function subpak_test059 ( ) %*****************************************************************************80 % %% TEST059 tests R8MAT_HOUSE_FORM and R8VEC_HOUSE_COLUMN. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 19 April 2009 % % Author: % % John Burkardt % n = 4; b = 0.0; c = 5.0; fprintf ( 1, '\n' ); fprintf ( 1, 'TEST059\n' ); fprintf ( 1, ' R8VEC_HOUSE_COLUMN returns the compact form of\n' ); fprintf ( 1, ' a Householder matrix that "packs" a column\n' ); fprintf ( 1, ' of a matrix.\n' ); % % Get a random matrix. % seed = 123456789; [ a, seed ] = r8mat_uniform_ab ( n, n, b, c, seed ); r8mat_print ( n, n, a, ' Matrix A:' ); for k = 1 : n-1 fprintf ( 1, '\n' ); fprintf ( 1, ' Working on column K = %d\n', k ); v = r8vec_house_column ( n, a(1:n,k), k ); h = r8mat_house_form ( n, v ); r8mat_print ( n, n, h, ' Householder matrix H:' ); ha = h * a; r8mat_print ( n, n, ha, ' Product H*A:' ); % % If we set A := HA, then we can successively convert A to upper % triangular form. % a = ha; end return end