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sorg2r.f(3) LAPACK sorg2r.f(3)

NAME

sorg2r.f -

SYNOPSIS

Functions/Subroutines


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).

Function/Subroutine Documentation

subroutine sorg2r (integerM, integerN, integerK, real, dimension( lda, * )A, integerLDA, real, dimension( * )TAU, real, dimension( * )WORK, integerINFO)

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.
Date:
September 2012
Definition at line 115 of file sorg2r.f.

Author

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