/home/abui...D/dgeqrs.f(3)

📦 version 3.12.0, in opensuse-leap 16.0

🌸 dgeqrs.f(3) — Library Functions Manual 🌸

okay so bestie, welcome to the Library Functions Manual page for /home/abui...D/dgeqrs.f(3). It's giving LAPACK, it's giving QR least-squares, and yes, the source path literally has DEPRECATED in it. No gatekeeping here — let's unpack the whole thing. 💅✨

📛 NAME 📛

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

That's the name section, bestie. It's just the full path, and we respect it. 🫶

🛠️ SYNOPSIS 🛠️

Functions/Subroutines

  • subroutine DGEQRS (m, n, nrhs, a, lda, tau, b, ldb, work, lwork, info) — aka DGEQRS. That's the whole little synopsis moment.

🧮 Function/Subroutine Documentation 🧮

subroutine DGEQRS

subroutine DGEQRS (integer m, integer n, integer nrhs, double precision,
     dimension( lda, * ) a, integer lda, double precision, dimension( * )
     tau, double precision, dimension( ldb, * ) b, integer ldb, double
     precision, dimension( lwork ) work, integer lwork, integer info)
     DGEQRS

🎯 Purpose

Solve the least squares problem

min || A*X - B ||

using the QR factorization

A = Q*R

computed by DGEQRF. periodt. 🔥

🌈 Parameters 🌈

M

M is INTEGER. It's the number of rows of the matrix A, and the rule is M >= 0. slay. ✨

N

N is INTEGER. It's the number of columns of the matrix A, with M >= N >= 0. iconic constraints only. 💖

NRHS

NRHS is INTEGER. It's the number of columns of B, and NRHS >= 0. no cap. 🦋

A

A is a DOUBLE PRECISION array, dimension (LDA,N). It holds the details of the QR factorization of the original matrix A as returned by DGEQRF. literally the QR tea. 🎀

LDA

LDA is INTEGER. It's the leading dimension of the array A, and you need LDA >= M. respect the leading dimension, bestie. 💅

TAU

TAU is a DOUBLE PRECISION array, dimension (N). It holds the details of the orthogonal matrix Q. the Q details are in there, iykyk. 🌸

B

B is a DOUBLE PRECISION array, dimension (LDB,NRHS).

On entry, it's the m-by-nrhs right hand side matrix B. On exit, it's the n-by-nrhs solution matrix X. so it really said "I'm both." main character energy fr fr. 👑

LDB

LDB is INTEGER. It's the leading dimension of the array B, and LDB >= M. yes, another leading dimension check. we love consistency. ⭐

WORK

WORK is a DOUBLE PRECISION array, dimension (LWORK). it's the workspace, doing workspace things. 🧚

LWORK

LWORK is INTEGER. It's the length of the array WORK.

LWORK must be at least NRHS, and should be at least NRHS*NB, where NB is the block size for this environment. highkey important sizing info. 🔥

INFO

INFO is INTEGER.

  • = 0: successful exit — we love a win. 🎉
  • < 0: if INFO = -i, the i-th argument had an illegal value — not the vibe. 💀

👑 Author

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

Definition at line 119 of file dgeqrs.f.

✨ Author ✨

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