TESTING/LIN/dgerqs.f(3)

📦
version 3.12.1 · 2 versions
, in arch rolling

💅 NAME

okay bestie, this is TESTING/LIN/dgerqs.f(3) from the Library Functions Manual — the LAPACK testing-page drop for dgerqs, aka DGERQS. It’s giving “I know her” energy, no cap. ✨

🎀 SYNOPSIS

🧚 Functions/Subroutines

  • subroutine dgerqs (m, n, nrhs, a, lda, tau, b, ldb, work, lwork, info) — DGERQS

💖 Function/Subroutine Documentation

subroutine dgerqs (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)

DGERQS

🎯 Purpose

Bestie, this routine computes a minimum-norm solution:

min || A*X - B ||

using the RQ factorization:

A = R*Q

computed by DGERQF. That’s the whole vibe. 💫

🦋 Parameters

  • M — M is INTEGER. The number of rows of the matrix A. M >= 0.
  • N — N is INTEGER. The number of columns of the matrix A. N >= M >= 0.
  • NRHS — NRHS is INTEGER. The number of columns of B. NRHS >= 0.
  • A — A is DOUBLE PRECISION array, dimension (LDA,N). Details of the RQ factorization of the original matrix A as returned by DGERQF.
  • LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= M.
  • TAU — TAU is DOUBLE PRECISION array, dimension (M). Details of the orthogonal matrix Q.
  • B — B is DOUBLE PRECISION array, dimension (LDB,NRHS). On entry, the right hand side vectors for the linear system. On exit, the solution vectors X. Each solution vector is contained in rows 1:N of a column of B.
  • LDB — LDB is INTEGER. The leading dimension of the array B. LDB >= max(1,N).
  • WORK — WORK is DOUBLE PRECISION array, dimension (LWORK).
  • LWORK — LWORK is INTEGER. 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.
  • INFO — INFO is INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument had an illegal value. periodt, that’s the error tea. 🚨

👑 Author

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

Definition at line 120 of file dgerqs.f.

🌸 Author

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and that’s the whole dgerqs page, bestie 🫶 this one came from LAPACK Version 3.12.0 and lives at TESTING/LIN/dgerqs.f(3) — iconic footer behavior, fr fr. 💖

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