ZUNGQL(3)

💅 NAME 💅

okay bestie, this page is zungql.f(3) from the Library Functions Manual — yes, the manual name is folded in right here at the top, periodt.

The NAME block is literally just this absolute path, and we are keeping it exactly:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zungql.f

✨ SYNOPSIS ✨

🌸 Functions/Subroutines 🌸

subroutine ZUNGQL (m, n, k, a, lda, tau, work, lwork, info)
    ZUNGQL

🦋 Function/Subroutine Documentation 🦋

Here’s the full signature, no cap, character for character:

subroutine ZUNGQL (integer m, integer n, integer k, complex*16, dimension( lda, * ) a, integer lda, complex*16, dimension( * ) tau, complex*16, dimension( * ) work, integer lwork, integer info)
    ZUNGQL

ZUNGQL is the subroutine in question. Slay.

🔥 Purpose 🔥

ZUNGQL generates an M-by-N complex matrix Q with orthonormal columns, which is defined as the last N columns of a product of K elementary reflectors of order M

Q  =  H(k) . . . H(2) H(1)

as returned by ZGEQLF.

🎀 Parameters 🎀

okay bestie, here’s every parameter, and we are not skipping a single one, fr fr.

💜 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. M >= N >= 0.

💜 K

K is INTEGER. The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.

💜 A

A is COMPLEX*16 array, dimension (LDA,N).

On entry, the (n-k+i)-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by ZGEQLF in the last k columns 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*16 array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZGEQLF.

💜 WORK

WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)).

On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

💜 LWORK

LWORK is INTEGER. The dimension of the array WORK. LWORK >= max(1,N).

For optimum performance LWORK >= N*NB, 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

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 127 of file zungql.f.

💖 Author 💖

Generated automatically by Doxygen for LAPACK from the source code.

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okay that’s the whole page, bestie 💖. The footer energy is LAPACK Version 3.12.0 and /home/abui...RC/zungql.f(3) — that’s the cute sign-off, no cap. bye! 🫶✨