# Library hierarchy, contd.

**Dylan Thurston
**
dpt@math.harvard.edu

*Thu, 24 May 2001 08:32:59 -0400*

On Wed, May 23, 2001 at 05:43:01PM +0100, Simon Marlow wrote:
>* Data
*>* Complex -- H98
*
This seems decidedly out of place here: complex numbers are not
interesting as a data structure, but as a mathematical construct.
(I.e., the instance of Num is the interesting part.)
Part of the motivation for a "Mathematics" hierarchy is to have a
natural place where, e.g., "Complex" would belong.
>* Data
*>* Int
*
This seems somewhat less out of place, since, IIRC, the functions in
this library deal with low-level representation.
>* Algebra
*>* DomainConstructor -- formerly DoCon
*>* Geometric -- formerly BasGeomAlg
*
>* Numeric -- exports std. H98 numeric type classes
*>* DSP
*>* FastFourierTransform
*>* Noise
*>* Oscillator
*
You make a good point that these current libraries do not fit all that
well under "Mathematics". Maybe we should keep "Numeric" and create a new
"Mathematics" hierarchy which would contain:
- the std. H98 classes. [Incidentally, I agree with Sergio
Mechvelliani that the "Num" class is badly named. I would vastly
prefer to call the class "Ring".]
- the Complex class
- Mechvelliani's classes
- arbitrary precision arithmetic
- matrix classes
Maybe "Computational" would be a better name than "Numeric"?
Best,
Dylan Thurston