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sorg2l.f(3) LAPACK sorg2l.f(3)

NAME

sorg2l.f -

SYNOPSIS

Functions/Subroutines


subroutine sorg2l (M, N, K, A, LDA, TAU, WORK, INFO)
 
SORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).

Function/Subroutine Documentation

subroutine sorg2l (integerM, integerN, integerK, real, dimension( lda, * )A, integerLDA, real, dimension( * )TAU, real, dimension( * )WORK, integerINFO)

SORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).
Purpose: 
 SORG2L generates an m by n real matrix Q with orthonormal columns,
 which is defined as the last n columns of a product of k elementary
 reflectors of order m


       Q  =  H(k) . . . H(2) H(1)


 as returned by SGEQLF.
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 (n-k+i)-th column must contain the vector which
          defines the elementary reflector H(i), for i = 1,2,...,k, as
          returned by SGEQLF in the last 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 SGEQLF.
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 sorg2l.f.

Author

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