/**
Purpose
-------
CHEEVDX_GPU 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.
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
---------
@param[in]
jobz magma_vec_t
- = MagmaNoVec: Compute eigenvalues only;
- = MagmaVec: Compute eigenvalues and eigenvectors.
@param[in]
range magma_range_t
- = MagmaRangeAll: all eigenvalues will be found.
- = MagmaRangeV: all eigenvalues in the half-open interval (VL,VU]
will be found.
- = MagmaRangeI: the IL-th through IU-th eigenvalues will be found.
@param[in]
uplo magma_uplo_t
- = MagmaUpper: Upper triangle of A is stored;
- = MagmaLower: Lower triangle of A is stored.
@param[in]
n INTEGER
The order of the matrix A. N >= 0.
@param[in,out]
dA COMPLEX array on the GPU,
dimension (LDDA, N).
On entry, the Hermitian matrix A. If UPLO = MagmaUpper, the
leading N-by-N upper triangular part of A contains the
upper triangular part of the matrix A. If UPLO = MagmaLower,
the leading N-by-N lower triangular part of A contains
the lower triangular part of the matrix A.
On exit, if JOBZ = MagmaVec, then if INFO = 0, the first m columns
of A contains the required
orthonormal eigenvectors of the matrix A.
If JOBZ = MagmaNoVec, then on exit the lower triangle (if UPLO=MagmaLower)
or the upper triangle (if UPLO=MagmaUpper) of A, including the
diagonal, is destroyed.
@param[in]
ldda INTEGER
The leading dimension of the array DA. LDDA >= max(1,N).
@param[in]
vl REAL
@param[in]
vu REAL
If RANGE=MagmaRangeV, the lower and upper bounds of the interval to
be searched for eigenvalues. VL < VU.
Not referenced if RANGE = MagmaRangeAll or MagmaRangeI.
@param[in]
il INTEGER
@param[in]
iu INTEGER
If RANGE=MagmaRangeI, 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 = MagmaRangeAll or MagmaRangeV.
@param[out]
m INTEGER
The total number of eigenvalues found. 0 <= M <= N.
If RANGE = MagmaRangeAll, M = N, and if RANGE = MagmaRangeI, M = IU-IL+1.
@param[out]
w REAL array, dimension (N)
If INFO = 0, the required m eigenvalues in ascending order.
@param
wA (workspace) COMPLEX array, dimension (LDWA, N)
@param[in]
ldwa INTEGER
The leading dimension of the array wA. LDWA >= max(1,N).
@param[out]
work (workspace) COMPLEX array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK[0] returns the optimal LWORK.
@param[in]
lwork INTEGER
The length of the array WORK.
If N <= 1, LWORK >= 1.
If JOBZ = MagmaNoVec and N > 1, LWORK >= N + N*NB.
If JOBZ = MagmaVec and N > 1, LWORK >= max( N + N*NB, 2*N + N**2 ).
NB can be obtained through magma_get_chetrd_nb(N).
\n
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.
@param[out]
rwork (workspace) REAL array, dimension (LRWORK)
On exit, if INFO = 0, RWORK[0] returns the optimal LRWORK.
@param[in]
lrwork INTEGER
The dimension of the array RWORK.
If N <= 1, LRWORK >= 1.
If JOBZ = MagmaNoVec and N > 1, LRWORK >= N.
If JOBZ = MagmaVec and N > 1, LRWORK >= 1 + 5*N + 2*N**2.
\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.
@param[out]
iwork (workspace) INTEGER array, dimension (MAX(1,LIWORK))
On exit, if INFO = 0, IWORK[0] returns the optimal LIWORK.
@param[in]
liwork INTEGER
The dimension of the array IWORK.
If N <= 1, LIWORK >= 1.
If JOBZ = MagmaNoVec and N > 1, LIWORK >= 1.
If JOBZ = MagmaVec and N > 1, LIWORK >= 3 + 5*N.
\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.
@param[out]
info INTEGER
- = 0: successful exit
- < 0: if INFO = -i, the i-th argument had an illegal value
- > 0: if INFO = i and JOBZ = MagmaNoVec, 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 = MagmaVec, 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.
@ingroup magma_cheev_driver
********************************************************************/
extern "C" magma_int_t
magma_cheevdx_gpu(magma_vec_t jobz, magma_range_t range, magma_uplo_t uplo,
magma_int_t n,
magmaFloatComplex *dA, magma_int_t ldda,
float vl, float vu, magma_int_t il, magma_int_t iu,
magma_int_t *m, float *w,
magmaFloatComplex *wA, magma_int_t ldwa,
magmaFloatComplex *work, magma_int_t lwork,
float *rwork, magma_int_t lrwork,
magma_int_t *iwork, magma_int_t liwork,
magma_int_t *info)
{
const char* uplo_ = lapack_uplo_const( uplo );
const char* jobz_ = lapack_vec_const( jobz );
magma_int_t ione = 1;
float d__1;
float eps;
magma_int_t inde;
float anrm;
magma_int_t imax;
float rmin, rmax;
float sigma;
magma_int_t iinfo, lwmin;
magma_int_t lower;
magma_int_t llrwk;
magma_int_t wantz;
magma_int_t indwk2, llwrk2;
magma_int_t iscale;
float safmin;
float bignum;
magma_int_t indtau;
magma_int_t indrwk, indwrk, liwmin;
magma_int_t lrwmin, llwork;
float smlnum;
magma_int_t lquery;
magma_int_t alleig, valeig, indeig;
float *dwork;
magmaFloatComplex *dC;
magma_int_t lddc = ldda;
wantz = (jobz == MagmaVec);
lower = (uplo == MagmaLower);
alleig = (range == MagmaRangeAll);
valeig = (range == MagmaRangeV);
indeig = (range == MagmaRangeI);
lquery = (lwork == -1 || lrwork == -1 || liwork == -1);
*info = 0;
if (! (wantz || (jobz == MagmaNoVec))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || (uplo == MagmaUpper))) {
*info = -3;
} else if (n < 0) {
*info = -4;
} else if (ldda < max(1,n)) {
*info = -6;
} else if (ldwa < max(1,n)) {
*info = -14;
} 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;
}
}
}
magma_int_t nb = magma_get_chetrd_nb( n );
if ( n <= 1 ) {
lwmin = 1;
lrwmin = 1;
liwmin = 1;
}
else if ( wantz ) {
lwmin = max( n + n*nb, 2*n + n*n );
lrwmin = 1 + 5*n + 2*n*n;
liwmin = 3 + 5*n;
}
else {
lwmin = n + n*nb;
lrwmin = n;
liwmin = 1;
}
// multiply by 1+eps (in Double!) to ensure length gets rounded up,
// if it cannot be exactly represented in floating point.
real_Double_t one_eps = 1. + lapackf77_slamch("Epsilon");
work[0] = MAGMA_C_MAKE( lwmin * one_eps, 0.);
rwork[0] = lrwmin * one_eps;
iwork[0] = liwmin;
if ((lwork < lwmin) && !lquery) {
*info = -16;
} else if ((lrwork < lrwmin) && ! lquery) {
*info = -18;
} else if ((liwork < liwmin) && ! lquery) {
*info = -20;
}
if (*info != 0) {
magma_xerbla( __func__, -(*info));
return *info;
}
else if (lquery) {
return *info;
}
/* Check if matrix is very small then just call LAPACK on CPU, no need for GPU */
if (n <= 128) {
#ifdef ENABLE_DEBUG
printf("--------------------------------------------------------------\n");
printf(" warning matrix too small N=%d NB=%d, calling lapack on CPU \n", (int) n, (int) nb);
printf("--------------------------------------------------------------\n");
#endif
magmaFloatComplex *A;
magma_cmalloc_cpu( &A, n*n );
magma_cgetmatrix(n, n, dA, ldda, A, n);
lapackf77_cheevd(jobz_, uplo_,
&n, A, &n,
w, work, &lwork,
rwork, &lrwork,
iwork, &liwork, info);
magma_csetmatrix( n, n, A, n, dA, ldda);
magma_free_cpu(A);
*m=n;
return *info;
}
magma_queue_t stream;
magma_queue_create( &stream );
// dC and dwork are never used together, so use one buffer for both;
// unfortunately they're different types (complex and float).
// (this works better in dsyevd_gpu where they're both float).
// n*lddc for chetrd2_gpu, *2 for complex
// n for clanhe
magma_int_t ldwork = n*lddc*2;
if ( wantz ) {
// need 3n^2/2 for cstedx
ldwork = max( ldwork, 3*n*(n/2 + 1) );
}
if (MAGMA_SUCCESS != magma_smalloc( &dwork, ldwork )) {
*info = MAGMA_ERR_DEVICE_ALLOC;
return *info;
}
dC = (magmaFloatComplex*) dwork;
/* Get machine constants. */
safmin = lapackf77_slamch("Safe minimum");
eps = lapackf77_slamch("Precision");
smlnum = safmin / eps;
bignum = 1. / smlnum;
rmin = magma_ssqrt(smlnum);
rmax = magma_ssqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = magmablas_clanhe(MagmaMaxNorm, uplo, n, dA, ldda, dwork);
iscale = 0;
sigma = 1;
if (anrm > 0. && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
magmablas_clascl(uplo, 0, 0, 1., sigma, n, n, dA, ldda, info);
}
/* Call CHETRD to reduce Hermitian matrix to tridiagonal form. */
// chetrd rwork: e (n)
// cstedx rwork: e (n) + llrwk (1 + 4*N + 2*N**2) ==> 1 + 5n + 2n^2
inde = 0;
indrwk = inde + n;
llrwk = lrwork - indrwk;
// chetrd work: tau (n) + llwork (n*nb) ==> n + n*nb
// cstedx work: tau (n) + z (n^2)
// cunmtr work: tau (n) + z (n^2) + llwrk2 (n or n*nb) ==> 2n + n^2, or n + n*nb + n^2
indtau = 0;
indwrk = indtau + n;
indwk2 = indwrk + n*n;
llwork = lwork - indwrk;
llwrk2 = lwork - indwk2;
magma_timer_t time=0;
timer_start( time );
#ifdef FAST_HEMV
magma_chetrd2_gpu(uplo, n, dA, ldda, w, &rwork[inde],
&work[indtau], wA, ldwa, &work[indwrk], llwork,
dC, n*lddc, &iinfo);
#else
magma_chetrd_gpu (uplo, n, dA, ldda, w, &rwork[inde],
&work[indtau], wA, ldwa, &work[indwrk], llwork, &iinfo);
#endif
timer_stop( time );
timer_printf( "time chetrd_gpu = %6.2f\n", time );
/* 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) {
lapackf77_ssterf(&n, w, &rwork[inde], info);
magma_smove_eig(range, n, w, &il, &iu, vl, vu, m);
}
else {
timer_start( time );
magma_cstedx(range, n, vl, vu, il, iu, w, &rwork[inde],
&work[indwrk], n, &rwork[indrwk],
llrwk, iwork, liwork, dwork, info);
timer_stop( time );
timer_printf( "time cstedx = %6.2f\n", time );
timer_start( time );
magma_smove_eig(range, n, w, &il, &iu, vl, vu, m);
magma_csetmatrix( n, *m, &work[indwrk + n * (il-1) ], n, dC, lddc );
magma_cunmtr_gpu(MagmaLeft, uplo, MagmaNoTrans, n, *m, dA, ldda, &work[indtau],
dC, lddc, wA, ldwa, &iinfo);
magma_ccopymatrix( n, *m, dC, lddc, dA, ldda );
timer_stop( time );
timer_printf( "time cunmtr_gpu + copy = %6.2f\n", time );
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1) {
if (*info == 0) {
imax = n;
} else {
imax = *info - 1;
}
d__1 = 1. / sigma;
blasf77_sscal(&imax, &d__1, w, &ione);
}
work[0] = MAGMA_C_MAKE( lwmin * one_eps, 0.); // round up
rwork[0] = lrwmin * one_eps;
iwork[0] = liwmin;
magma_queue_destroy( stream );
magma_free( dwork );
return *info;
} /* magma_cheevdx_gpu */
/**
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
---------
@param[in]
jobz magma_vec_t
- = MagmaNoVec: Compute eigenvalues only;
- = MagmaVec: Compute eigenvalues and eigenvectors.
@param[in]
range magma_range_t
- = MagmaRangeAll: all eigenvalues will be found.
- = MagmaRangeV: all eigenvalues in the half-open interval (VL,VU]
will be found.
- = MagmaRangeI: the IL-th through IU-th eigenvalues will be found.
@param[in]
uplo magma_uplo_t
- = MagmaUpper: Upper triangle of A is stored;
- = MagmaLower: Lower triangle of A is stored.
@param[in]
n INTEGER
The order of the matrix A. N >= 0.
@param[in,out]
dA COMPLEX array, dimension (LDDA, N)
On entry, the Hermitian matrix A. If UPLO = MagmaUpper, the
leading N-by-N upper triangular part of A contains the
upper triangular part of the matrix A. If UPLO = MagmaLower,
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=MagmaLower) or the upper
triangle (if UPLO=MagmaUpper) of A, including the diagonal, is
destroyed.
@param[in]
ldda INTEGER
The leading dimension of the array DA. LDDA >= max(1,N).
@param[in]
vl REAL
@param[in]
vu REAL
If RANGE=MagmaRangeV, the lower and upper bounds of the interval to
be searched for eigenvalues. VL < VU.
Not referenced if RANGE = MagmaRangeAll or MagmaRangeI.
@param[in]
il INTEGER
@param[in]
iu INTEGER
If RANGE=MagmaRangeI, 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 = MagmaRangeAll or MagmaRangeV.
@param[in]
abstol 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| ),
\n
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.
\n
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').
\n
See "Computing Small Singular Values of Bidiagonal Matrices
with Guaranteed High Relative Accuracy," by Demmel and
Kahan, LAPACK Working Note #3.
@param[out]
m INTEGER
The total number of eigenvalues found. 0 <= M <= N.
If RANGE = MagmaRangeAll, M = N, and if RANGE = MagmaRangeI, M = IU-IL+1.
@param[out]
w REAL array, dimension (N)
On normal exit, the first M elements contain the selected
eigenvalues in ascending order.
@param[out]
dZ COMPLEX array, dimension (LDDZ, max(1,M))
If JOBZ = MagmaVec, 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 = MagmaNoVec, 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 = MagmaRangeV, the exact value of M
is not known in advance and an upper bound must be used.
********* (workspace) If FAST_HEMV is defined DZ should be (LDDZ, max(1,N)) in both cases.
@param[in]
lddz INTEGER
The leading dimension of the array DZ. LDDZ >= 1, and if
JOBZ = MagmaVec, LDDZ >= max(1,N).
@param
wA (workspace) COMPLEX array, dimension (LDWA, N)
@param[in]
ldwa INTEGER
The leading dimension of the array wA. LDWA >= max(1,N).
@param
wZ (workspace) COMPLEX array, dimension (LDWZ, max(1,M))
@param[in]
ldwz INTEGER
The leading dimension of the array wZ. LDWZ >= 1, and if
JOBZ = MagmaVec, LDWZ >= max(1,N).
@param[out]
work (workspace) COMPLEX array, dimension (LWORK)
On exit, if INFO = 0, WORK[0] returns the optimal LWORK.
@param[in]
lwork INTEGER
The length of the array WORK. LWORK >= (NB+1)*N,
where NB is the max of the blocksize for CHETRD.
\n
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.
@param
rwork (workspace) REAL array, dimension (7*N)
@param
iwork (workspace) INTEGER array, dimension (5*N)
@param[out]
ifail INTEGER array, dimension (N)
If JOBZ = MagmaVec, 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 = MagmaNoVec, then IFAIL is not referenced.
@param[out]
info 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.
@ingroup magma_cheev_driver
********************************************************************/
extern "C" magma_int_t
magma_cheevx_gpu(
magma_vec_t jobz, magma_range_t range, magma_uplo_t uplo, magma_int_t n,
magmaFloatComplex_ptr dA, magma_int_t ldda,
float vl, float vu,
magma_int_t il, magma_int_t iu, float abstol, magma_int_t *m,
float *w,
magmaFloatComplex_ptr dZ, magma_int_t lddz,
magmaFloatComplex *wA, magma_int_t ldwa,
magmaFloatComplex *wZ, magma_int_t ldwz,
magmaFloatComplex *work, magma_int_t lwork,
float *rwork, magma_int_t *iwork, magma_int_t *ifail,
magma_int_t *info)
{
const char* uplo_ = lapack_uplo_const( uplo );
const char* jobz_ = lapack_vec_const( jobz );
const char* range_ = lapack_range_const( range );
magma_int_t ione = 1;
const char* order_;
magma_int_t indd, inde;
magma_int_t imax;
magma_int_t lopt, itmp1, indee;
magma_int_t lower, wantz;
magma_int_t i, j, jj, i__1;
magma_int_t alleig, valeig, indeig;
magma_int_t iscale, indibl;
magma_int_t indiwk, indisp, indtau;
magma_int_t indrwk, indwrk;
magma_int_t llwork, nsplit;
magma_int_t lquery;
magma_int_t iinfo;
float safmin;
float bignum;
float smlnum;
float eps, tmp1;
float anrm;
float sigma, d__1;
float rmin, rmax;
magmaFloat_ptr dwork;
/* Function Body */
lower = (uplo == MagmaLower);
wantz = (jobz == MagmaVec);
alleig = (range == MagmaRangeAll);
valeig = (range == MagmaRangeV);
indeig = (range == MagmaRangeI);
lquery = (lwork == -1);
*info = 0;
if (! (wantz || (jobz == MagmaNoVec))) {
*info = -1;
} else if (! (alleig || valeig || indeig)) {
*info = -2;
} else if (! (lower || (uplo == MagmaUpper))) {
*info = -3;
} else if (n < 0) {
*info = -4;
} else if (ldda < max(1,n)) {
*info = -6;
} else if (lddz < 1 || (wantz && lddz < n)) {
*info = -15;
} else if (ldwa < max(1,n)) {
*info = -17;
} else if (ldwz < 1 || (wantz && ldwz < n)) {
*info = -19;
} 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;
}
}
}
magma_int_t nb = magma_get_chetrd_nb(n);
lopt = n * (nb + 1);
work[0] = MAGMA_C_MAKE( lopt, 0 );
if (lwork < lopt && ! lquery) {
*info = -21;
}
if (*info != 0) {
magma_xerbla( __func__, -(*info));
return *info;
} else if (lquery) {
return *info;
}
*m = 0;
/* Check if matrix is very small then just call LAPACK on CPU, no need for GPU */
if (n <= 128) {
#ifdef ENABLE_DEBUG
printf("--------------------------------------------------------------\n");
printf(" warning matrix too small N=%d NB=%d, calling lapack on CPU \n", (int) n, (int) nb);
printf("--------------------------------------------------------------\n");
#endif
magmaFloatComplex *a;
magma_cmalloc_cpu( &a, n*n );
magma_cgetmatrix(n, n, dA, ldda, a, n);
lapackf77_cheevx(jobz_, range_, uplo_,
&n, a, &n, &vl, &vu, &il, &iu, &abstol, m,
w, wZ, &ldwz, work, &lwork,
rwork, iwork, ifail, info);
magma_csetmatrix( n, n, a, n, dA, ldda);
magma_csetmatrix( n, *m, wZ, ldwz, dZ, lddz);
magma_free_cpu(a);
return *info;
}
if (MAGMA_SUCCESS != magma_smalloc( &dwork, n )) {
fprintf (stderr, "!!!! device memory allocation error (magma_cheevx_gpu)\n");
*info = MAGMA_ERR_DEVICE_ALLOC;
return *info;
}
--w;
--work;
--rwork;
--iwork;
--ifail;
/* Get machine constants. */
safmin = lapackf77_slamch("Safe minimum");
eps = lapackf77_slamch("Precision");
smlnum = safmin / eps;
bignum = 1. / smlnum;
rmin = magma_ssqrt(smlnum);
rmax = magma_ssqrt(bignum);
/* Scale matrix to allowable range, if necessary. */
anrm = magmablas_clanhe(MagmaMaxNorm, uplo, n, dA, ldda, dwork);
iscale = 0;
sigma = 1;
if (anrm > 0. && anrm < rmin) {
iscale = 1;
sigma = rmin / anrm;
} else if (anrm > rmax) {
iscale = 1;
sigma = rmax / anrm;
}
if (iscale == 1) {
d__1 = 1.;
magmablas_clascl(uplo, 0, 0, 1., sigma, n, n, dA,
ldda, info);
if (abstol > 0.) {
abstol *= sigma;
}
if (valeig) {
vl *= sigma;
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;
#ifdef FAST_HEMV
magma_chetrd2_gpu(uplo, n, dA, ldda, &rwork[indd], &rwork[inde],
&work[indtau], wA, ldwa, &work[indwrk], llwork, dZ, lddz*n, &iinfo);
#else
magma_chetrd_gpu (uplo, n, dA, ldda, &rwork[indd], &rwork[inde],
&work[indtau], wA, ldwa, &work[indwrk], llwork, &iinfo);
#endif
lopt = n + (magma_int_t)MAGMA_C_REAL(work[indwrk]);
/* 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. */
if ((alleig || (indeig && il == 1 && iu == n)) && abstol <= 0.) {
blasf77_scopy(&n, &rwork[indd], &ione, &w[1], &ione);
indee = indrwk + 2*n;
if (! wantz) {
i__1 = n - 1;
blasf77_scopy(&i__1, &rwork[inde], &ione, &rwork[indee], &ione);
lapackf77_ssterf(&n, &w[1], &rwork[indee], info);
}
else {
lapackf77_clacpy("A", &n, &n, wA, &ldwa, wZ, &ldwz);
lapackf77_cungtr(uplo_, &n, wZ, &ldwz, &work[indtau], &work[indwrk], &llwork, &iinfo);
i__1 = n - 1;
blasf77_scopy(&i__1, &rwork[inde], &ione, &rwork[indee], &ione);
lapackf77_csteqr(jobz_, &n, &w[1], &rwork[indee], wZ, &ldwz, &rwork[indrwk], info);
if (*info == 0) {
for (i = 1; i <= n; ++i) {
ifail[i] = 0;
}
magma_csetmatrix( n, n, wZ, ldwz, dZ, lddz );
}
}
if (*info == 0) {
*m = n;
}
}
/* Otherwise, call SSTEBZ and, if eigenvectors are desired, CSTEIN. */
if (*m == 0) {
*info = 0;
if (wantz) {
order_ = "B";
} else {
order_ = "E";
}
indibl = 1;
indisp = indibl + n;
indiwk = indisp + n;
lapackf77_sstebz(range_, order_, &n, &vl, &vu, &il, &iu, &abstol, &rwork[indd], &rwork[inde], m,
&nsplit, &w[1], &iwork[indibl], &iwork[indisp], &rwork[indrwk], &iwork[indiwk], info);
if (wantz) {
lapackf77_cstein(&n, &rwork[indd], &rwork[inde], m, &w[1], &iwork[indibl], &iwork[indisp],
wZ, &ldwz, &rwork[indrwk], &iwork[indiwk], &ifail[1], info);
magma_csetmatrix( n, *m, wZ, ldwz, dZ, lddz );
/* Apply unitary matrix used in reduction to tridiagonal
form to eigenvectors returned by CSTEIN. */
magma_cunmtr_gpu(MagmaLeft, uplo, MagmaNoTrans, n, *m, dA, ldda, &work[indtau],
dZ, lddz, wA, ldwa, &iinfo);
}
}
/* If matrix was scaled, then rescale eigenvalues appropriately. */
if (iscale == 1) {
if (*info == 0) {
imax = *m;
} else {
imax = *info - 1;
}
d__1 = 1. / sigma;
blasf77_sscal(&imax, &d__1, &w[1], &ione);
}
/* If eigenvalues are not in order, then sort them, along with
eigenvectors. */
if (wantz) {
for (j = 1; j <= *m-1; ++j) {
i = 0;
tmp1 = w[j];
for (jj = j + 1; jj <= *m; ++jj) {
if (w[jj] < tmp1) {
i = jj;
tmp1 = w[jj];
}
}
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;
magma_cswap(n, dZ + (i-1)*lddz, ione, dZ + (j-1)*lddz, ione);
if (*info != 0) {
itmp1 = ifail[i];
ifail[i] = ifail[j];
ifail[j] = itmp1;
}
}
}
}
/* Set WORK[0] to optimal complex workspace size. */
work[1] = MAGMA_C_MAKE( lopt, 0 );
return *info;
} /* magma_cheevx_gpu */
