PLASMA  2.4.6
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int PLASMA_sgebrd ( int  M,
int  N,
float *  A,
int  LDA,
float *  D,
float *  E,
PLASMA_desc descT 
)

PLASMA_sgebrd - 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]MThe number of rows of the matrix A. M >= 0.
[in]NThe number of columns of the matrix A. N >= 0.
[in,out]AOn 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]LDAThe leading dimension of the array A. LDA >= max(1,M).
[out]DOn exit, the diagonal elements of the bidiagonal matrix: D(i) = A(i,i). Dimension (min(M,N)).
[out]EOn 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]descTOn entry, descriptor as return by PLASMA_Alloc_Workspace_sgesvd On exit, contains auxiliary factorization data.
Returns
Return values
PLASMA_SUCCESSsuccessful exit
<0if -i, the i-th argument had an illegal value
See Also
PLASMA_sgebrd_Tile
PLASMA_sgebrd_Tile_Async
PLASMA_cgebrd
PLASMA_dgebrd
PLASMA_sgebrd