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template<typename T>
void opgtr(char *uplo, integer *n, T *ap, T *tau, T *q, integer *ldq, T *work, integer *info)# OPGTR generates a real orthogonal matrix Q.
Purpose:
OPGTR generates a real orthogonal matrix Q which is defined as the product of n-1 elementary reflectors H(i) of order n, as returned by SSPTRD using packed storage: if UPLO = 'U', Q = H(n-1) . . . H(2) H(1), if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
- Parameters:
UPLO – [in]
UPLO is CHARACTER*1
= ‘U’: Upper triangular packed storage used in previous call to SSPTRD;
= ‘L’: Lower triangular packed storage used in previous call to SSPTRD.N – [in]
N is INTEGER
The order of the matrix Q. N >= 0.
AP – [in]
AP is REAL array, dimension (N*(N+1)/2)
The vectors which define the elementary reflectors, as returned by SSPTRD.
TAU – [in]
TAU is REAL array, dimension (N-1)
TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by SSPTRD.
Q – [out]
Q is REAL array, dimension (LDQ,N)
The N-by-N orthogonal matrix Q.
LDQ – [in]
LDQ is INTEGER
The leading dimension of the array Q. LDQ >= fla_max(1,N).
WORK – [out] WORK is REAL array, dimension (N-1)
INFO – [out]
INFO is INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value