John Darrington <[EMAIL PROTECTED]> writes: > I've started looking at the NPAR TEST command. It has a lot of > subcommands, most of which are unrelated (IMHO they should all be > seperate commands), so I'll probably implement them one at a time > and check them in as and when they're complete.
Makes sense. > 1. I'm intending to put in more effort (compared to other > commands I've implemented) to seperate the parsing of the command > from its execution. My idea is that the parser should produce > some kind of abstract base class, implementations of which can then > be executed by the "backend". I'm hopefull that this idea, if > successful, could then be extended for all commands. Yes, this is clearly how we should build things. It just hasn't usually worked out that way ;-( > 2. In the NPAR command, spss has /SAMPLE and /METHOD subcommands, > which, if used, make the command do monte-carlo sampling of the > dataset rather than iteration. So far as I can tell, this is a > hack, to avoid memory exhaustion. PSPP's casefiles should entirely > avoid this problem (unless disk space is also exhausted), so I'm > proposing that PSPP just accepts and ignores these subcommands > ... unless anyone can give me a good reason to do otherwise. I know that sometimes people try comparing the results obtained with different random samples to determine some kind of "reliability" measure for models. I don't, however, know if this makes sense for these kinds of statistics or whether these subcommands could be used for that purpose. > 3. I've been thinking about various optimisations which NPAR can > make. One significant optimisation can only be used if > multiple tests are asked for and if /MISSING LISTWISE INCLUDE is > specified, which can avoid extra sorting. However, my guess > is that few if any users will use that particular combination, so > I'm thinking that this optimisation is probably not worth the > effort. Comments? In my opinion, don't waste time optimizing rare cases. > 4. Many of the output tables make a lot of use of subscripted > footnotes. I wonder how much effort it would take to implement > such a feature, as a stop-gap measure until we get a new output > subsystem? Not too hard, I think. I'll put it on my to-do list. > 5. I'm becoming aware, that different developers, and indeed the > same developers at different times, are making inconsistent use of > style in output tables, with regards to eg: text alignment, double > vs. single lines, bold fonts, output precision etc. Perhaps we > need a "manual of style" to make some recommendations here. Definitely. -- God leaned close as mud as man sat up, looked around, and spoke. Man blinked. "What is the purpose of all this?" he asked politely. "Everything must have a purpose?" asked God. "Certainly," said man. "Then I leave it to you to think of one for all this," said God. And He went away. --Vonnegut, _Cat's Cradle_ _______________________________________________ pspp-dev mailing list [email protected] http://lists.gnu.org/mailman/listinfo/pspp-dev
