CSE3221 (Summer 2013) Assignment #1

You have to work individually. You are not allowed to view or exchange documents with your peers. We treat all sorts of cheating very seriously. Do not copy code from anywhere, even as a `template''. No late submission will be accepted. Your work will be graded based on: i) correctness of programming logic; ii) clarity of your code and your coding style; iii) whether your code follows the specification. It is your responsibility to explain clearly every detail you do in the code with appropriate comments to avoid any possible confusion in marking.

This assignment is due 19:00, June 19, 2013.

You are required to process several data sets to calculate the overall mean of all data samples. Each data sample is a floating-point number. Each data set consists of many data samples and each data set is stored in a file. The file format is that all data samples in this data set are separated by whitespace in the file. As example, we have posted three data sets on the course Web: dataset1, dataset2, dataset3, for your reference. However, your program should be able to process any number of data sets.

• Write a C program, called process.c, to do the calculation concurrently with multiple processes. The program first reads file names of all data sets from the command line. For each data set, it creates a child process. Each child process first reads all data from the file, and calculates the mean and the sample count of the data set, and sends the mean and the count to the main process via a Unix pipe. The main program first collects all means and counts from all children processes and waits for all children processes to finish. At last, the main program calculates the overall mean of all data sets based on the received means and counts and prints out the mean to the standard output.

• Write a Pthread C program, called thread.c, to repeat the above calculation concurrently with multiple threads. The program creates a thread to process each data set. Each thread calculates the mean and the count for each data set and passes them to the main program. The main program waits for all threads to finish and calculate the overall means based on the received means and counts, and prints out the result.

Your programs should compile as follows:

cc –o prs process.c

cc –o thr thread.c –lpthread

And the programs should run as follows (all datasets are provided as command line arguments):

prs dataset1 dataset2 dataset3

thr dataset1 dataset2 dataset3

What to submit?

Submit two C programs using the following commands:

submit 3221 a1 process.c

submit 3221 a1 thread.c