Re: [OctDev] Octave interface to GNU units

[Paul K. <pki...@us...>]

I've added this even though it is not ideal.

An ideal solution would allow you to say e.g., "4 kg * 2 m / 8 s" and=20
return a value of "1 kg m/s".

I doubt an ideal solution is possible, since math layout is two=20
dimensional, dependent on font and on fine details of spacing between=20
tokens.  Even then it is still ambiguous.

You could add a units type which is a number, name pair.  By writing=20
"4*kg*2*m/(8*s)" with kg,m,s as predefined unit variables the ambiguity=20=

goes away.  Unfortunately this consumes a large number of desirable=20
variable names such as m and s.  Each unit would need multiple versions=20=

to allow for every possible standard SI prefix.

You could instead rewrite octave's reader to require a comma between=20
matrix elements, and treat a number followed by text as space, but you=20=

have approx. zero chance of that patch being accepted.

You could write units as a separate type with a constructor that parses=20=

string expressions and returns value-unit pairs.

Any other suggestions?

- Paul

On Dec 29, 2005, at 9:35 AM, Carl Osterwisch wrote:

> Here's a version with a more impressive demo involving mass.  Let me
> know if units version 1.0 does not have lb, oz, and kg.
>
> -Carl
>
> --- Paul Kienzle <pki...@us...> wrote:
>
>> For some reason the MacOS 10.3 version of units is missing things
>> such
>> as
>> Pa for pascals (it thinks it is Peta-atto) and J for joules, so the
>> demo
>> doesn't work very well.  I don't know why they use an ancient
>> version.
>>
>> $ units -v
>>
>>    units version 1.0  Copyright (c) 1993 by Adrian Mariano
>>
>>
>> On Dec 28, 2005, at 10:02 AM, Carl Osterwisch wrote:
>>
>>> Hello,
>>>
>>> Here is my submission for an octave interface to the GNU units
>> program
>>> (http://www.gnu.org/software/units) which is immensely useful in
>>> engineering calculations to convert from one measurement to
>> another.
>>> The benefit of using this octave function over hard coded constant
>>> conversion factors is cleaner, more maintainable code.
>>>
>>> I have included demo and test procedures at the bottom.  This
>> should
>>> fit nicely in the "mapping" subdirectory of octave-forge which
>> already
>>> contains functions to convert between angular measurements.
>>>
>>> Please let me know if you have any comments or questions.
>>> -Carl
>>>
>>>
>>>
>>>
>>>
>>> 	=09
>>> __________________________________________
>>> Yahoo! DSL =96 Something to write home about.
>>> Just $16.99/mo. or less.
>>> dsl.yahoo.com
>>> <units.m>
>>
>
>
> 	=09
> __________________________________________
> Yahoo! DSL =96 Something to write home about.
> Just $16.99/mo. or less.
> dsl.yahoo.com
> <units.m>=