On Wed, Aug 12, 2009 at 5:04 PM, Jason Grout<jason-s...@creativetrax.com> wrote: > > William Stein wrote: >> On Tue, Aug 11, 2009 at 11:30 PM, Jason >> Grout<jason-s...@creativetrax.com> wrote: >>> William Stein wrote: >>>> Hi, >>>> >>>> I just wanted to let people know that David Ackerman -- a UW student who >>>> took my course on Sage last quarter -- is working (funded by NSF) on >>>> creating a "units package" for Sage right _now_. If anybody has any >>>> pseudo-sage code that involves units that they wished work, please post >>>> it to this thread. What do you want units to *do*? >>>> >>> Is he doing something from scratch or is he working from the packages >>> that have come up from time to time here? >> >> He is doing something from scratch. >> >> I had planned to have him work on integrating some existing package, >> but after evaluating that approach he said it didn't seem to make >> sense (at least he has a lot of experience using Sage, since he took >> my class). I didn't have an opinion one way or the other, but we >> decided to ask -- "what is a so called units package supposed to do >> anyways" since I honestly couldn't really tell you. I would use one >> to convert between Fahrenheit and Celcius, and maybe dollars and euros >> :-). We google around and found that Matlab didn't seem to come with >> a units package, but there were several third party packages -- anyway >> Sage isn't much like Matlab so looking there seemed pointless. Then >> we looked at Mathematica's included units package and read all the >> documentation and examples of it. That was enlightening, and >> suggested doing almost precisely what Robert Dodier keeps telling us >> to do, which is make the different units just be symbolic variables, >> plus have some extra table somewhere of conversions (where everything >> is kept as exact fractions), and add a few functions to do >> conversions. If you read the Mathematica docs you'll see that *all* >> their units package is is: >> >> * a function Convert to convert between units >> >> * a very big list of different standard units (e.g., Foot, >> Mile, Meter Second, etc.), which are all literally just symbolic >> variables. >> >> * ConvertTemperature (and 3 other convert style functions). >> >> That's it. > > > I would also hope that there is a way to define my own units in terms of > standard units, or even my own system. For example, 100 pages is a > book, 10 books is a shelf, 14 shelves is a bookcase, etc.
And the following would be good for a laugh :-) 2 monograms = 1 diagram 8 nickles = 2 paradigms 2 wharves = 1 paradox 10E5 bicycles = 2 megacycles 1 unit of suspense in an Agatha Christie novel = 1 whod unit Reference: http://cnonline.net/~TheCookieJar/math_jokes_01.html Or maybe these :-) 1 million microphones = 1 megaphone 1 million bicycles = 2 megacycles 2000 mockingbirds = 2 kilomocking 10 cards = 1 decacards 1/2 lavatory = 1 demijohn 1 millonth of a fish- 1 microfiche 453.6 graham crackers = 1 pound cake 10 rations = 1 decoration 10 millipedes = 1 centipede 3-1/3 tridents = 1 decadent 10 monologues = 5 dialogues Reference: http://www.doe.virginia.gov/Div/Winchester/jhhs/math/humor/metric.html -- Regards Minh Van Nguyen --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
