From: Jan R. <ja...@ry...> - 2005-12-06 16:41:10
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>>>>> "Raymond" == Raymond Toy <ray...@er...>: >>>>> "Jan" == Jan Rychter <ja...@ry...> writes: Jan> I started using matlisp very recently and the things that were Jan> missing were: Jan> -- why wasn't pinv (pseudoinverse) incorporated? I had to put it Jan> in myself, and the patches were posted to the list some months ago... Raymond> Mostly because no one wanted it early on, and later because I Raymond> was lazy. Fair enough! Raymond> It also doesn't help my motivation when someone (not you!) Raymond> asks for some functionality, and I ask a question about it, Raymond> and never hear from him again. Well, we'll try to be better this time :-) Jan> -- not enough efficient data manipulation tools: the macros I Jan> posted for operating on rows and columns are an example. I Jan> really really need those to do anything serious. Raymond> What other kind of data manipulation tools are you looking Raymond> for? Basically, something corresponding to my extract-row and extract-column macros. An important point in my case is that I'd like to have extra-efficient versions of those for some operations. Ideally I'd like to be able to do an (m- (extract-column m i) b) without actually copying the elements of that column. Jan> -- minor stuff, like min/max. Raymond> This kind of stuff isn't there mostly because of my laziness, Raymond> and because of the lack of requests for such functionality. Raymond> Plus, what is min/max supposed to do on a matrix? Return the Raymond> min/max element of the matrix? I use these mostly on vectors, on matrices I'd like to have a row-major and a column-major min/max, each returning a vector. Perhaps a min/max on the entire matrix is useful for people as well, I don't know. --J. |