DORGQR(3)

DORGQR(3) 💅✨

Okay bestie, welcome to the LAPACK corner of the Library Functions Manual — this page is for dorgqr.f(3), and the file itself lives at /home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/dorgqr.f. We're generating an orthonormal Q, and it's giving main-character energy, no cap.

NAME 💖

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

That's literally the whole NAME section, bestie — the path is the name.

SYNOPSIS 🦋

Functions/Subroutines 🌸

• subroutine DORGQR (m, n, k, a, lda, tau, work, lwork, info) — the subroutine, and the label under it is just DORGQR.

subroutine DORGQR (m, n, k, a, lda, tau, work, lwork, info)
           DORGQR

Function/Subroutine Documentation 🎀

subroutine DORGQR (...) 👑

subroutine DORGQR (integer m, integer n, integer k, double precision,
    dimension( lda, * ) a, integer lda, double precision, dimension( * )
    tau, double precision, dimension( * ) work, integer lwork, integer info)

Label: DORGQR.

Purpose ✨

DORGQR generates an M-by-N real matrix Q with orthonormal columns, and Q is defined as the first N columns of a product of K elementary reflectors of order M:

Q  =  H(1) H(2) . . . H(k)

as returned by DGEQRF.

Parameters 🧚

• M — M is INTEGER, and it's the number of rows of the matrix Q. Constraint: M >= 0.
• N — N is INTEGER, and it's the number of columns of the matrix Q. Constraint: M >= N >= 0.
• K — K is INTEGER, and it's the number of elementary reflectors whose product defines the matrix Q. Constraint: N >= K >= 0.
• A — A is a DOUBLE PRECISION array, dimension (LDA,N). On entry, the i-th column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by DGEQRF in the first k columns of its array argument A. On exit, it holds the M-by-N matrix Q. Iconic behavior, honestly.
• LDA — LDA is INTEGER, and it's the first dimension of the array A. Constraint: LDA >= max(1,M).
• TAU — TAU is a DOUBLE PRECISION array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by DGEQRF.
• WORK — WORK is a DOUBLE PRECISION array, dimension (MAX(1,LWORK)). On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
• LWORK — LWORK is INTEGER, and it's the dimension of the array WORK. Constraint: LWORK >= max(1,N). For optimum performance, LWORK >= N*NB, where NB is the optimal blocksize.

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. If INFO = 0, it's a successful exit. If INFO < 0, then if INFO = -i, the i-th argument has an illegal value.

Author 🌈

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

Definition at line 127 of file dorgqr.f. ⭐

Author 🫶

Generated automatically by Doxygen for LAPACK from the source code.

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Bye bestie 💜 — the footer says LAPACK, Version 3.12.0, and /home/abui...RC/dorgqr.f(3). There's no date listed in the footer, so I'm not gonna invent one, periodt.