.Modelica_LinearSystems2.Math.Matrices.LAPACK.dorgqr

Information

Lapack documentation:

   Purpose
   =======

   DORGQR 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 DGEQRF.

   Arguments
   =========

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

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

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

   A       (input/output) DOUBLE PRECISION 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 DGEQRF in the first k columns of its array
           argument A.
           On exit, the M-by-N matrix Q.

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

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

   WORK    (workspace/output) DOUBLE PRECISION array, dimension (LWORK)
           On exit, if INFO = 0, WORK(1) returns the optimal LWORK.

   LWORK   (input) INTEGER
           The dimension of the array WORK. LWORK >= max(1,N).
           For optimum performance LWORK >= N*NB, where NB is the
           optimal blocksize.

           If LWORK = -1, then a workspace query is assumed; the routine
           only calculates the optimal size of the WORK array, returns
           this value as the first entry of the WORK array, and no error
           message related to LWORK is issued by XERBLA.

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

   =====================================================================

Interface

function dorgqr
  input Real Q[:, :] "Orthogonal matrix of elementary reflectors";
  input Real tau[:] "Scalar factors of the elementary reflectors";
  output Real Qout[size(Q, 1), size(Q, 2)] = Q;
  output Integer info;
end dorgqr;