Well, I'm moving. New ppmx introduces many improvements, mostly it's about optimizations. Briefly, what's new:
I believe that with this version I'm into something. At least new ppmx easily beats ppmz2 at SFC with no tuning. Note that current ppmx is still quite basic - I still have no luck with SEE and other tricks that may move my compressor even further. Secondly, I only started experimenting with PPM algorithm. In the past, I've mostly experimented with LZ-based stuff (lzpx/quad/lzpm/balz). So PPM is relatively new for me. Yep, pimple/pimple2 was cool, but it's too heavy for practical use. Also, quad has a small PPM built-in... I mean I was very close but not really into PPM. Anyway, with ppmx I tried to avoid any LZ-based features, making it a pure context coder. Don't know what's next, but hoping ppmx will be supreme. At least version by version it becomes more competitive. I even think that ppmx is my best compressor so far. I simply tested it against quad/balz - balz may win due to it's EXE-filter built-in - ppmx has no filters, but quad beaten even with its EXE-filter, and it's about binary/executable compression. On text files ppmx outperforms all LZ-stuff with a huge gap. ppmx's text compression is close to pimple being extremely faster. I think it's nice!
- Improved and more complete an order-12 PPM model
- Reduced memory usage to ~280 MB
- Many optimizations and code clean-up