CS 180 - Assignment #4

Information

Do not use pthread_exit() in your code. There is a known issue with valgrind and it causes problems with leak checking. Instead of pthread_exit(), just use a return statement in your code. If you fail to follow these instructions, you will lose points when valgrind complains. Also, make sure you check the return values of the pthreads functions to make sure they were successful. The grader will deduct points if you haven't checked the return values (regardless of whether or not they succeeded).

• Handout
• main-thread.c (HTML) This is a skeleton to get you started. You'll need to modify it. You can change most anything you want but don't change the print_array function because you won't diff correctly if you do. Also, you must document (Doxygenize) all functions, including main, even if you didn't write the functions.

• Command line to compile the program:

  gcc -g -O -Wall -Wextra -ansi -pedantic -pthread main-thread.c matrix-thread.c -o matrix-threads
  

• To run the program, type this at the command line:

  ./matrix-threads matrix.txt
  

  where the parameter is the name of a text file that has the matrix in it

• Sample output for a small 3x3 matrix:

         1       2       3
         4       5       6
         7       8       9
  
        30      36      42
        66      81      96
       102     126     150	
  

• Here is a program to generate random matrices for use as input for this assignment. For example, if you want a 5x5 matrix with values ranging from -20 to +20, you would run it like this:

  ./gen_matrix 5 -20 20
  

  and you would see something like this:

  5
        16      14      16      12      15
         8       8     -16     -19      -6
       -17      -2      20      11       5
       -15      -6     -10       5      19
        16      -4      16      10       5
  

  You would redirect the output into a file for use by the program:

  ./gen_matrix 5 -20 20 > mat5.txt
  

• Sample output for the above matrix by running: parent-matrix mat5.txt

        16      14      16      12      15
         8       8     -16     -19      -6
       -17      -2      20      11       5
       -15      -6     -10       5      19
        16      -4      16      10       5
  
       156     172     472     312     539
       653     346    -226    -387    -399
      -713    -380     130     159      91
       111    -344     -90      39     -49
      -118      80     620     544     559
  

• Sample output for a random 16x16 matrix
• Random 20x20 matrix
• Matrix references:
• Refresher on matrix multiplication
• Another refresher.
• Online matrix multiplier
• Using script

You need to show me that you actually compiled and ran your program, and used diff to make sure your output is correct. After you've finished coding and testing everything and are sure everything is correct, use the script command to make a text file of your session. From the bash shell in the directory you've setup to test with, run these commands:

script
date
uptime
echo FIRSTNAME LASTNAME
pwd
whoami
uname -a
cat /proc/cpuinfo
cat /proc/meminfo
gcc -g -O -Wall -Wextra -ansi -pedantic -pthread main-thread.c matrix-thread.c -o matrix-threads
./matrix-threads mat16.txt | tee output.txt
diff --strip-trailing-cr output16.txt output.txt
valgrind -q --leak-check=full --show-reachable=yes --trace-children=yes --tool=memcheck ./matrix-threads mat16.txt
doxygen
ls -al html/
ls -al latex/

Then, press Ctrl-D to end the script session. A file named typescript was created with all of the commands and output. Replace FIRSTNAME and LASTNAME with your real first name and last name. This is how you get your name in the typescript file. Consult the man pages if you want more information on script.

Additional information

• Example for a 3x3 matrix:

Squaring this:

1       2       3
4       5       6
7       8       9

Results in this:

 30      36      42
 66      81      96
102     126     150

Aftering the main thread allocates the memory and reads the input matrix from the file into the memory:



After the main thread allocates memory for the resulting matrix:



This is the how the first thread calculates the value:

Row 0:



Column 0:



Writes to first integer in the result matrix:



This is how the 6th thread calculates the value:

Row 1:



Column 2:



Writes to 6th integer in the result matrix:



Aftering each thread has written its result to the matrix: