Fast Blur Challenge

Implement the blur() function in blur.c. Make it as fast as possible.

Rules

1. Only the following thrid party code may be used
   • C Standard Library
   • C POSIX Library
   • Intrinsics
2. ...

DEADLINE

24 Jan 17:00pm UTC.

Target Platforms

The base target is the cs50x codespace:

• x86_64
• Linux
• 1 core; 2 threads
• No GPU

However, once solutions have been submitted, any participant may bench them all locally, widening the target platforms to something more like:

• x86_64
• Linux/BSD
• Multi-core; multi-thread
• 1+ GPU

Build

$ make [release]
$ make debug
$ make -B release

Using -B will be necessary to force a rebuild if switching between release and debug when no changes have been made to filter.c|h since the last build.

Batch Benchmarking

N.B. It's not pretty but should hopefully work.

If you have multiple versions of blur.c, each with a unique filename, we can bench them one after another as follows:

$ make bench-all
mkdir -p bench
cp filter.c filter.h Makefile stb_image.h bench
mkdir -p submissions
Place one or more versions of 'blur.c' into submissions/

This will create two new directories, bench/ and submissions/, with the former receiving a copy of the essential build files. Do as suggested and copy the necessary files into submissions/. Then run the command again.

$ cp blur.c submissions/
$ make bench-all
Benching submissions/blur.c...
clang -march=native -std=c18 -Wall -Wextra -pthread -O3 -DNDEBUG -o filter filter.c -lm
Calling function blur...finished.
Elapsed time: 0.00000 seconds