finishing up report

git-svn-id: svn://anubis/gvsu@407 45c1a28c-8058-47b2-ae61-ca45b979098e

cs658/html/report.html

@@ -114,8 +114,8 @@
     <p>
         To create a scalable parser to read scene files according to
         a grammar that I supplied, I used the bison parser generator.
-        I chose bison because it is very portable and worked directly
+        I chose bison because it is very portable and has a C++
-        with my C++ code.
+        interface so I could interface it with the rest of my code.
         The parser produces a hierarchy of <tt>Node</tt> objects.
         Each <tt>Node</tt> object represents some part of the parse tree
         obtained from the scene description file.
@@ -164,7 +164,8 @@
         I ran "netstat -taunp" and saw that the TCP connections had
         data in their send queues.
         This meant that the program had already processed what it was
-        asked to process and was simply waiting for the network.
+        asked to process and was simply waiting for the network traffic
+        to be processed.
         I realized that the TCP implementation was waiting to accumulate
         data before sending it over the TCP connection.
         In order to deal with this, I used the <tt>setsockopt()</tt>
@@ -188,7 +189,7 @@
         I believe this did not work well because I was manually creating
         and managing threads with the pthread system in addition to
         trying to use OpenMP, which was probably implemented by the
-        compiler using pthreads.
+        compiler using pthreads as well.
     </p>
     <p>
         Because OpenMP did not work to utilize every core on a worker
@@ -208,6 +209,35 @@
 
     <a name="evaluation" />
     <h4>Evaluation</h4>
+    <p>
+        I designed the raytracer itself in the first half of the semester
+        and got it working well using a sequential approach.
+        In the second half of the semester I added the task distribution
+        infrastructure which allowed the raytracer to break up the
+        work of rendering an entire scene into tasks of a small size.
+        These tasks were then dispersed among slave processes which
+        were launched using the distribution infrastructure.
+        One slave process was created for every processor on each host
+        involved in the render.
+        I tested this design in the Grand Valley EOS computer lab.
+        A serial render of a given scene on eos01 took 38 minutes.
+        When I rendered it using the distribution infrastructure on
+        all 24 nodes (64 cores), it took about 38 seconds.
+        This is a speedup of about 60 times.
+    </p>
+    <p>
+        I was able to implement my program very closely with my original
+        design.
+        There are some features related to the raytracer (not the
+        distribution part of it) that I was not able to implement, but
+        that I am planning to add at a later time.
+        Such features include other Light types such as a directional light,
+        a jitter parameter to lights that can be used to render soft shadows,
+        a scene pre-parser that would allow shape definitions and looping
+        with variables to create patterns of objects,
+        texture support on the surfaces of objects,
+        and light refraction through semi-transparent objects.
+    </p>
 
     <a name="futurework" />
     <h4>Future Work</h4>
@@ -218,10 +248,11 @@
         of processors detected
         on the slave node.
         This has the disadvantage that the scene-file is parsed and
-        initialization is redone for each of these processes.
+        initialization is repeated for each of these processes.
         This time could be saved by an implementation that instead
-        created another thread with <tt>pthread_create()</tt> after
+        created more threads with <tt>pthread_create()</tt> after
-        parsing the scene file and building the scene.
+        parsing the scene file and building the scene, and then
+        used these threads to split up the work for a given task.
     </p>
 
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