General Comments about Homework 4


    General
	Programs that segfault have been returned to be
	fixed. Without a grader I do not have enough time to debug
	your code. You need to make sure your program runs on
	hammer and other machines. I can help with debugging, if
	you are really stuck, but I cannot debug all the programs
	in this class.

        The experiment descriptions and results were a little short
        with many students. A plot or at least a table is a good
        way to explain things (instead of just reporting raw timing
        results). You also need to mention what machine you ran
        on, how many trials you did, how much the results varied
        (error bars), what OS was running, etc.


    Problem 1
	I really was hoping to see a graph here. Also, it makes
	sense to repeat the individual runs several times and
	report and average run time. Maybe do it on more than just
	one machine...

	The code fragment was supposed to show the time command,
	but it got cut off.


    Problem 2
	A plot showing both curves is probably the most illustrative
	and easy to explain. Since the result do not differ much,
	the explanation is that matrix initialization does not take
	much time.


    Problem 3
        I used these test cases:
	./ex_03 -p 9 -n 3
	./ex_03 -p 2 -n 4
	./ex_03 -p 4 -n 4
	./ex_03 -p 5 -n 3
	./ex_03 -p 5 -n 5
	./ex_03 -p 12 -n 6
	./ex_03 -p 6 -n 12


    Problem 4
        Most people put the lock/unlock pair in the right place
        and then observed a huge slow down. Some people forgot to
        update global_id and global_loc


    Problem 5
        Mostly Ok. Run the experiment and see if you can get
        wrong results!  ;-)