SRC/cunmql.f(3)

📦
version 3.12.1 · 7 versions
, in arch rolling

💅 SRC/cunmql.f(3)

okay so bestie, this page is from the Library Functions Manual and it's literally all about SRC/cunmql.f — LAPACK subroutine energy, no cap. ✨

💖 NAME

SRC/cunmql.f

✨ SYNOPSIS

🎀 Functions/Subroutines

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

🦋 Function/Subroutine Documentation

subroutine cunmql (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)
       CUNMQL

💖 Purpose

okay so here's the tea: CUNMQL 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(k) . . . H(2) H(1)

as returned by CGEQLF. 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 CGEQLF in the last 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 CGEQLF.

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 cunmql.f.

🌈 Author

Generated automatically by Doxygen for LAPACK from the source code.

💖 cute sign-off: this page is from LAPACK Version 3.12.0, and the footer page is SRC/cunmql.f(3) — no date line was printed, bestie, so I'm not inventing one. Mwah 💅✨

📦 where this page comes from