SRC/cunmrz.f(3)

💅 SRC/cunmrz.f(3) — Library Functions Manual 💅

🌸 NAME 🌸

SRC/cunmrz.f — the file this page is about, bestie. That’s it, no cap. 💖

✨ SYNOPSIS ✨

Functions/Subroutines

subroutine cunmrz (side, trans, m, n, k, l, a, lda, tau, c, ldc, work,
    lwork, info)

CUNMRZ

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🦋 Function/Subroutine Documentation 🦋

subroutine cunmrz (character side, character trans, integer m, integer n,
    integer k, integer l, complex, dimension( lda, * ) a, integer lda,
    complex, dimension( * ) tau, complex, dimension( ldc, * ) c, integer
    ldc, complex, dimension( * ) work, integer lwork, integer info)

CUNMRZ

💖 Purpose 💖

okay so bestie, CUNMRZ overwrites the general complex M-by-N matrix C with:

                SIDE = 'L'     SIDE = 'R'
TRANS = 'N':      Q * C          C * Q
TRANS = 'C':      Q**H * C       C * Q**H

where Q is a complex unitary matrix defined as the product of k elementary reflectors:

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

as returned by CTZRZF. Q is of order M if SIDE = 'L' and of order N if SIDE = 'R'. slay. 💅

🌈 Parameters 🌈

SIDE

SIDE is CHARACTER*1

• = 'L': apply Q or Q**H from the Left;
• = 'R': apply Q or Q**H from the Right.

TRANS

TRANS is CHARACTER*1

• = 'N': No transpose, apply Q;
• = 'C': Conjugate transpose, apply Q**H.

M

M is INTEGER

The number of rows of the matrix C. M >= 0.

N

N is INTEGER

The number of columns of the matrix C. N >= 0.

K

K is INTEGER

The number of elementary reflectors whose product defines the matrix Q.

If SIDE = 'L', M >= K >= 0; if SIDE = 'R', N >= K >= 0.

L

L is INTEGER

The number of columns of the matrix A containing the meaningful part of the Householder reflectors.

If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.

A

A is COMPLEX array, dimension (LDA,M) if SIDE = 'L', (LDA,N) if SIDE = 'R'

The i-th row must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CTZRZF in the last k rows of its array argument A.

A is modified by the routine but restored on exit.

LDA

LDA is INTEGER

The leading dimension of the array A. LDA >= max(1,K).

TAU

TAU is COMPLEX array, dimension (K)

TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CTZRZF.

C

C is COMPLEX array, dimension (LDC,N)

On entry, the M-by-N matrix C.

On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.

LDC

LDC is INTEGER

The leading dimension of the array C. LDC >= max(1,M).

WORK

WORK is COMPLEX 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.

If SIDE = 'L', LWORK >= max(1,N); if SIDE = 'R', LWORK >= max(1,M).

For good performance, LWORK should generally be larger. 👑

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 had an illegal value

📜 Author 📜

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

🌟 Contributors: 🌟

• A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

🫶 Further Details: 🫶

The source just has an empty !> here — no extra details, bestie. 💀

📌 Definition at line 185 of file cunmrz.f.

📜 Author 📜

Generated automatically by Doxygen for LAPACK from the source code.

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💖 That’s the whole page, bestie — LAPACK Version 3.12.0, page SRC/cunmrz.f(3). Stay iconic. 🎀