SRC/cunmqr.f(3)

💅 SRC/cunmqr.f(3) 💅

from the Library Functions Manual, bestie — this is the LAPACK page, and we are keeping every fact while making it cute.

🎀 NAME 🎀

SRC/cunmqr.f

✨ SYNOPSIS ✨

Functions/Subroutines

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

🦋 Function/Subroutine Documentation 🦋

🌸 cunmqr — the main character 🌸

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

CUNMQR

💖 Purpose 💖

Okay so CUNMQR 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 CGEQRF. Q is of order M if SIDE = 'L' and of order N if SIDE = 'R'.

🌈 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.
• A — A is COMPLEX array, dimension (LDA,K); the i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CGEQRF in the first k columns of its array argument A.
• LDA — LDA is INTEGER; the leading dimension of the array A. If SIDE = 'L', LDA >= max(1,M); if SIDE = 'R', LDA >= max(1,N).
• TAU — TAU is COMPLEX array, dimension (K); TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGEQRF.
• 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.

Definition at line 166 of file cunmqr.f.

💖 Author 💖

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie — no cap. This one is SRC/cunmqr.f(3) from LAPACK Version 3.12.0. Now go forth and apply your Q and Q**H with main character energy. 💅✨🦋