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→Assignment 1
This function, like others in the CImg_demo.cpp library uses the <CImg.h> library. This is a massive library that contains functions and routines responsible for displaying and preparing the environment for Image and Video processing. My function 'Filled Triangles' uses this library and its resources extensively.
Compilation with profiling on Mac OSX:
'''g++ -o CImg_demo CImg_demo.cpp -O2 -g -pg -I.. -Wall -W -ansi -pedantic -Dcimg_use_vt100 -I/usr/X11R6/include -lm -L/usr/X11R6/lib -lpthread -lX11'''
I have successfully built this application on the following platforms: Windows 7, OpenSuse linux and Mac OSX Lion.
=== Summary of Findings ===
The execution of the program takes roughly 3.10 - 20 seconds (depending on how long you are measuring the calculations of triangle animations). it should be noted that this application initially was an application that relied upon user input for execution and for termination. I have modified this initial behavior by ensuring the while loop (which generates the triangles) executes only for a maximum of 1000 iterations. The time measured in this assignment is for every 1000 iterations of this loop.
=== Profiling Results ===
The results if the initial profile shows that the execution time is most greatly consumed when drawing the triangles out to the screen one at a time. It seems like this can be optimized by offloading this drawing to n threads based on n triangles to be drawn. But this is subject to change because of any additional complexity that may be introduced that may include interoperability with both the GPU and CPU.
There is another for loop which sets the dimensions for each triangle one by one in linear time O(n ). This process can also be out-sourced to the GPU in n threads for n triangles. I would need to determine if this process also involves interoperability between the CPU and GPU.
The complexity of the entire program is O(n^3). There is a for loop for setup, a while loop for accepting user input and another for loop for drawing the triangles.
Also the times recorded can be increase if the maximum loop iterations increase ie: 10000,100000,1000000. This will identify the same relationship but with higher task time.
=== Potential Parallelization Candidates ===
=== Amdahls Law Calculations ===
Since there are 100 Triangles generated then we can theoretically create 100 threads for each triangle. The draw_line, draw_triangle, and draw_image functions take up 16 percent(0.38 + 0.08 + 0.06 / 3.10) of the execution time of the application in seconds. Plugging that into the equation using 100 cores we get:
S100 = 1/ 1 - 0.16 + 0.16 / 100
= 1.18 seconds or 1.2 seconds speedup rounded up PER 1000 iterations of the while loop to draw these triangles.
Will I work on this Project?
If I can optimize this function or any other function within the CImg library I will continue with this project. If it is not possible to optimize this project within the given time of the course then it will be difficult to continue on with this project and I will have to work with someone else's project. But my initial plan is to continue with this project unless I am told otherwise.