CGEMLQ(3)

💖 NAME 💖

Okay bestie, welcome to CGEMLQ(3) from the Library Functions Manual! This page is literally named after this file path, no cap:

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

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✨ SYNOPSIS ✨

🧚 Functions/Subroutines 🧚

It’s a one-icon show, and she’s serving the full CGEMLQ signature:

subroutine CGEMLQ (side, trans, m, n, k, a, lda, t, tsize, c, ldc, work,
    lwork, info)
    CGEMLQ

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💅 Function/Subroutine Documentation 💅

Here’s the detailed signature, bestie — every type, every dimension, all of it:

subroutine CGEMLQ (character side, character trans, integer m, integer n,
    integer k, complex, dimension( lda, * ) a, integer lda, complex,
    dimension( * ) t, integer tsize, complex, dimension( ldc, * ) c, integer
    ldc, complex, dimension( * ) work, integer lwork, integer info)

The subroutine is CGEMLQ. Periodt. 👑

🎯 Purpose 🎯

Bestie, the whole point is this: CGEMLQ overwrites the general real 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 blocked elementary reflectors computed by short wide LQ factorization (CGELQ).

🎀 Parameters 🎀

• SIDE — SIDE is CHARACTER*1; = 'L': apply Q or Q**H from the Left; = 'R': apply Q or Q**H from the Right. Left or right, she can do both. 💅
• TRANS — TRANS is CHARACTER*1; = 'N': No transpose, apply Q; = 'C': Conjugate transpose, apply Q**H. Transpose drama handled. 🦋
• M — M is INTEGER; The number of rows of the matrix A. 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. Respect the bounds, bestie. ✨
• A — A is COMPLEX array, dimension (LDA,M) if SIDE = 'L', (LDA,N) if SIDE = 'R'; Part of the data structure to represent Q as returned by CGELQ.
• LDA — LDA is INTEGER; The leading dimension of the array A. LDA >= max(1,K).
• T — T is COMPLEX array, dimension (MAX(5,TSIZE)). Part of the data structure to represent Q as returned by CGELQ.
• TSIZE — TSIZE is INTEGER; The dimension of the array T. TSIZE >= 5.
• 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. She comes in as C, leaves as a whole new vibe. 😭🔥
• LDC — LDC is INTEGER; The leading dimension of the array C. LDC >= max(1,M).
• WORK — (workspace) COMPLEX array, dimension (MAX(1,LWORK))
• LWORK — LWORK is INTEGER; The dimension of the array WORK. If LWORK = -1, then a workspace query is assumed. The routine only calculates the size of the WORK array, returns this value as WORK(1), and no error message related to WORK is issued by XERBLA. Workspace query mode: not me asking for my own space. 🫶
• 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.

🔥 Further Details 🔥

These details are particular for this LAPACK implementation. Users should not take them for granted. These details may change in the future, and are not likely true for another LAPACK implementation. These details are relevant if one wants to try to understand the code. They are not part of the interface.

In this version,

• T(2): row block size (MB)
• T(3): column block size (NB)
• T(6:TSIZE): data structure needed for Q, computed by CLASWQR or CGELQT

Depending on the matrix dimensions M and N, and row and column block sizes MB and NB returned by ILAENV, CGELQ will use either CLASWLQ (if the matrix is wide-and-short) or CGELQT to compute the LQ factorization. This version of CGEMLQ will use either CLAMSWLQ or CGEMLQT to multiply matrix Q by another matrix. Further Details in CLAMSWLQ or CGEMLQT.

Definition at line 170 of file cgemlq.f.

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🌈 Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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mwah 💋 — LAPACK Version 3.12.0, from /home/abui...RC/cgemlq.f(3). Stay slay, bestie! 🌈✨