Re: [Gretl-devel] slight qform() generalization

Let me just add a footnote to this discussion. My claim, infra, is more or less, "Don't try to second-guess gretl in respect of matrix operations, just write the 'natural' code (e.g. "X'X" for X'X) and chances are you'll get optimal performance." I'm reasonably confident about this in general, but there may well be some counter-examples. If you find one, please let us know and we'll try to fix it. As shown by Jack's timing comparison script (also infra) there's no need to speculate about whether hansl code variant A is or is not faster than hansl code variant B. Just wrap the calculation in a big fat loop and apply $stopwatch to both versions -- the empirical method. Allin