CSE 5306-2
Lab Insights
Rapid Prototyping
• Agile software designers do the hardest parts of
their projects first.
• Software analysts very quickly develop a series of
simple models (rapid prototypes) of a customer’s
concepts to elicit her requirements.
• Nontechnical customers cannot clearly verbalize
technical requirements to software designers.
(Nor can software designers paint portraits.)
• But customers know what they like, when they
see it. And they can conceptually verbalize what
is wrong with each prototype demonstration.
MATLAB Simulations
• Start with those parts of each performance
demonstration that are 1) easiest to code and
2) the customer feels are most important.
• Lab 1 example:
– A simple script (not a function) with fprintf (or
disp) functions would earn you about 80%.
– disp(‘myBalance yourBalance myChex’)
– disp(‘100
0’)
– disp(’40
0
150’)
– disp(‘Overdraft!’)
– disp(’20
20
20’)
Bridge to the Software Designer
• The designer says, “But you have only written a test case
and its correct results. …How does the system work?”
• Answer: rapidly prototype the logic in function(s), most of
which already appear in MATLAB’s very extensive library.
(Thinkers always should browse “Help” diligently!)
• Lab 1 example—repeatedly invoke the following function in
the Command Window to earn a 85% grade:
–
–
–
–
–
–
–
–
function [ myAcct urAcct ] = banksvr( myChex )
urAcct = urAcct + myChex
% your deposit…
myAcct = myAcct – myChex
% …matches my withdrawal
If myAcct < 0
% transaction failure!
urAcct = urAcct – myChex
% back out the deposit
myAcct = myAcct + myChex – 60 % back out the withdrawal
end
end
Software Reuse
• MATLAB is the rapid prototypers’ Wikipedia…!
(Every part of your next system simulation
already has been implemented by other
systems analysts hundreds of times.)
• Lab 1 example:
– One of MATLAB’s GUI templates already includes
two labeled textboxes and two buttons. (You need
only one more button, exactly like the others.)
– Make a few cosmetic changes, and press the
green triangle “GO” button to automatically
generate your GUI’s code and earn a 90%.
Put It All Together
• Integrate all of your lightly-adapted MATLAB
stock functions to achieve the customer’s desired
performance, in a way that also informs the
software designer.
• Lab 1 example—insert function invocations
directly into the GUI code to earn a 95%:
–
–
–
–
–
–
% “100” button paragraph:
myAcct = 100
urAcct = 0
% “20” button paragraph:
[ myAcct urAcct ] = banksvr( 20 )
Etc.
Make the Customer Smile
• Clean up the GUI, clarify the Command Window test
report, fully test the function(s), etc. (See MATLAB’s
extensive library of very professional demonstrations
on your computer and at www.Mathworks.com .)
• Ensure that every known requirement is demonstrated.
• Lab 1 example, which earns 100%:
– Transactions’ classic ACID features are clear here.
– You and I perceive this collection of independent
computers (i.e., the distributed system of two GUI clients
and bank server) as a single coherent system.
– Several distributed system transparencies are clearly
apparent.
Summary
Take these 5 steps in your next rapid prototyping effort:
0. (Doing absolutely nothing earns 70% by default.)
1. A MATLAB script that simply uses fprintf instructions to
print a demonstration of the prototype's required
performance in the Command Window earns ~80%.
2. Also allocating those fprintf statements to a collection of
interacting functions helps out your software developers
and earns ~85%.
3. Also integrating those functions with any necessary
MATLAB functions earns ~90%.
4. Also tidying up your code and making its nontechnical
customer demonstration abundantly clear earns ~95%.
5. Also making the demo clearly describe the textbook
concepts, for which the lab was created, earns ~100%.