SRC/cunmr3.f(3)

💅 NAME

SRC/cunmr3.f — that's the name, bestie. This page is from the Library Functions Manual, and it's giving very specific LAPACK energy.

✨ SYNOPSIS

Functions/Subroutines

subroutine cunmr3 (side, trans, m, n, k, l, a, lda, tau, c, ldc, work,
    info)
    CUNMR3 multiplies a general matrix by the unitary matrix from a RZ
    factorization determined by ctzrzf (unblocked algorithm).

🦋 Function/Subroutine Documentation

subroutine cunmr3 (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 info)

CUNMR3 multiplies a general matrix by the unitary matrix from a RZ factorization determined by ctzrzf (unblocked algorithm). Iconic behavior, honestly.

🎀 Purpose

Okay so CUNMR3 overwrites the general complex m by n matrix C with:

Q * C  if SIDE = 'L' and TRANS = 'N', or

Q**H* C  if SIDE = 'L' and TRANS = 'C', or

C * Q  if SIDE = 'R' and TRANS = 'N', or

C * Q**H if SIDE = 'R' and TRANS = 'C',

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. Pick a side, bestie.
• TRANS — TRANS is CHARACTER*1; = 'N': apply Q (No transpose); = 'C': apply Q**H (Conjugate transpose). The C is for conjugate, not for "casual."
• 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 — so it gets touched, but it comes back, no cap.
• 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 (N) if SIDE = 'L', (M) if SIDE = 'R'.
• INFO — INFO is INTEGER; = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value. Rude little error code, but at least it's clear.

👑 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

Literally just !> and then nothing — the section is empty, bestie, no extra lore.

Definition at line 176 of file cunmr3.f.

💖 Author

Generated automatically by Doxygen for LAPACK from the source code.

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okay bye bestie — this whole page is from LAPACK, Version 3.12.0, for SRC/cunmr3.f(3). Periodt. 💅✨