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From "Phil Steitz" <p...@steitz.com>
Subject Re: [math] proposed ordering for task list, scope of initial release
Date Tue, 10 Jun 2003 13:42:25 GMT
Al Chou wrote:
> --- Brent Worden <brent@worden.org> wrote:
> 
>>>-----Original Message-----
>>>From: Phil Steitz [mailto:steitzp@yahoo.com]
>>>Sent: Friday, June 06, 2003 12:21 PM
>>
> [deletia]
> 
>>>* Exponential growth and decay (set up for financial
>>>applications) I think this
>>>is just going to be a matter of finding the right formulas to add
>>>to MathUtils.
>>> I don't want to get carried away with financial computations,
>>>but some simple,
>>>commonly used formulas would be a nice addition to the package.
>>>We should also
>>>be thinking about other things to add to MathUtils -- religiously
>>>adhering to
>>>th guiding principles, of course.  Al's sign() is an excellent
>>>example of the
>>>kind of thing that we should be adding, IMHO.
>>
>>Things that might be added:
>>Average of two numbers comes up a lot.
> 
> 
> Do we muddy the class hierarchy by putting such a thing into MathUtils rather
> than the stat subtree?
> 
> 
> 
>>Something similar to JUnit's assertEquals(double expected, double actual,
>>double epsilon).
> 
This is a good idea.

> 
> Is JUnit's license (http://www.opensource.org/licenses/ibmpl.php) Apache
> compatible?
> 

I think that Brent is talking about defining a new function called 
something like approximatelyEquals() that returned a boolean.  The 
signature, semantics and implementation of this would be different from 
JUnit.

> 
> 
>>Simple methods like isPositive, isNegative, etc. can be used to make boolean
>>expressions more human readable.
> 
> 
> I'm willing to build those two on top of sign (I'm so generous with my coding
> time, eh? <g>).  Are those two sufficient?  sign treats 0 as positive, which
> may not be desirable.
> 
+1 (especially the part about your time :-)

> 
> 
>>Some other constants besides E and PI: golden ratio, euler, sqrt(PI), etc.
> 
> 
> That would be nice, though we should consider which ones are really needed
> generally.  I personally love the lore of constants, of which there are more
> than you might imagine (see
> http://mathworld.wolfram.com/topics/Constants.html).
> 
> 
> 
>>I've used a default error constant several places.  It would be nice to come
>>up with a central location for such values.
> 
> 
> Or at least define a consistent interface that could be implemented by whatever
> needs that.
> 
> 
> 
> Al
> 
> =====
> Albert Davidson Chou
> 
>     Get answers to Mac questions at http://www.Mac-Mgrs.org/ .
> 
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