is the blocksize for CHETRD returned by ILAENV. */
/* 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 (max(1, 3*N-2)) */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: if INFO = i, the algorithm failed to converge; i */
/* off-diagonal elements of an intermediate tridiagonal */
/* form did not converge to zero. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
--work;
--rwork;
/* Function Body */
wantz = lsame_(jobz, "V", (ftnlen)1, (ftnlen)1);
lower = lsame_(uplo, "L", (ftnlen)1, (ftnlen)1);
lquery = *lwork == -1;
*info = 0;
if (! (wantz || lsame_(jobz, "N", (ftnlen)1, (ftnlen)1))) {
*info = -1;
} else if (! (lower || lsame_(uplo, "U", (ftnlen)1, (ftnlen)1))) {
*info = -2;
} else if (*n < 0) {
*info = -3;
} else if (*lda < max(1,*n)) {
*info = -5;
} else /* if(complicated condition) */ {
/* Computing MAX */
i__1 = 1, i__2 = (*n << 1) - 1;
if (*lwork < max(i__1,i__2) && ! lquery) {
*info = -8;
}
}
if (*info == 0) {
nb = ilaenv_(&c__1, "CHETRD", uplo, n, &c_n1, &c_n1, &c_n1, (ftnlen)6,
(ftnlen)1);
/* Computing MAX */
i__1 = 1, i__2 = (nb + 1) * *n;
lwkopt = max(i__1,i__2);
work[1].r = (real) lwkopt, work[1].i = 0.f;
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CHEEV ", &i__1, (ftnlen)6);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
if (*n == 0) {
work[1].r = 1.f, work[1].i = 0.f;
return 0;
}
if (*n == 1) {
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
work[1].r = 3.f, work[1].i = 0.f;
if (wantz) {
i__1 = a_dim1 + 1;
a[i__1].r = 1.f, a[i__1].i = 0.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum", (ftnlen)12);
eps = slamch_("Precision", (ftnlen)9);
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
rmax = sqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = clanhe_("M", uplo, n, &a[a_offset], lda, &rwork[1], (ftnlen)1, (
ftnlen)1);
iscale = 0;
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
clascl_(uplo, &c__0, &c__0, &c_b18, &sigma, n, n, &a[a_offset], lda,
info, (ftnlen)1);
}
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
inde = 1;
indtau = 1;
indwrk = indtau + *n;
llwork = *lwork - indwrk + 1;
chetrd_(uplo, n, &a[a_offset], lda, &w[1], &rwork[inde], &work[indtau], &
work[indwrk], &llwork, &iinfo, (ftnlen)1);
i__1 = indwrk;
q__1.r = *n + work[i__1].r, q__1.i = work[i__1].i;
lopt = q__1.r;
/* For eigenvalues only, call SSTERF. For eigenvectors, first call */
/* CUNGTR to generate the unitary matrix, then call CSTEQR. */
if (! wantz) {
ssterf_(n, &w[1], &rwork[inde], info);
} else {
cungtr_(uplo, n, &a[a_offset], lda, &work[indtau], &work[indwrk], &
llwork, &iinfo, (ftnlen)1);
indwrk = inde + *n;
csteqr_(jobz, n, &w[1], &rwork[inde], &a[a_offset], lda, &rwork[
indwrk], info, (ftnlen)1);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1) {
if (*info == 0) {
imax = *n;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
/* Set WORK(1) to optimal complex workspace size. */
work[1].r = (real) lwkopt, work[1].i = 0.f;
return 0;
/* End of CHEEV */
} /* cheev_ */
/* Subroutine */ int cheevd_(char *jobz, char *uplo, integer *n, complex *a,
integer *lda, real *w, complex *work, integer *lwork, real *rwork,
integer *lrwork, integer *iwork, integer *liwork, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2;
real r__1;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
real eps;
integer inde;
real anrm;
integer imax;
real rmin, rmax;
integer lopt;
real sigma;
extern logical lsame_(char *, char *);
integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
integer lwmin, liopt;
logical lower;
integer llrwk, lropt;
logical wantz;
integer indwk2, llwrk2;
extern doublereal clanhe_(char *, char *, integer *, complex *, integer *,
real *);
integer iscale;
extern /* Subroutine */ int clascl_(char *, integer *, integer *, real *,
real *, integer *, integer *, complex *, integer *, integer *), cstedc_(char *, integer *, real *, real *, complex *,
integer *, complex *, integer *, real *, integer *, integer *,
integer *, integer *);
extern doublereal slamch_(char *);
extern /* Subroutine */ int chetrd_(char *, integer *, complex *, integer
*, real *, real *, complex *, complex *, integer *, integer *), clacpy_(char *, integer *, integer *, complex *, integer
*, complex *, integer *);
real safmin;
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
extern /* Subroutine */ int xerbla_(char *, integer *);
real bignum;
integer indtau, indrwk, indwrk, liwmin;
extern /* Subroutine */ int ssterf_(integer *, real *, real *, integer *);
integer lrwmin;
extern /* Subroutine */ int cunmtr_(char *, char *, char *, integer *,
integer *, complex *, integer *, complex *, complex *, integer *,
complex *, integer *, integer *);
integer llwork;
real smlnum;
logical lquery;
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CHEEVD computes all eigenvalues and, optionally, eigenvectors of a */
/* complex Hermitian matrix A. If eigenvectors are desired, it uses a */
/* divide and conquer algorithm. */
/* The divide and conquer algorithm makes very mild assumptions about */
/* floating point arithmetic. It will work on machines with a guard */
/* digit in add/subtract, or on those binary machines without guard */
/* digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or */
/* Cray-2. It could conceivably fail on hexadecimal or decimal machines */
/* without guard digits, but we know of none. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA, N) */
/* On entry, the Hermitian matrix A. If UPLO = 'U', the */
/* leading N-by-N upper triangular part of A contains the */
/* upper triangular part of the matrix A. If UPLO = 'L', */
/* the leading N-by-N lower triangular part of A contains */
/* the lower triangular part of the matrix A. */
/* On exit, if JOBZ = 'V', then if INFO = 0, A contains the */
/* orthonormal eigenvectors of the matrix A. */
/* If JOBZ = 'N', then on exit the lower triangle (if UPLO='L') */
/* or the upper triangle (if UPLO='U') of A, including the */
/* diagonal, is destroyed. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* W (output) REAL array, dimension (N) */
/* If INFO = 0, the eigenvalues in ascending order. */
/* WORK (workspace/output) COMPLEX array, dimension (MAX(1,LWORK)) */
/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
/* LWORK (input) INTEGER */
/* The length of the array WORK. */
/* If N <= 1, LWORK must be at least 1. */
/* If JOBZ = 'N' and N > 1, LWORK must be at least N + 1. */
/* If JOBZ = 'V' and N > 1, LWORK must be at least 2*N + N**2. */
/* If LWORK = -1, then a workspace query is assumed; the routine */
/* only calculates the optimal sizes of the WORK, RWORK and */
/* IWORK arrays, returns these values as the first entries of */
/* the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* RWORK (workspace/output) REAL array, */
/* dimension (LRWORK) */
/* On exit, if INFO = 0, RWORK(1) returns the optimal LRWORK. */
/* LRWORK (input) INTEGER */
/* The dimension of the array RWORK. */
/* If N <= 1, LRWORK must be at least 1. */
/* If JOBZ = 'N' and N > 1, LRWORK must be at least N. */
/* If JOBZ = 'V' and N > 1, LRWORK must be at least */
/* 1 + 5*N + 2*N**2. */
/* If LRWORK = -1, then a workspace query is assumed; the */
/* routine only calculates the optimal sizes of the WORK, RWORK */
/* and IWORK arrays, returns these values as the first entries */
/* of the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* IWORK (workspace/output) INTEGER array, dimension (MAX(1,LIWORK)) */
/* On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK. */
/* LIWORK (input) INTEGER */
/* The dimension of the array IWORK. */
/* If N <= 1, LIWORK must be at least 1. */
/* If JOBZ = 'N' and N > 1, LIWORK must be at least 1. */
/* If JOBZ = 'V' and N > 1, LIWORK must be at least 3 + 5*N. */
/* If LIWORK = -1, then a workspace query is assumed; the */
/* routine only calculates the optimal sizes of the WORK, RWORK */
/* and IWORK arrays, returns these values as the first entries */
/* of the WORK, RWORK and IWORK arrays, and no error message */
/* related to LWORK or LRWORK or LIWORK is issued by XERBLA. */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: if INFO = i and JOBZ = 'N', then the algorithm failed */
/* to converge; i off-diagonal elements of an intermediate */
/* tridiagonal form did not converge to zero; */
/* if INFO = i and JOBZ = 'V', then the algorithm failed */
/* to compute an eigenvalue while working on the submatrix */
/* lying in rows and columns INFO/(N+1) through */
/* mod(INFO,N+1). */
/* Further Details */
/* =============== */
/* Based on contributions by */
/* Jeff Rutter, Computer Science Division, University of California */
/* at Berkeley, USA */
/* Modified description of INFO. Sven, 16 Feb 05. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
--work;
--rwork;
--iwork;
/* Function Body */
wantz = lsame_(jobz, "V");
lower = lsame_(uplo, "L");
lquery = *lwork == -1 || *lrwork == -1 || *liwork == -1;
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -2;
} else if (*n < 0) {
*info = -3;
} else if (*lda < max(1,*n)) {
*info = -5;
}
if (*info == 0) {
if (*n <= 1) {
lwmin = 1;
lrwmin = 1;
liwmin = 1;
lopt = lwmin;
lropt = lrwmin;
liopt = liwmin;
} else {
if (wantz) {
lwmin = (*n << 1) + *n * *n;
/* Computing 2nd power */
i__1 = *n;
lrwmin = *n * 5 + 1 + (i__1 * i__1 << 1);
liwmin = *n * 5 + 3;
} else {
lwmin = *n + 1;
lrwmin = *n;
liwmin = 1;
}
/* Computing MAX */
i__1 = lwmin, i__2 = *n + ilaenv_(&c__1, "CHETRD", uplo, n, &c_n1,
&c_n1, &c_n1);
lopt = max(i__1,i__2);
lropt = lrwmin;
liopt = liwmin;
}
work[1].r = (real) lopt, work[1].i = 0.f;
rwork[1] = (real) lropt;
iwork[1] = liopt;
if (*lwork < lwmin && ! lquery) {
*info = -8;
} else if (*lrwork < lrwmin && ! lquery) {
*info = -10;
} else if (*liwork < liwmin && ! lquery) {
*info = -12;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CHEEVD", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
if (*n == 0) {
return 0;
}
if (*n == 1) {
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
if (wantz) {
i__1 = a_dim1 + 1;
a[i__1].r = 1.f, a[i__1].i = 0.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
rmax = sqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = clanhe_("M", uplo, n, &a[a_offset], lda, &rwork[1]);
iscale = 0;
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
clascl_(uplo, &c__0, &c__0, &c_b18, &sigma, n, n, &a[a_offset], lda,
info);
}
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
inde = 1;
indtau = 1;
indwrk = indtau + *n;
indrwk = inde + *n;
indwk2 = indwrk + *n * *n;
llwork = *lwork - indwrk + 1;
llwrk2 = *lwork - indwk2 + 1;
llrwk = *lrwork - indrwk + 1;
chetrd_(uplo, n, &a[a_offset], lda, &w[1], &rwork[inde], &work[indtau], &
work[indwrk], &llwork, &iinfo);
/* For eigenvalues only, call SSTERF. For eigenvectors, first call */
/* CSTEDC to generate the eigenvector matrix, WORK(INDWRK), of the */
/* tridiagonal matrix, then call CUNMTR to multiply it to the */
/* Householder transformations represented as Householder vectors in */
/* A. */
if (! wantz) {
ssterf_(n, &w[1], &rwork[inde], info);
} else {
cstedc_("I", n, &w[1], &rwork[inde], &work[indwrk], n, &work[indwk2],
&llwrk2, &rwork[indrwk], &llrwk, &iwork[1], liwork, info);
cunmtr_("L", uplo, "N", n, n, &a[a_offset], lda, &work[indtau], &work[
indwrk], n, &work[indwk2], &llwrk2, &iinfo);
clacpy_("A", n, n, &work[indwrk], n, &a[a_offset], lda);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1) {
if (*info == 0) {
imax = *n;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
work[1].r = (real) lopt, work[1].i = 0.f;
rwork[1] = (real) lropt;
iwork[1] = liopt;
return 0;
/* End of CHEEVD */
} /* cheevd_ */
int main(void)
{
/* Local scalars */
char uplo, uplo_i;
lapack_int n, n_i;
lapack_int lda, lda_i;
lapack_int lda_r;
lapack_int lwork, lwork_i;
lapack_int info, info_i;
lapack_int i;
int failed;
/* Local arrays */
lapack_complex_float *a = NULL, *a_i = NULL;
float *d = NULL, *d_i = NULL;
float *e = NULL, *e_i = NULL;
lapack_complex_float *tau = NULL, *tau_i = NULL;
lapack_complex_float *work = NULL, *work_i = NULL;
lapack_complex_float *a_save = NULL;
float *d_save = NULL;
float *e_save = NULL;
lapack_complex_float *tau_save = NULL;
lapack_complex_float *a_r = NULL;
/* Iniitialize the scalar parameters */
init_scalars_chetrd( &uplo, &n, &lda, &lwork );
lda_r = n+2;
uplo_i = uplo;
n_i = n;
lda_i = lda;
lwork_i = lwork;
/* Allocate memory for the LAPACK routine arrays */
a = (lapack_complex_float *)
LAPACKE_malloc( lda*n * sizeof(lapack_complex_float) );
d = (float *)LAPACKE_malloc( n * sizeof(float) );
e = (float *)LAPACKE_malloc( (n-1) * sizeof(float) );
tau = (lapack_complex_float *)
LAPACKE_malloc( (n-1) * sizeof(lapack_complex_float) );
work = (lapack_complex_float *)
LAPACKE_malloc( lwork * sizeof(lapack_complex_float) );
/* Allocate memory for the C interface function arrays */
a_i = (lapack_complex_float *)
LAPACKE_malloc( lda*n * sizeof(lapack_complex_float) );
d_i = (float *)LAPACKE_malloc( n * sizeof(float) );
e_i = (float *)LAPACKE_malloc( (n-1) * sizeof(float) );
tau_i = (lapack_complex_float *)
LAPACKE_malloc( (n-1) * sizeof(lapack_complex_float) );
work_i = (lapack_complex_float *)
LAPACKE_malloc( lwork * sizeof(lapack_complex_float) );
/* Allocate memory for the backup arrays */
a_save = (lapack_complex_float *)
LAPACKE_malloc( lda*n * sizeof(lapack_complex_float) );
d_save = (float *)LAPACKE_malloc( n * sizeof(float) );
e_save = (float *)LAPACKE_malloc( (n-1) * sizeof(float) );
tau_save = (lapack_complex_float *)
LAPACKE_malloc( (n-1) * sizeof(lapack_complex_float) );
/* Allocate memory for the row-major arrays */
a_r = (lapack_complex_float *)
LAPACKE_malloc( n*(n+2) * sizeof(lapack_complex_float) );
/* Initialize input arrays */
init_a( lda*n, a );
init_d( n, d );
init_e( (n-1), e );
init_tau( (n-1), tau );
init_work( lwork, work );
/* Backup the ouptut arrays */
for( i = 0; i < lda*n; i++ ) {
a_save[i] = a[i];
}
for( i = 0; i < n; i++ ) {
d_save[i] = d[i];
}
for( i = 0; i < (n-1); i++ ) {
e_save[i] = e[i];
}
for( i = 0; i < (n-1); i++ ) {
tau_save[i] = tau[i];
}
/* Call the LAPACK routine */
chetrd_( &uplo, &n, a, &lda, d, e, tau, work, &lwork, &info );
/* Initialize input data, call the column-major middle-level
* interface to LAPACK routine and check the results */
for( i = 0; i < lda*n; i++ ) {
a_i[i] = a_save[i];
}
for( i = 0; i < n; i++ ) {
d_i[i] = d_save[i];
}
for( i = 0; i < (n-1); i++ ) {
e_i[i] = e_save[i];
}
for( i = 0; i < (n-1); i++ ) {
tau_i[i] = tau_save[i];
}
for( i = 0; i < lwork; i++ ) {
work_i[i] = work[i];
}
info_i = LAPACKE_chetrd_work( LAPACK_COL_MAJOR, uplo_i, n_i, a_i, lda_i,
d_i, e_i, tau_i, work_i, lwork_i );
failed = compare_chetrd( a, a_i, d, d_i, e, e_i, tau, tau_i, info, info_i,
lda, n );
if( failed == 0 ) {
printf( "PASSED: column-major middle-level interface to chetrd\n" );
} else {
printf( "FAILED: column-major middle-level interface to chetrd\n" );
}
/* Initialize input data, call the column-major high-level
* interface to LAPACK routine and check the results */
for( i = 0; i < lda*n; i++ ) {
a_i[i] = a_save[i];
}
for( i = 0; i < n; i++ ) {
d_i[i] = d_save[i];
}
for( i = 0; i < (n-1); i++ ) {
e_i[i] = e_save[i];
}
for( i = 0; i < (n-1); i++ ) {
tau_i[i] = tau_save[i];
}
for( i = 0; i < lwork; i++ ) {
work_i[i] = work[i];
}
info_i = LAPACKE_chetrd( LAPACK_COL_MAJOR, uplo_i, n_i, a_i, lda_i, d_i,
e_i, tau_i );
failed = compare_chetrd( a, a_i, d, d_i, e, e_i, tau, tau_i, info, info_i,
lda, n );
if( failed == 0 ) {
printf( "PASSED: column-major high-level interface to chetrd\n" );
} else {
printf( "FAILED: column-major high-level interface to chetrd\n" );
}
/* Initialize input data, call the row-major middle-level
* interface to LAPACK routine and check the results */
for( i = 0; i < lda*n; i++ ) {
a_i[i] = a_save[i];
}
for( i = 0; i < n; i++ ) {
d_i[i] = d_save[i];
}
for( i = 0; i < (n-1); i++ ) {
e_i[i] = e_save[i];
}
for( i = 0; i < (n-1); i++ ) {
tau_i[i] = tau_save[i];
}
for( i = 0; i < lwork; i++ ) {
work_i[i] = work[i];
}
LAPACKE_cge_trans( LAPACK_COL_MAJOR, n, n, a_i, lda, a_r, n+2 );
info_i = LAPACKE_chetrd_work( LAPACK_ROW_MAJOR, uplo_i, n_i, a_r, lda_r,
d_i, e_i, tau_i, work_i, lwork_i );
LAPACKE_cge_trans( LAPACK_ROW_MAJOR, n, n, a_r, n+2, a_i, lda );
failed = compare_chetrd( a, a_i, d, d_i, e, e_i, tau, tau_i, info, info_i,
lda, n );
if( failed == 0 ) {
printf( "PASSED: row-major middle-level interface to chetrd\n" );
} else {
printf( "FAILED: row-major middle-level interface to chetrd\n" );
}
/* Initialize input data, call the row-major high-level
* interface to LAPACK routine and check the results */
for( i = 0; i < lda*n; i++ ) {
a_i[i] = a_save[i];
}
for( i = 0; i < n; i++ ) {
d_i[i] = d_save[i];
}
for( i = 0; i < (n-1); i++ ) {
e_i[i] = e_save[i];
}
for( i = 0; i < (n-1); i++ ) {
tau_i[i] = tau_save[i];
}
for( i = 0; i < lwork; i++ ) {
work_i[i] = work[i];
}
/* Init row_major arrays */
LAPACKE_cge_trans( LAPACK_COL_MAJOR, n, n, a_i, lda, a_r, n+2 );
info_i = LAPACKE_chetrd( LAPACK_ROW_MAJOR, uplo_i, n_i, a_r, lda_r, d_i,
e_i, tau_i );
LAPACKE_cge_trans( LAPACK_ROW_MAJOR, n, n, a_r, n+2, a_i, lda );
failed = compare_chetrd( a, a_i, d, d_i, e, e_i, tau, tau_i, info, info_i,
lda, n );
if( failed == 0 ) {
printf( "PASSED: row-major high-level interface to chetrd\n" );
} else {
printf( "FAILED: row-major high-level interface to chetrd\n" );
}
/* Release memory */
if( a != NULL ) {
LAPACKE_free( a );
}
if( a_i != NULL ) {
LAPACKE_free( a_i );
}
if( a_r != NULL ) {
LAPACKE_free( a_r );
}
if( a_save != NULL ) {
LAPACKE_free( a_save );
}
if( d != NULL ) {
LAPACKE_free( d );
}
if( d_i != NULL ) {
LAPACKE_free( d_i );
}
if( d_save != NULL ) {
LAPACKE_free( d_save );
}
if( e != NULL ) {
LAPACKE_free( e );
}
if( e_i != NULL ) {
LAPACKE_free( e_i );
}
if( e_save != NULL ) {
LAPACKE_free( e_save );
}
if( tau != NULL ) {
LAPACKE_free( tau );
}
if( tau_i != NULL ) {
LAPACKE_free( tau_i );
}
if( tau_save != NULL ) {
LAPACKE_free( tau_save );
}
if( work != NULL ) {
LAPACKE_free( work );
}
if( work_i != NULL ) {
LAPACKE_free( work_i );
}
return 0;
}
/* Subroutine */ int cheevx_(char *jobz, char *range, char *uplo, integer *n,
complex *a, integer *lda, real *vl, real *vu, integer *il, integer *
iu, real *abstol, integer *m, real *w, complex *z__, integer *ldz,
complex *work, integer *lwork, real *rwork, integer *iwork, integer *
ifail, integer *info)
{
/* System generated locals */
integer a_dim1, a_offset, z_dim1, z_offset, i__1, i__2;
real r__1, r__2;
/* Builtin functions */
double sqrt(doublereal);
/* Local variables */
integer i__, j, nb, jj;
real eps, vll, vuu, tmp1;
integer indd, inde;
real anrm;
integer imax;
real rmin, rmax;
logical test;
integer itmp1, indee;
real sigma;
extern logical lsame_(char *, char *);
integer iinfo;
extern /* Subroutine */ int sscal_(integer *, real *, real *, integer *);
char order[1];
extern /* Subroutine */ int cswap_(integer *, complex *, integer *,
complex *, integer *);
logical lower;
extern /* Subroutine */ int scopy_(integer *, real *, integer *, real *,
integer *);
logical wantz;
extern doublereal clanhe_(char *, char *, integer *, complex *, integer *,
real *);
logical alleig, indeig;
integer iscale, indibl;
logical valeig;
extern doublereal slamch_(char *);
extern /* Subroutine */ int chetrd_(char *, integer *, complex *, integer
*, real *, real *, complex *, complex *, integer *, integer *), csscal_(integer *, real *, complex *, integer *),
clacpy_(char *, integer *, integer *, complex *, integer *,
complex *, integer *);
real safmin;
extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
integer *, integer *);
extern /* Subroutine */ int xerbla_(char *, integer *);
real abstll, bignum;
integer indiwk, indisp, indtau;
extern /* Subroutine */ int cstein_(integer *, real *, real *, integer *,
real *, integer *, integer *, complex *, integer *, real *,
integer *, integer *, integer *);
integer indrwk, indwrk, lwkmin;
extern /* Subroutine */ int csteqr_(char *, integer *, real *, real *,
complex *, integer *, real *, integer *), cungtr_(char *,
integer *, complex *, integer *, complex *, complex *, integer *,
integer *), ssterf_(integer *, real *, real *, integer *),
cunmtr_(char *, char *, char *, integer *, integer *, complex *,
integer *, complex *, complex *, integer *, complex *, integer *,
integer *);
integer nsplit, llwork;
real smlnum;
extern /* Subroutine */ int sstebz_(char *, char *, integer *, real *,
real *, integer *, integer *, real *, real *, real *, integer *,
integer *, real *, integer *, integer *, real *, integer *,
integer *);
integer lwkopt;
logical lquery;
/* -- LAPACK driver routine (version 3.2) -- */
/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/* November 2006 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* CHEEVX computes selected eigenvalues and, optionally, eigenvectors */
/* of a complex Hermitian matrix A. Eigenvalues and eigenvectors can */
/* be selected by specifying either a range of values or a range of */
/* indices for the desired eigenvalues. */
/* Arguments */
/* ========= */
/* JOBZ (input) CHARACTER*1 */
/* = 'N': Compute eigenvalues only; */
/* = 'V': Compute eigenvalues and eigenvectors. */
/* RANGE (input) CHARACTER*1 */
/* = 'A': all eigenvalues will be found. */
/* = 'V': all eigenvalues in the half-open interval (VL,VU] */
/* will be found. */
/* = 'I': the IL-th through IU-th eigenvalues will be found. */
/* UPLO (input) CHARACTER*1 */
/* = 'U': Upper triangle of A is stored; */
/* = 'L': Lower triangle of A is stored. */
/* N (input) INTEGER */
/* The order of the matrix A. N >= 0. */
/* A (input/output) COMPLEX array, dimension (LDA, N) */
/* On entry, the Hermitian matrix A. If UPLO = 'U', the */
/* leading N-by-N upper triangular part of A contains the */
/* upper triangular part of the matrix A. If UPLO = 'L', */
/* the leading N-by-N lower triangular part of A contains */
/* the lower triangular part of the matrix A. */
/* On exit, the lower triangle (if UPLO='L') or the upper */
/* triangle (if UPLO='U') of A, including the diagonal, is */
/* destroyed. */
/* LDA (input) INTEGER */
/* The leading dimension of the array A. LDA >= max(1,N). */
/* VL (input) REAL */
/* VU (input) REAL */
/* If RANGE='V', the lower and upper bounds of the interval to */
/* be searched for eigenvalues. VL < VU. */
/* Not referenced if RANGE = 'A' or 'I'. */
/* IL (input) INTEGER */
/* IU (input) INTEGER */
/* If RANGE='I', the indices (in ascending order) of the */
/* smallest and largest eigenvalues to be returned. */
/* 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. */
/* Not referenced if RANGE = 'A' or 'V'. */
/* ABSTOL (input) REAL */
/* The absolute error tolerance for the eigenvalues. */
/* An approximate eigenvalue is accepted as converged */
/* when it is determined to lie in an interval [a,b] */
/* of width less than or equal to */
/* ABSTOL + EPS * max( |a|,|b| ) , */
/* where EPS is the machine precision. If ABSTOL is less than */
/* or equal to zero, then EPS*|T| will be used in its place, */
/* where |T| is the 1-norm of the tridiagonal matrix obtained */
/* by reducing A to tridiagonal form. */
/* Eigenvalues will be computed most accurately when ABSTOL is */
/* set to twice the underflow threshold 2*SLAMCH('S'), not zero. */
/* If this routine returns with INFO>0, indicating that some */
/* eigenvectors did not converge, try setting ABSTOL to */
/* 2*SLAMCH('S'). */
/* See "Computing Small Singular Values of Bidiagonal Matrices */
/* with Guaranteed High Relative Accuracy," by Demmel and */
/* Kahan, LAPACK Working Note #3. */
/* M (output) INTEGER */
/* The total number of eigenvalues found. 0 <= M <= N. */
/* If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. */
/* W (output) REAL array, dimension (N) */
/* On normal exit, the first M elements contain the selected */
/* eigenvalues in ascending order. */
/* Z (output) COMPLEX array, dimension (LDZ, max(1,M)) */
/* If JOBZ = 'V', then if INFO = 0, the first M columns of Z */
/* contain the orthonormal eigenvectors of the matrix A */
/* corresponding to the selected eigenvalues, with the i-th */
/* column of Z holding the eigenvector associated with W(i). */
/* If an eigenvector fails to converge, then that column of Z */
/* contains the latest approximation to the eigenvector, and the */
/* index of the eigenvector is returned in IFAIL. */
/* If JOBZ = 'N', then Z is not referenced. */
/* Note: the user must ensure that at least max(1,M) columns are */
/* supplied in the array Z; if RANGE = 'V', the exact value of M */
/* is not known in advance and an upper bound must be used. */
/* LDZ (input) INTEGER */
/* The leading dimension of the array Z. LDZ >= 1, and if */
/* JOBZ = 'V', LDZ >= max(1,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 length of the array WORK. LWORK >= 1, when N <= 1; */
/* otherwise 2*N. */
/* For optimal efficiency, LWORK >= (NB+1)*N, */
/* where NB is the max of the blocksize for CHETRD and for */
/* CUNMTR as returned by ILAENV. */
/* 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 (7*N) */
/* IWORK (workspace) INTEGER array, dimension (5*N) */
/* IFAIL (output) INTEGER array, dimension (N) */
/* If JOBZ = 'V', then if INFO = 0, the first M elements of */
/* IFAIL are zero. If INFO > 0, then IFAIL contains the */
/* indices of the eigenvectors that failed to converge. */
/* If JOBZ = 'N', then IFAIL is not referenced. */
/* INFO (output) INTEGER */
/* = 0: successful exit */
/* < 0: if INFO = -i, the i-th argument had an illegal value */
/* > 0: if INFO = i, then i eigenvectors failed to converge. */
/* Their indices are stored in array IFAIL. */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. Local Scalars .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. Intrinsic Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Test the input parameters. */
/* Parameter adjustments */
a_dim1 = *lda;
a_offset = 1 + a_dim1;
a -= a_offset;
--w;
z_dim1 = *ldz;
z_offset = 1 + z_dim1;
z__ -= z_offset;
--work;
--rwork;
--iwork;
--ifail;
/* Function Body */
lower = lsame_(uplo, "L");
wantz = lsame_(jobz, "V");
alleig = lsame_(range, "A");
valeig = lsame_(range, "V");
indeig = lsame_(range, "I");
lquery = *lwork == -1;
*info = 0;
if (! (wantz || lsame_(jobz, "N"))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || lsame_(uplo, "U"))) {
*info = -3;
} else if (*n < 0) {
*info = -4;
} else if (*lda < max(1,*n)) {
*info = -6;
} else {
if (valeig) {
if (*n > 0 && *vu <= *vl) {
*info = -8;
}
} else if (indeig) {
if (*il < 1 || *il > max(1,*n)) {
*info = -9;
} else if (*iu < min(*n,*il) || *iu > *n) {
*info = -10;
}
}
}
if (*info == 0) {
if (*ldz < 1 || wantz && *ldz < *n) {
*info = -15;
}
}
if (*info == 0) {
if (*n <= 1) {
lwkmin = 1;
work[1].r = (real) lwkmin, work[1].i = 0.f;
} else {
lwkmin = *n << 1;
nb = ilaenv_(&c__1, "CHETRD", uplo, n, &c_n1, &c_n1, &c_n1);
/* Computing MAX */
i__1 = nb, i__2 = ilaenv_(&c__1, "CUNMTR", uplo, n, &c_n1, &c_n1,
&c_n1);
nb = max(i__1,i__2);
/* Computing MAX */
i__1 = 1, i__2 = (nb + 1) * *n;
lwkopt = max(i__1,i__2);
work[1].r = (real) lwkopt, work[1].i = 0.f;
}
if (*lwork < lwkmin && ! lquery) {
*info = -17;
}
}
if (*info != 0) {
i__1 = -(*info);
xerbla_("CHEEVX", &i__1);
return 0;
} else if (lquery) {
return 0;
}
/* Quick return if possible */
*m = 0;
if (*n == 0) {
return 0;
}
if (*n == 1) {
if (alleig || indeig) {
*m = 1;
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
} else if (valeig) {
i__1 = a_dim1 + 1;
i__2 = a_dim1 + 1;
if (*vl < a[i__1].r && *vu >= a[i__2].r) {
*m = 1;
i__1 = a_dim1 + 1;
w[1] = a[i__1].r;
}
}
if (wantz) {
i__1 = z_dim1 + 1;
z__[i__1].r = 1.f, z__[i__1].i = 0.f;
}
return 0;
}
/* Get machine constants. */
safmin = slamch_("Safe minimum");
eps = slamch_("Precision");
smlnum = safmin / eps;
bignum = 1.f / smlnum;
rmin = sqrt(smlnum);
/* Computing MIN */
r__1 = sqrt(bignum), r__2 = 1.f / sqrt(sqrt(safmin));
rmax = dmin(r__1,r__2);
/* Scale matrix to allowable range, if necessary. */
iscale = 0;
abstll = *abstol;
if (valeig) {
vll = *vl;
vuu = *vu;
}
anrm = clanhe_("M", uplo, n, &a[a_offset], lda, &rwork[1]);
if (anrm > 0.f && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
if (lower) {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
i__2 = *n - j + 1;
csscal_(&i__2, &sigma, &a[j + j * a_dim1], &c__1);
/* L10: */
}
} else {
i__1 = *n;
for (j = 1; j <= i__1; ++j) {
csscal_(&j, &sigma, &a[j * a_dim1 + 1], &c__1);
/* L20: */
}
}
if (*abstol > 0.f) {
abstll = *abstol * sigma;
}
if (valeig) {
vll = *vl * sigma;
vuu = *vu * sigma;
}
}
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
indd = 1;
inde = indd + *n;
indrwk = inde + *n;
indtau = 1;
indwrk = indtau + *n;
llwork = *lwork - indwrk + 1;
chetrd_(uplo, n, &a[a_offset], lda, &rwork[indd], &rwork[inde], &work[
indtau], &work[indwrk], &llwork, &iinfo);
/* If all eigenvalues are desired and ABSTOL is less than or equal to */
/* zero, then call SSTERF or CUNGTR and CSTEQR. If this fails for */
/* some eigenvalue, then try SSTEBZ. */
test = FALSE_;
if (indeig) {
if (*il == 1 && *iu == *n) {
test = TRUE_;
}
}
if ((alleig || test) && *abstol <= 0.f) {
scopy_(n, &rwork[indd], &c__1, &w[1], &c__1);
indee = indrwk + (*n << 1);
if (! wantz) {
i__1 = *n - 1;
scopy_(&i__1, &rwork[inde], &c__1, &rwork[indee], &c__1);
ssterf_(n, &w[1], &rwork[indee], info);
} else {
clacpy_("A", n, n, &a[a_offset], lda, &z__[z_offset], ldz);
cungtr_(uplo, n, &z__[z_offset], ldz, &work[indtau], &work[indwrk]
, &llwork, &iinfo);
i__1 = *n - 1;
scopy_(&i__1, &rwork[inde], &c__1, &rwork[indee], &c__1);
csteqr_(jobz, n, &w[1], &rwork[indee], &z__[z_offset], ldz, &
rwork[indrwk], info);
if (*info == 0) {
i__1 = *n;
for (i__ = 1; i__ <= i__1; ++i__) {
ifail[i__] = 0;
/* L30: */
}
}
}
if (*info == 0) {
*m = *n;
goto L40;
}
*info = 0;
}
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, CSTEIN. */
if (wantz) {
*(unsigned char *)order = 'B';
} else {
*(unsigned char *)order = 'E';
}
indibl = 1;
indisp = indibl + *n;
indiwk = indisp + *n;
sstebz_(range, order, n, &vll, &vuu, il, iu, &abstll, &rwork[indd], &
rwork[inde], m, &nsplit, &w[1], &iwork[indibl], &iwork[indisp], &
rwork[indrwk], &iwork[indiwk], info);
if (wantz) {
cstein_(n, &rwork[indd], &rwork[inde], m, &w[1], &iwork[indibl], &
iwork[indisp], &z__[z_offset], ldz, &rwork[indrwk], &iwork[
indiwk], &ifail[1], info);
/* Apply unitary matrix used in reduction to tridiagonal */
/* form to eigenvectors returned by CSTEIN. */
cunmtr_("L", uplo, "N", n, m, &a[a_offset], lda, &work[indtau], &z__[
z_offset], ldz, &work[indwrk], &llwork, &iinfo);
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
L40:
if (iscale == 1) {
if (*info == 0) {
imax = *m;
} else {
imax = *info - 1;
}
r__1 = 1.f / sigma;
sscal_(&imax, &r__1, &w[1], &c__1);
}
/* If eigenvalues are not in order, then sort them, along with */
/* eigenvectors. */
if (wantz) {
i__1 = *m - 1;
for (j = 1; j <= i__1; ++j) {
i__ = 0;
tmp1 = w[j];
i__2 = *m;
for (jj = j + 1; jj <= i__2; ++jj) {
if (w[jj] < tmp1) {
i__ = jj;
tmp1 = w[jj];
}
/* L50: */
}
if (i__ != 0) {
itmp1 = iwork[indibl + i__ - 1];
w[i__] = w[j];
iwork[indibl + i__ - 1] = iwork[indibl + j - 1];
w[j] = tmp1;
iwork[indibl + j - 1] = itmp1;
cswap_(n, &z__[i__ * z_dim1 + 1], &c__1, &z__[j * z_dim1 + 1],
&c__1);
if (*info != 0) {
itmp1 = ifail[i__];
ifail[i__] = ifail[j];
ifail[j] = itmp1;
}
}
/* L60: */
}
}
/* Set WORK(1) to optimal complex workspace size. */
work[1].r = (real) lwkopt, work[1].i = 0.f;
return 0;
/* End of CHEEVX */
} /* cheevx_ */
