/home/abui.../cgeqrt2.f(3)

💖 NAME 💖

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/cgeqrt2.f

okay so this is the cgeqrt2.f(3) page from the Library Functions Manual (/home/abui.../cgeqrt2.f(3)), and the main character is CGEQRT2 — a LAPACK subroutine that is lowkey carrying the QR-factorization plot. 🫶

✨ SYNOPSIS ✨

🦋 Functions/Subroutines 🦋

• subroutine CGEQRT2 (m, n, a, lda, t, ldt, info) — the tl;dr is literally: CGEQRT2 computes a QR factorization of a general real or complex matrix using the compact WY representation of Q. 💅

🧚 Function/Subroutine Documentation 🧚

subroutine CGEQRT2 (integer m, integer n, complex, dimension( lda, * ) a, integer lda, complex, dimension( ldt, * ) t, integer ldt, integer info)

bestie, same sentence as above, no cap: CGEQRT2 computes a QR factorization of a general real or complex matrix using the compact WY representation of Q. ✨

🎀 Purpose 🎀

the source is like, and I quote: CGEQRT2 computes a QR factorization of a complex M-by-N matrix A, using the compact WY representation of Q. slay. 💜

🌸 Parameters 🌸

• M — M is INTEGER; it's the number of rows of the matrix A. Constraint: M >= N. 🍓
• N — N is INTEGER; it's the number of columns of the matrix A. Constraint: N >= 0. 🍓
• A — A is COMPLEX array, dimension (LDA,N). On entry, it's the complex M-by-N matrix A. On exit, the elements on and above the diagonal contain the N-by-N upper triangular matrix R; the elements below the diagonal are the columns of V. See below for further details. 👀
• LDA — LDA is INTEGER. It's the leading dimension of the array A. Constraint: LDA >= max(1,M). ✅
• T — T is COMPLEX array, dimension (LDT,N). It's the N-by-N upper triangular factor of the block reflector. The elements on and above the diagonal contain the block reflector T; the elements below the diagonal are not used. See below for further details. 🌀
• LDT — LDT is INTEGER. It's the leading dimension of the array T. Constraint: LDT >= max(1,N). ✅
• INFO — INFO is INTEGER. Exit-status tea: = 0: successful exit; < 0: if INFO = -i, the i-th argument had an illegal value. 🚨

👑 Author 👑

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

🌈 Further Details 🌈

The matrix V stores the elementary reflectors H(i) in the i-th column below the diagonal. For example, if M=5 and N=3, the matrix V is

V = (  1       )
    ( v1  1    )
    ( v1 v2  1 )
    ( v1 v2 v3 )
    ( v1 v2 v3 )

where the vi's represent the vectors which define H(i), which are returned in the matrix A. The 1's along the diagonal of V are not stored in A. The block reflector H is then given by

H = I - V * T * V**H

where V**H is the conjugate transpose of V. 🦋

Definition at line 126 of file cgeqrt2.f.

👑 Author 👑

Generated automatically by Doxygen for LAPACK from the source code. 💖

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okay bye bestie 👋 this page is from LAPACK Version 3.12.0 and lives at /home/abui.../cgeqrt2.f(3) — mwah, stay slaying ✨👑💅