CUNGQR(3)

CUNGQR(3) 💅

okay so bestie, this is the Library Functions Manual page for cungqr.f(3) — the header path is /home/abui...RC/cungqr.f(3) on both sides, no cap. CUNGQR is the main character here and it's lowkey iconic. ✨

💖 NAME

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

🌸 SYNOPSIS

Functions/Subroutines

• subroutine CUNGQR (m, n, k, a, lda, tau, work, lwork, info) — the whole callable vibe. CUNGQR is literally right there in the name. 👑

🦋 Function/Subroutine Documentation

Here's the full typed signature, bestie — copy it exactly, no improv:

   subroutine CUNGQR (integer m, integer n, integer k, complex, dimension( lda,
       * ) a, integer lda, complex, dimension( * ) tau, complex, dimension( * )
       work, integer lwork, integer info)

yep, the name again: CUNGQR. Slay.

Purpose:

CUNGQR generates an M-by-N complex matrix Q with orthonormal columns, which 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 CGEQRF. That's the whole glow-up.

Parameters

• M — M is INTEGER. The number of rows of the matrix Q. M >= 0.
• N — N is INTEGER. The number of columns of the matrix Q. M >= N >= 0.
• K — K is INTEGER. The number of elementary reflectors whose product defines the matrix Q. N >= K >= 0.
• A — A is COMPLEX 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 CGEQRF in the first k columns of its array argument A. On exit, the M-by-N matrix Q.
• LDA — LDA is INTEGER. The first dimension of the array A. LDA >= max(1,M).
• TAU — TAU is COMPLEX array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by CGEQRF.
• 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. 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.
  • = 0: successful exit
  • < 0: 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 cungqr.f.

Definition at line 127 of file cungqr.f. 🎀

👑 Author

Generated automatically by Doxygen for LAPACK from the source code.

---

xoxo, cute sign-off time: LAPACK Version 3.12.0, footer path /home/abui...RC/cungqr.f(3) — and no separate date is printed, periodt. 💖🎀