Readme file for hw#1 program

Purpose:

This homework is intended to study the measurement of FLOPs/sec and memory access patterns in different configurations.

Usage:

srun ./computing_sum [iteration] srun ./computing_sum_hardcoded srun ./structured_mem [iteration] srun ./unstructured_mem [iteration]

If the user gives an argument "iteration" on the command line, the program will use that value, interpreted as an integer, and calculate a summation number up to "iteration" times.

The program will first measure the current time, then run "iteration" number of times to formulate the sum, then measure the current time again, then compute and print the difference in time and the sum.

Default build instructions:

% cd chrono_timer # contains the source file and CMakeLists.txt file

% mkdir build

% cd build

% cmake ../ # cmake generates lots of output OR % cmake ../ -DCMAKE_CXX_FLAGS_RELEASE="-O0" # for -\O0 optimization

% make # to build the program

Additional build options

Optimization level: as written in the CMakeLists.txt file, the gcc/g++ compiler is provided an optimization flag of -O0, which will effectively disable most optimizations.

To change this behavior, uncomment the line in CMakeLists.txt:

#set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3")

and comment out the line: set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O0")

and then repeat the Default build instructions above, but first delete everything (\rm -rf) in the build directory (cmake retains a memory of previous runs and that memory can sometimes be unpredictable..you're best off just deleting everything and starting fresh if you change anything in the CMakeLists.txt file)

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