SRC/cunml2.f(3)

✨ CUNML2 — SRC/cunml2.f ✨

okay so this page is from the Library Functions Manual, and it's all about SRC/cunml2.f(3) — the unblocked LQ glow-up routine. Buckle up, bestie. 💅

🎀 NAME 🎀

SRC/cunml2.f

That's the file, periodt. 🫶

🦋 SYNOPSIS 🦋

🧚 Functions/Subroutines 🧚

subroutine cunml2 (side, trans, m, n, k, a, lda, tau, c, ldc, work,
    info)

CUNML2 multiplies a general matrix by the unitary matrix from the LQ factorization determined by cgelqf (unblocked algorithm). ate. ✨

💅 Function/Subroutine Documentation 💅

subroutine cunml2 (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 info)

CUNML2 multiplies a general matrix by the unitary matrix from the LQ factorization determined by cgelqf (unblocked algorithm). No cap. 🦋

🌸 Purpose 🌸

CUNML2 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(k)**H . . . H(2)**H H(1)**H

as returned by CGELQF. Q is of order m if SIDE = 'L' and of order n if SIDE = 'R'. iykyk 💖

🎀 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': apply Q (No transpose)
• = 'C': apply Q**H (Conjugate transpose)

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,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 CGELQF in the first k rows of its array argument A.

heads up, bestie: 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 CGELQF. 🎀

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

👑 Author 👑

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

Definition at line 157 of file cunml2.f.

🌟 Author 🌟

Generated automatically by Doxygen for LAPACK from the source code.

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💖 cute sign-off, bestie: LAPACK Version 3.12.0, page SRC/cunml2.f(3) — mwah, periodt. 💖