PLASMA  2.8.0
PLASMA - Parallel Linear Algebra for Scalable Multi-core Architectures
int PLASMA_dsytrd ( PLASMA_enum  jobz,
PLASMA_enum  uplo,
int  N,
double *  A,
int  LDA,
double *  D,
double *  E,
PLASMA_desc descT,
double *  Q,
int  LDQ 
)

PLASMA_dsytrd - reduces a complex Hermitian matrix A to real symmetric tridiagonal form S using a two-stage approach First stage: reduction to band tridiagonal form (unitary Q1); Second stage: reduction from band to tridiagonal form (unitary Q2). Let Q = Q1 * Q2 be the global unitary transformation; Q**T * A * Q = S.

Parameters
[in]jobzIntended usage: = PlasmaNoVec: computes tridiagonal only; = PlasmaVec: computes tridiagonal and generate the orthogonal matrix Q.
[in]uploSpecifies whether the matrix A is upper triangular or lower triangular: = PlasmaUpper: Upper triangle of A is stored; = PlasmaLower: Lower triangle of A is stored.
[in]NThe order of the matrix A. N >= 0.
[in,out]AOn entry, the symmetric (or Hermitian) matrix A. If uplo = PlasmaUpper, the leading N-by-N upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If uplo = PlasmaLower, the leading N-by-N lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced. On exit, the lower triangle (if uplo = PlasmaLower) or the upper triangle (if uplo = PlasmaUpper) of A, including the diagonal, is destroyed.
[in]LDAThe leading dimension of the array A. LDA >= max(1,N).
[out]DOn exit, the diagonal elements of the tridiagonal matrix: D(i) = A(i,i).
[out]EOn exit, he off-diagonal elements of the tridiagonal matrix: E(i) = A(i,i+1) if uplo = PlasmaUpper, E(i) = A(i+1,i) if uplo = PlasmaLower.
[out]descTOn entry, descriptor as return by PLASMA_Alloc_Workspace_dsytrd On exit, contains auxiliary factorization data.
[out]QOn exit, if jobz = PlasmaVec, then if return value = 0, Q contains the N-by-N unitary matrix Q. If jobz = PlasmaNoVec, then it is not referenced.
[in]LDQThe leading dimension of the array Q. LDQ >= N.
Returns
Return values
PLASMA_SUCCESSsuccessful exit
<0if -i, the i-th argument had an illegal value
>0if INFO = i, the algorithm failed to converge; i off-diagonal elements of an intermediate tridiagonal form did not converge to zero.
See also
PLASMA_dsytrd_Tile
PLASMA_dsytrd_Tile_Async
PLASMA_chetrd
PLASMA_dsytrd
PLASMA_ssytrd