dorg2l.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

dorg2l.f  

SYNOPSIS


 

Functions/Subroutines


subroutine dorg2l (M, N, K, A, LDA, TAU, WORK, INFO)
DORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).  

Function/Subroutine Documentation

 

subroutine dorg2l (integer M, integer N, integer K, double precision, dimension( lda, * ) A, integer LDA, double precision, dimension( * ) TAU, double precision, dimension( * ) WORK, integer INFO)

DORG2L generates all or part of the orthogonal matrix Q from a QL factorization determined by sgeqlf (unblocked algorithm).

Purpose:

 DORG2L 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 DGEQLF.


 

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


WORK

          WORK is DOUBLE PRECISION 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:

December 2016

Definition at line 116 of file dorg2l.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
Function/Subroutine Documentation
subroutine dorg2l (integer M, integer N, integer K, double precision, dimension( lda, * ) A, integer LDA, double precision, dimension( * ) TAU, double precision, dimension( * ) WORK, integer INFO)
Author
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