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template<typename T>
void ormhr(char *side, char *trans, integer *m, integer *n, integer *ilo, integer *ihi, T *a, integer *lda, T *tau, T *c, integer *ldc, T *work, integer *lwork, integer *info)# ORMHR overwrites the general real M-by-N matrix C.
Purpose:
ORMHR overwrites the general real M-by-N matrix C with SIDE = 'L' SIDE = 'R' TRANS = 'N': Q * C C * Q TRANS = 'T': Q**T * C C * Q**T where Q is a real orthogonal matrix of order nq, with nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of IHI-ILO elementary reflectors, as returned by SGEHRD: Q = H(ilo) H(ilo+1) . . . H(ihi-1).
- Parameters:
SIDE – [in]
SIDE is CHARACTER*1
= ‘L’: apply Q or Q**T from the Left;
= ‘R’: apply Q or Q**T from the Right.TRANS – [in]
TRANS is CHARACTER*1
= ‘N’: No transpose, apply Q;
= ‘T’: Transpose, apply Q**T.M – [in]
M is INTEGER
The number of rows of the matrix C. M >= 0.
N – [in]
N is INTEGER
The number of columns of the matrix C. N >= 0.
ILO – [in] ILO is INTEGER
IHI – [in]
IHI is INTEGER
ILO and IHI must have the same values as in the previous call of SGEHRD. Q is equal to the unit matrix except in the submatrix Q(ilo+1:ihi,ilo+1:ihi).
If SIDE = ‘L’, then 1 <= ILO <= IHI <= M, if M > 0, and ILO = 1 and IHI = 0, if M = 0;
if SIDE = ‘R’, then 1 <= ILO <= IHI <= N, if N > 0, and ILO = 1 and IHI = 0, if N = 0.
A – [in]
A is REAL array, dimension
(LDA,M) if SIDE = ‘L’
(LDA,N) if SIDE = ‘R’
The vectors which define the elementary reflectors, as returned by SGEHRD.
LDA – [in]
LDA is INTEGER
The leading dimension of the array A.
LDA >= fla_max(1,M) if SIDE = ‘L’; LDA >= fla_max(1,N) if SIDE = ‘R’.TAU – [in]
TAU is REAL array, dimension
(M-1) if SIDE = ‘L’
(N-1) if SIDE = ‘R’
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SGEHRD.
C – [inout]
C is REAL array, dimension (LDC,N)
On entry, the M-by-N matrix C.
On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.LDC – [in]
LDC is INTEGER
The leading dimension of the array C. LDC >= fla_max(1,M).
WORK – [out]
WORK is REAL array, dimension (MAX(1,LWORK))
On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
LWORK – [in]
LWORK is INTEGER
The dimension of the array WORK.
If SIDE = ‘L’, LWORK >= fla_max(1,N);
if SIDE = ‘R’, LWORK >= fla_max(1,M).
For optimum performance LWORK >= N*NB if SIDE = ‘L’, and LWORK >= M*NB if SIDE = ‘R’, where NB is the optimal blocksize.
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.
INFO – [out]
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value