The ray.c program is the basis for the two progams you need to write
for assignment 1. Copy ray.c to data.c and add the Pthreads to make it
a data parallel program. Copy ray.c to task.c and add the Pthreads to make
it a task parallel program.
Usage: [ray -s <int] [-t <int] [-o]
-s Indicates the scale of the output image. The default scale is 1 which
results in an image of 800x600 pixels. If -s is used then each dimension
will be multiplied by that amount. A scale of 2 will result in an image
that is four times the size of the original image.
-t Indicates the number of threads used to process the image. The variable
threads stores this value. You should use to indicate how many threads
will be created. You will need to write the Pthread code.
-o A flag which writes the ray traced image to an output file named
image.ppm. When runing the final timing tests you don't need to create
the output file. When adding the Pthreads to the progam you should
examine the output file to ensure that it is correct and that the
introduction of threads has not broken the program.
NOTES
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1. There is no threading code in the program. It is part of the assignment
to add the Pthreads to the system and to use the -t command line argument
to control the threads.
2. There are comments in the ray.c file indicating where you need to begin
and end recording the time used by the rendering system. They look like this:
/*** start timing here ****/
/*** end timing here ****/
These have been chosen so emphasize the timing of the computational elements
of the ray tracer and to avoid timing elements of the program which will not
benefit from the use of Pthreads (such as initializing variables and memory,
and writing the output file). Print your timing informaiton to the
screen (stdout) after the ending comment.
3. Do not change the command line arguments for -s, -t, and -o. The TA will
use them to test your progam and if they do not work as expected then he
will deduct marks.
