On 02/13/2013 11:14 AM, Rob Weir wrote:
On Wed, Feb 13, 2013 at 10:43 AM, Pedro Giffuni <p...@apache.org> wrote:
FWIW;
----- Messaggio originale -----
Da: Andrew Douglas Pitonyak
Of course, had I implemented quaternion math using Boost, no one would be
complaining. :-P
Pedro.
[1] http://bikeshed.org
Do it, do it, do it; PLEEEEEEEEEEEEEESSSSSSSSSSEEEEEEE..... :-)
Quaternions are cool.
I think it is easy, and likely a nice exercise for someone wanting to start
AOO development. Perhaps GSoC material.
After that, how about interval arithmetic! I think that is even more fun!
I don't know about that, sorry ;).
It could be used as a form of sensitivity analysis. A value in a
spreadsheet might be a known value, like a sales tax rate, that is
certain. But you also might have other values that are measurements
with measurement error, or estimates with confidence levels. If you
treat these unknowns as intervals then you can get some interesting
results:
http://en.wikipedia.org/wiki/Interval_arithmetic
Even better is to allow cells to have an associated distribution,
e.g., normal with given mean and variance, uniform within a given
interval, etc. If you also have the ability to define covariances
between the variables then you can do a monte carlo simulation to
determine the distribution of the result cells. Very powerful
technique.
Today, conceptually at least, a spreadsheet commonly has these
different "layers" that are associated with each cell:
1) Contents, e.g., a number, string, formula, blank.
2) A value, e.g., the evaluation of the formula, or the value of a literal.
3) A format, e.g., currency 2 decimal places
4) A style, e.g., green background, bold text
There is a lot we could do if we made it easy for extension authors to
add more "layers" to a spreadsheet. For example, a layer for
dimensions and units (meters, inches, foot-pounds/second, etc. ) would
allow error checking for incorrectly mixing dimensions as well
automatically converting units. So adding a cell containing seconds
to one containing meters would be flagged as an error. But adding
meters and feet might be permitted and a conversion factor
automatically made. You could also imagine a layer for probability
distribution, etc.
There is no need for the core of Calc to understand the custom layers
other than to respect them during editing operations, e.g., a cut and
paste operation brings along contents, format, style, as well as any
custom layer metadata.
Sadly, I expect it would be difficult to pull-off, but, if you did, then
you could use that for all sorts of things; intervals, complex numbers,
etc.
--
Andrew Pitonyak
My Macro Document: http://www.pitonyak.org/AndrewMacro.odt
Info: http://www.pitonyak.org/oo.php
