> Yes it is resonable. My only doubts is that as you > noticed there is only one place that currently uses > two argument 'last', so I am not sure how useful > is extending this functionality by adding new 'last'.
This is how I notice this: I read about an algorithm that "scan once to find the nth last element", the solution is to use 2 pointers. I tested and in the List case, it's much slower than elt(a, #a - n). So, the reason to have these functions which operates from backward is to achieve performance by using the scan once algorithm. I don't know for aggregates other than List, if it's actually faster. Other than performance concerns, it's nice to have functions to operate from backwards instead of writing one's own. I was thinking : delete(a, n), when n < minIndex a, delete (minIndex(a) - n)th last element. Removing last few elements is pretty common in statistic, I think. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/fricas-devel. For more options, visit https://groups.google.com/d/optout.
