[Om] Questions about representing units

Jonathan Stratford jonathanstratford at hotmail.com
Sat Feb 21 21:59:24 CET 2009

Hi Christoph,

By "service", are you envisaging a proper web service? I don't know much 
about those, and my program isn't one -- just a standard exe with a PHP 
front-end. As such I'm not sure how easily you could integrate it into 
anything else. You're welcome to try though!

I'm happy to give you my program...I've actually fixed the bug that caused 
the problem you mentioned earlier, although I've by no means completely 
tested the changes. I'll send that to you separately in a minute, as it's 
probably not fair to spam everyone with it! It just runs under mono quite 
happily -- in actual fact klein is a Mac, but I guess mono runs the same 

Using WinSCP also occurred to me this evening, but klein seems to be down, 
so can't get very far!

Yes, there's another student continuing the work, but I'm not sure what he's 
doing in terms of where he's extending my program. I hadn't thought about 
releasing the code under licence..no idea how I'd go about doing so, but it 
might be a good idea if I could find out what it entails.


----- Original Message ----- 
From: "Christoph LANGE" <ch.lange at jacobs-university.de>
To: "Jonathan Stratford" <jonathanstratford at hotmail.com>
Cc: "Professor James Davenport" <jhd at cs.bath.ac.uk>; "OpenMath" 
<om at openmath.org>; <mdt22 at bath.ac.uk>; <jap at cs.bath.ac.uk>; 
<jonathan.stratford at alumni.bath.ac.uk>; "Jana Giceva" 
<j.giceva at jacobs-university.de>
Sent: Saturday, February 21, 2009 7:57 PM
Subject: Re: Questions about representing units

Hi Jonathan,

On Saturday 21 February 2009 14:46:31 Jonathan Stratford wrote:
> >BTW, does your unit converter
> >(http://klein.activemath.org:90/~jonathan/units/converter.php) support
> > such compound units for which no explicit symbol has been defined?
> Yes, it can cope with many of these (it can't cope with all of them as the
> algorithm's by no means perfect).
> ...
> 17.3 millimetre per nanosecond sqrd to mile per hour sqrd
> 6 ounce inch per minute sqrd to kilogramme metre per second sqrd

OK, thanks!  The reason for my questions is not that we need a perfect unit
conversion service, but some nice service on the web that we can integrate
with our (inter)active documents for demo purposes.  Then, depending on the
acceptance of that idea, the next requirement would be a better unit
conversion service ;-)

> For some reason, I can't get the online version to load

It worked for me yesterday, but not today.  Anyway: Is there any way to 
your source code, or the compiled version?  Not sure what one needs for
running this on Linux (just a .NET environment like Mono?), but I suppose 
klein.activemath.org is a Linux server as well.

> >> 1 hour to second is incalculable.
> ...

I see -- thanks for your explanation!  Anyway, we don't require this
conversion to work at the moment, but it just struck me that such a simple
conversion was reported to be impossible.

> "Something that needs considering in OpenMath, but which has quite
> wide-ranging consequences for our system is whether it is correct for a
> unit name to appear in two different CDs, both to represent the same unit,
> as with second, or a different unit. This affects how the units are stored
> and looked up."

For general OpenMath symbols, this has to be possible, of course, but I see
that it might be something between bad style or illegal for OpenMath symbols
that represent units.

> I have no way of updating the version on klein.activemath.org (I never had
> FTP access, only scp, so I used my uni webspace to copy from). It has just
> occurred to me that I could possibly do it through cygwin, so I will try 
> to
> give it a go later on -- but it seems the server is down currently.

How about WinSCP?  That's a more convenient alternative.

> >Is there any better place for reporting this bug?
> I imagine I'm the only one worth reporting bugs to, as I don't think 
> anyone
> else is likely to work on it.

Didn't James mention one other person who might possibly continue this
project?  Or, on the other hand, how about releasing your code under an open
source licence and hoping for somebody else to help you?

Thanks again for your help!



Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype 

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