> An example of a simple plan is a simple "find" plan:
> iterate through the set
> test each set member to see if it is the target; if it is, end the iteration
Most computer scientists would (hopefully) call this the linear search algorithm --
and therefore be very worried about using it
because it is O(n), proper searching should be O(log(n)) (binary chop and binary tree
search) or O(1) (hash table).
So what is the relationship between a plan in the above sense and an algorithm?
I had always thought of plans as more implementation related rather than algorithm
related but then maybe that is my problem?
Interestingly, and why I readdressed this old (2 days:-) email, is that in languages
like C++ and Java (also C# I guess) you can
say:
C++
thing aThing ;
set<thing> x ;
...
bool isIn = x.count(aThing) != 0 ;
Java
Thing aThing ;
Set s = new HashSet () ;
...
boolean isIn = s.contains(aThing) ;
This means that the issue of finding is not a general programmer issue in these
languages (but is thing that the developer of the
type must deal with). It never ceases to amaze me how many professional programmers
coming from C or other languages to C++ and
Java fail to make the switch from always implementing all algorithms to actually using
the features available in a given type.
I think there is an issue here that needs to be addressed: How to support the
professional programming community in their duty
to keep themselves properly updated.
The issue for the PPIG community is, I guess, how to build information and knowledge
about how to transfer algorithm and
programming idioms from one language to another
Of course, if we knew what the cognitive issues were associated with each language and
how to transform between them it would
help.
Russel.
======================================================================
Professor Russel Winder Professor of Computing Science
Department of Computer Science Fax: +44 20 7848 2851/+44 20 7848 2913
King's College London [EMAIL PROTECTED]
Strand, London WC2R 2LS, UK http://www.dcs.kcl.ac.uk/staff/russel/
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