ZUNG2R(3)

💅 ZUNG2R(3) 💅

okay bestie, this page is from the Library Functions Manual, and the title is literally ZUNG2R(3) — one iconic subroutine, zero filler. it's giving “just read the signature and slay.” 🫶

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🌸 NAME 🌸

the NAME section is not even a name, it’s just the source path, and we are keeping it exactly:

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/zung2r.f

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✨ SYNOPSIS ✨

🎀 Functions/Subroutines 🎀

subroutine ZUNG2R (m, n, k, a, lda, tau, work, info)
    ZUNG2R

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💖 Function/Subroutine Documentation 💖

the full signature is right here, bestie — every type, every dimension, every comma:

subroutine ZUNG2R (integer m, integer n, integer k, complex*16, dimension(
       lda, * ) a, integer lda, complex*16, dimension( * ) tau, complex*16,
       dimension( * ) work, integer info)

and yes, the doc title says ZUNG2R again. branding. 👑

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🦋 Purpose 🦋

okay so ZUNG2R generates an m by n complex matrix Q with orthonormal columns. it’s 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 ZGEQRF. periodt. 💅

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🫶 Parameters 🫶

• M — INTEGER. the number of rows of the matrix Q. constraint: M >= 0.
• N — INTEGER. the number of columns of the matrix Q. constraint: M >= N >= 0.
• K — INTEGER. the number of elementary reflectors whose product defines the matrix Q. constraint: N >= K >= 0.
• A — COMPLEX*16 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 ZGEQRF in the first k columns of its array argument A. on exit, the m by n matrix Q.
• LDA — INTEGER. the first dimension of the array A. constraint: LDA >= max(1,M).
• TAU — COMPLEX*16 array, dimension (K). TAU(i) must contain the scalar factor of the elementary reflector H(i), as returned by ZGEQRF.
• WORK — COMPLEX*16 array, dimension (N).
• INFO — INTEGER. = 0: successful exit. < 0: if INFO = -i, the i-th argument has an illegal value.

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👑 Author 👑

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

Definition at line 113 of file zung2r.f.

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🌈 Author 🌈

and yeah, the page says: Generated automatically by Doxygen for LAPACK from the source code.

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okay bestie, that’s the whole page. the footer says LAPACK Version 3.12.0 and points at /home/abui...RC/zung2r.f(3) — no separate date line shown, so that’s the full tea. stay slay, and may your reflectors always be elementary. 💖✨🎀