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SRC/sorg2r.f(3) LAPACK SRC/sorg2r.f(3)

SRC/sorg2r.f


subroutine sorg2r (m, n, k, a, lda, tau, work, info)
SORG2R generates all or part of the orthogonal matrix Q from a QR factorization determined by sgeqrf (unblocked algorithm).

SORG2R generates all or part of the orthogonal matrix Q from a QR factorization determined by sgeqrf (unblocked algorithm).

Purpose:


SORG2R generates an m by n real 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 SGEQRF.

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 REAL 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 SGEQRF 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 REAL array, dimension (K)
TAU(i) must contain the scalar factor of the elementary
reflector H(i), as returned by SGEQRF.

WORK


WORK is REAL array, dimension (N)

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 113 of file sorg2r.f.

Generated automatically by Doxygen for LAPACK from the source code.

Sun Jan 12 2025 15:13:31 Version 3.12.1

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