On Sun, Jul 20, 2008 at 2:44 AM, Jason Grout <[EMAIL PROTECTED]> wrote: > > David Joyner wrote: >> On Sat, Jul 19, 2008 at 6:10 PM, q10 <[EMAIL PROTECTED]> wrote: >>> Hello: >>> >>> It has come to my attention that SAGE does not have a units-conversion >>> program component (maybe it has; if it does, please show me). I >>> recommend adding the GPLed unit conversion program called ConvertAll >>> (http://www.convertall.bellz.org/) I believe it is written with >>> Python, so integration of it into SAGE should not be too difficult. >> >> From the above webpage: >> >> "ConvertAll is free software; you can redistribute it and/or modify it >> under the terms of the GNU General Public License as published by the >> Free Software Foundation; either Version 2 of the License, or (at your >> option) any later version. >> >> ... >> >> ConvertAll requires the following libraries: >> >> * Qt (Version 4.1 or higher - see Trolltech for more information) >> * Python (Version 2.3 or higher) >> * PyQt (Version 4.0 or higher - see Riverbank for more information)" >> >> Requiring Qt might be a problem. However, I don't see why a units-conversion >> package requires a graphics library like Qt. Indeed, the web site says >> >> "Command line options are available to do conversions without the GUI." >> > > > Enthought also has a units python module, which might be interesting to > look at. It's not very well documented, though.
>From the ConvertAll webpage: "Why write another unit converter? There are plenty of them out there. Well, I couldn't find one that worked quite the way I wanted. With ConvertAll, you can combine the units any way you want. If you want to convert from inches per decade, that's fine. Or from meter-pounds. Or from cubic nautical miles. The units don't have to make sense to anyone else." The justification for ConvertAll would be exactly the justification for us to *not* use it in Sage, i.e., for Sage unit conversion we would surely want something that works well in the context of sage itself, e.g., the coercion model, symbolic calculus, etc. Whatever unit conversion sage eventually gets, it will have to be done probably as a bunch of new code that might use something like ConvertAll or enthought's unit code to do some of the real work behind the scenes. I think something like this will happen when a student comes to me (or whoever) asking for a several-months long Sage development project, and unit conversion is something they find interesting. It's the sort of thing where one would have to: (a) research exactly what Maple, Mathematica, and Matlab do (b) come up with a SEP inspired by (a) for Sage, and get it discussed on sage-devel, (c) survey the range of existing unit conversion libraries to see if any are helpful in implementing (b). (d) implement something. -- William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
