k</mi></math>&#xa0;by <math><mi>k</mi></math>&#xa0;part of <math><mi>R</mi></math>&#xa0;is computed, where <math><mi>k</mi></math>&#xa0;is the estimated rank of <math><mi>A</mi></math>. A tolerance of <math><mn>0.01</mn></math>&#xa0;is used to estimate the rank of <math><mi>A</mi></math>&#xa0;from the upper triangular factor, <math><mi>R</mi></math>.</div><div class="paramtext">Note that the block size (NB) of <math><mn>64</mn></math>&#xa0;assumed in this example is not realistic for such a small problem, b