I have a large real symmetric square matrix (with millions of rows/columns). How can I identify the sets of rows that are linearly dependent? More generally, can I determine linear independence of rows with a continuous function where, say, the function is 1.0 for a row that is linearly independent and 0.0 when it is linearly dependent. I am interested in identifying rows that are almost linearly dependent. For example, say that due to round-off error rows A and B are identical in all columns except that they differ by 1 part per million in one column's entries.