SRC/cungr2.f(3)

✨ SRC/cungr2.f(3) ✨

okay bestie, this is the Library Functions Manual page for SRC/cungr2.f(3). It's giving LAPACK subroutine energy, and it's lowkey iconic. 🦋

💖 NAME 💖

SRC/cungr2.f

✨ SYNOPSIS ✨

🛠️ Functions/Subroutines 🛠️

• subroutine cungr2 (m, n, k, a, lda, tau, work, info) — bestie, CUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm). ✨

🌟 Function/Subroutine Documentation 🌟

subroutine cungr2 (integer m, integer n, integer k, complex, dimension( lda,
* ) a, integer lda, complex, dimension( * ) tau, complex, dimension( * )
work, integer info)

CUNGR2 generates all or part of the unitary matrix Q from an RQ factorization determined by cgerqf (unblocked algorithm).

🎯 Purpose 🎯

!>
!> CUNGR2 generates an m by n complex matrix Q with orthonormal rows,
!> which is defined as the last m rows of a product of k elementary
!> reflectors of order n
!>
!>       Q  =  H(1)**H H(2)**H . . . H(k)**H
!>
!> as returned by CGERQF.
!>

🧸 Parameters 🧸

• M — M is INTEGER; the number of rows of the matrix Q. M >= 0.
• N — N is INTEGER; the number of columns of the matrix Q. N >= M.
• K — K is INTEGER; the number of elementary reflectors whose product defines the matrix Q. M >= K >= 0.
• A — A is COMPLEX array, dimension (LDA,N). On entry, the (m-k+i)-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGERQF in the last k rows of its array argument A. On exit, the m-by-n matrix Q.
• LDA — LDA is INTEGER; the first dimension of the array A. LDA >= max(1,M).
• TAU — TAU is COMPLEX array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGERQF.
• WORK — WORK is COMPLEX array, dimension (M).
• INFO — INFO is INTEGER; = 0: successful exit; < 0: if INFO = -i, the i-th argument has an illegal value.

👑 Author 👑

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 113 of file cungr2.f.

💌 Author 💌

Generated automatically by Doxygen for LAPACK from the source code.

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final footer sign-off, bestie: LAPACK Version 3.12.0 on SRC/cungr2.f(3) — that's the source/version line from the footer, and no extra date is printed here, so I'm not inventing one. 💖✨🫶