Dgelqf Dgeqp3 Dgeqrf Dorglq Dorgqr Dormlq Dormqr

Dorgqr() Sub Dorgqr ( M As  Long, N As  Long, K As  Long, A() As  Double, Tau() As  Double, Info As  Long  ) Generates matrix Q of QR factorization Purpose This routine generates an m x n real matrix Q with orthonormal columns, which is defined as the first n columns of a product of k elementary reflectors of order m Q = H(1) H(2) . . . H(k) as returned by Dgeqrf. Parameters [in] M Number of rows of the matrix A. (M >= 0) (If M = 0, returns without computation) [in] N Number of columns of the matrix A. (M >= N >= 0) (If N = 0, returns without computation) [in] K Number of elementary reflectors whose product defines the matrix Q. (N >= K >= 0) [in,out] A() Array A(LA1 - 1, LA2 - 1) (LA1 >= M, LA2 >= N) [in] The i-th column must contain the vector which defines the elementary reflector H(i), for i = 1, 2, ..., K, as returned by Dgeqrf in the first K columns of its array argument A(). [out] M x N matrix Q. [in] Tau() Array Tau(LTau - 1) (LTau >= K) The scalar factors of the elementary reflectors H(i) as returned by Dgeqrf. [out] Info = 0: Successful exit. = -1: The argument M had an illegal value. (M < 0) = -2: The argument N had an illegal value. (N < 0 or N > M) = -3: The argument K had an illegal value. (K < 0 or K > N) = -4: The argument A() is invalid. = -5: The argument Tau() is invalid. Reference LAPACK Example Program See example of Dgeqrf and Dgeqp3.