CLAQP2(3)

NAME 🦋

/home/abuild/rpmbuild/BUILD/lapack-static-3.12.0-build/lapack-3.12.0/SRC/claqp2.f — that’s the file path this page is about, bestie. Also, hi, this is CLAQP2(3) and it lives under the Library Functions Manual ✨

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SYNOPSIS 🎀

Functions/Subroutines 💖

• subroutine CLAQP2 (m, n, offset, a, lda, jpvt, tau, vn1, vn2, work) — CLAQP2 computes a QR factorization with column pivoting of the matrix block.

subroutine CLAQP2 (integer m, integer n, integer offset, complex, dimension(
       lda, * ) a, integer lda, integer, dimension( * ) jpvt, complex,
       dimension( * ) tau, real, dimension( * ) vn1, real, dimension( * ) vn2,
       complex, dimension( * ) work)

Function/Subroutine Documentation 💅

Purpose 🌸

Okay so CLAQP2 computes a QR factorization with column pivoting of the block A(OFFSET+1:M,1:N). The block A(1:OFFSET,1:N) is accordingly pivoted, but it is not factorized. Periodt. 🫶

Parameters 🧚

• M — M is INTEGER. It’s the number of rows of the matrix A. M >= 0.
• N — N is INTEGER. It’s the number of columns of the matrix A. N >= 0.
• OFFSET — OFFSET is INTEGER. The number of rows of the matrix A that must be pivoted but not factorized. OFFSET >= 0.
• A — A is COMPLEX array, dimension (LDA,N). On entry, the M-by-N matrix A. On exit, the upper triangle of block A(OFFSET+1:M,1:N) is the triangular factor obtained; the elements in block A(OFFSET+1:M,1:N) below the diagonal, together with the array TAU, represent the orthogonal matrix Q as a product of elementary reflectors. Block A(1:OFFSET,1:N) has been accordingly pivoted, but not factorized. 👑
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,M).
• JPVT — JPVT is INTEGER array, dimension (N). On entry, if JPVT(i) .ne. 0, the i-th column of A is permuted to the front of A*P (a leading column); if JPVT(i) = 0, the i-th column of A is a free column. On exit, if JPVT(i) = k, then the i-th column of A*P was the k-th column of A.
• TAU — TAU is COMPLEX array, dimension (min(M,N)). The scalar factors of the elementary reflectors.
• VN1 — VN1 is REAL array, dimension (N). The vector with the partial column norms.
• VN2 — VN2 is REAL array, dimension (N). The vector with the exact column norms.
• WORK — WORK is COMPLEX array, dimension (N).

Author 💖

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

Contributors: 🌸

• G. Quintana-Orti, Depto. de Informatica, Universidad Jaime I, Spain
• X. Sun, Computer Science Dept., Duke University, USA
• Partial column norm updating strategy modified on April 2011 Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb, Croatia.

References: 🔥

• LAPACK Working Note 176

Definition at line 147 of file claqp2.f. 📍

Author 🌈

Generated automatically by Doxygen for LAPACK from the source code.

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That’s the whole page, bestie! Final footer vibes: source/version is LAPACK, Version 3.12.0, and the path is /home/abui...RC/claqp2.f(3) — no date on this footer, just pure manpage energy 💖✨