Re; finding euclidean distance,better code?

[Maurice LING]

Hendrik van Rooyen wrote:
> On Saturday 29 March 2008 03:09:46 Steven D'Aprano wrote:
>> On Fri, 28 Mar 2008 16:59:59 +0100, Robert Bossy wrote:
>>> Gabriel Genellina wrote:
>>>> That's what I said in another paragraph. "sum of coordinates" is using
>>>> a different distance definition; it's the way you measure distance in a
>>>> city with square blocks. I don't know if the distance itself has a
>>>> name, but
>>> I think it is called Manhattan distance in reference of the walking
>>> distance from one point to another in this city.
>> You know, there are other cities than Manhattan. Some of them even have
>> streets and blocks.
> 
> Sorry about having to dispel your illusions, but -
> 
> In Printed Circuit Board Layout jargon, the 'manhattan distance' is
> the sum of the distances along the orthogonal axes between
> two points on the board that should be connected.
> 
> The sum of all such distances is an idealised minimum for the
> total track length on a double sided board, given that it were 
> possible to lay all tracks with segments connected by vias,
> making strictly increasing progress in the desired direction,
> by laying x direction tracks on the one, and y direction tracks 
> on the other side of the board without having to "backtrack" 
> - i.e. having to "dodge around" obstacles, thereby adding 
> "overshooting" segments of track.
> 
> (A via is a through plated hole that connects copper traces or 
> tracks on opposite sides of the board) 
> 
> So I have met the beast, but I have no concept of its origin,
> other than the mind numbing regularity of the layout of the
> suburb of the city after which it seems to be named -
> For all I know 'manhatten' could be a native american word that
> means "net".
> 
> Have you noticed that when people say "Sorry.....but...." they are 
> not normally sorry at all?
> 
> :-)
> 
> -  Hendrik
> 

Manhatten distance is also known as "taxicab distance" or "city block 
distance" - the average distance of getting from point A to point B in a 
city with roads laid out as grids.

maurice