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Date:      Tue, 04 Aug 1998 07:57:08 +0100 (BST)
From:      Duncan Barclay <dmlb@ragnet.demon.co.uk>
To:        Terry Lambert <tlambert@primenet.com>, freebsd-chat@FreeBSD.ORG
Cc:        luoqi@watermarkgroup.com, reilly@zeta.org.au, jgrosch@mooseriver.com, shocking@prth.pgs.com, malte.lance@gmx.net
Subject:   Re: Fast FFT routines with source?
Message-ID:  <XFMail.980804075708.dmlb@computer.my.domain>
In-Reply-To: <199808031914.MAA00830@usr07.primenet.com>

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[moved to chat]

On 03-Aug-98 Terry Lambert wrote:

> To know "how FFT works", you have to know what this nasty
> numbers in the frequency-domain stand for and where they come
> from. Also you need to know why you are able to reuse
> intermediary calculation-results (bit-reversion/reordering).
> The answers to this questions are easy, when you have knowledge
> about unit-roots and exponentials. Unit-roots and exponentials
> are really not that hard, that they shouldn't be explained in a
> basic-level analysis or algebra book.

Speaking in general about engineering now, this is so true. However, there are
many people you just want to use it, get the job done, get paid, go home.
I work at an engineering consultancy where we basically design and build
digital communication equiment where the digits are carried over the air (so
802.11, GSM, DECT, PHS, DTV, HomeRF, Bluetooth...).
We have grown from 5 people 9 years ago to
about 120 engineers now. Last Friday someone needed some RF help and was
saying that the character of the engineers has changed such that the majority
are good in one sphere but don't like anything new, makes it difficult
to do work on new technolgoies... 
 
> 
> I consistently find Sedgewick's book useful; despite the title, it
> has very little direct relationship to C++ (or any other implementation
> language).

I have the Pacal version and have used it to write C, Tcl, Makefiles...

> In particular, if you ever want to know "what's Terry on about?"
> when I talk about "Hamiltonian Cycles" and "Warshal's Algorithm"
> and "O(3) Algorithms for Transitive Closure" and "Directed Acyclic
> Graph", this is the book to read.
> 

Yup, usual scenario is "what is Terry on about today, ho hum lets look it up in
Sedgewick (or The Daemon Book)".

Duncan
---
________________________________________________________________________
Duncan Barclay          | God smiles upon the little children,
dmlb@ragnet.demon.co.uk | the alcoholics, and the permanently stoned.
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