PLASMA 2.8.0 PLASMA - Parallel Linear Algebra for Scalable Multi-core Architectures

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int PLASMA_dgebrd | ( | PLASMA_enum | jobq,
|  | PLASMA_enum | jobp,
|  | int | M,
|  | int | N,
|  | double * | A,
|  | int | LDA,
|  | double * | D,
|  | double * | E,
|  | PLASMA_desc * | descT,
|  | double * | Q,
|  | int | LDQ,
|  | double * | P,
|  | int | LDP
| ) |  |

PLASMA_dgebrd - reduces a general complex M-by-N matrix A to upper or lower bidiagonal form B using a two-stage approach First stage: reduction to band bidiagonal form (orthogonal matrices Q1 and P1); Second stage: reduction from band to bidiagonal form (orthogonal matrices Q2 and P2). Let Q = Q1 * Q2 be the global left unitary transformation; Let P = P1 * P2 be the global right unitary transformation; Q**T * A * P = B. If M >= N, B is upper bidiagonal; if M < N, B is lower bidiagonal. Not LAPACK Compliant for now! Note: T is incomplete and contains only the block reflectors of the first stage. Therefore, Q and P can not be built completely.

Parameters

  [in] | jobq | Specifies options for computing all or part of the matrix Q. Intended usage: = PlasmaVec: all M columns of Q are returned in array Q; = PlasmaNoVec: not referenced.
  [in] | jobp | Specifies options for computing all or part of the matrix V**T. Intended usage: = PlasmaVec: all N columns of P are returned in array P; = PlasmaNoVec: not referenced.
  [in] | M | The number of rows of the matrix A. M >= 0.
  [in] | N | The number of columns of the matrix A. N >= 0.
  [in,out] | A | On entry, the M-by-N matrix A. On exit, if M >= N, the diagonal and the first superdiagonal are overwritten with the upper bidiagonal matrix B; the elements below the diagonal, with the array T, represent the unitary matrix Q as a product of elementary reflectors, and the elements above the first superdiagonal, with the array T, represent the unitary matrix P as a product of elementary reflectors; if M < N, the diagonal and the first subdiagonal are overwritten with the lower bidiagonal matrix B; the elements below the first subdiagonal, with the array T, represent the unitary matrix Q as a product of elementary reflectors, and the elements above the diagonal, with the array T, represent the unitary matrix P as a product of elementary reflectors.
  [in] | LDA | The leading dimension of the array A. LDA >= max(1,M).
  [out] | D | On exit, the diagonal elements of the bidiagonal matrix: D(i) = A(i,i). Dimension (min(M,N)).
  [out] | E | On exit, the off-diagonal elements of the bidiagonal matrix: if M >= N, E(i) = A(i,i+1) for i = 1,2,...,N-1; if M < N, E(i) = A(i+1,i) for i = 1,2,...,M-1. Dimension (min(M,N)-1).
  [out] | descT | On entry, descriptor as return by PLASMA_Alloc_Workspace_dgebrd On exit, contains auxiliary factorization data.
  [out] | Q | On exit, if jobz = PlasmaVec, then if return value = 0, Q contains the M-by-M unitary matrix Q. If jobz = PlasmaNoVec, then it is not referenced.
  [in] | LDQ | The leading dimension of the array Q. LDQ >= M.
  [out] | P | On exit, if jobz = PlasmaVec, then if return value = 0, P contains the N-by-N unitary matrix P. If jobz = PlasmaNoVec, then it is not referenced.
  [in] | LDP | The leading dimension of the array P. LDP >= N.

Returns

Return values

  PLASMA_SUCCESS | successful exit
  <0 | if -i, the i-th argument had an illegal value

See also
  PLASMA_dgebrd_Tile
  PLASMA_dgebrd_Tile_Async
  PLASMA_cgebrd
  PLASMA_dgebrd
  PLASMA_sgebrd