SORG2R(3)      LAPACK routine of NEC Numeric Library Collection      SORG2R(3)



NAME
       SORG2R

SYNOPSIS
       SUBROUTINE SORG2R (M, N, K, A, LDA, TAU, WORK, INFO)



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.




ARGUMENTS
           M         (input)
                     M is INTEGER
                     The number of rows of the matrix Q. M >= 0.

           N         (input)
                     N is INTEGER
                     The number of columns of the matrix Q. M >= N >= 0.

           K         (input)
                     K is INTEGER
                     The number of elementary reflectors whose product defines the
                     matrix Q. N >= K >= 0.

           A         (input/output)
                     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       (input)
                     LDA is INTEGER
                     The first dimension of the array A. LDA >= max(1,M).

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

           WORK      (output)
                     WORK is REAL array, dimension (N)

           INFO      (output)
                     INFO is INTEGER
                     = 0: successful exit
                     < 0: if INFO = -i, the i-th argument has an illegal value



LAPACK routine                  31 October 2017                      SORG2R(3)