XLPack 6.1
Excel VBA Numerical Library Reference Manual
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◆ Zunglq()

Sub Zunglq ( M As  Long,
N As  Long,
K As  Long,
A() As  Complex,
Tau() As  Complex,
Info As  Long 
)

Generates matrix Q of LQ factorization of a complex matrix

Purpose
This routine generates an m x n complex matrix Q with orthonormal rows, which is defined as the first m rows of a product of k elementary reflectors of order n
Q = H(k) . . . H(2) H(1)
as returned by Zgelqf.
Parameters
[in]MNumber of rows of the matrix A. (M >= 0) (If M = 0, returns without computation)
[in]NNumber of columns of the matrix A. (N >= M)
[in]KNumber of elementary reflectors whose product defines the matrix Q. (M >= K >= 0)
[in,out]A()Array A(LA1 - 1, LA2 - 1) (LA1 >= M, LA2 >= N)
[in] The i-th row must contain the vector which defines the elementary reflector H(i), for i = 1, 2, ..., K, as returned by Zgelqf in the first K rows 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 Zgelqf.
[out]Info= 0: Successful exit.
= -1: The argument M had an illegal value. (M < 0)
= -2: The argument N had an illegal value. (N < M)
= -3: The argument K had an illegal value. (K < 0 or K > M)
= -4: The argument A() is invalid.
= -5: The argument Tau() is invalid.
Reference
LAPACK
Example Program
See example of Zgelqf.