Comments on: Data Compression with the Burrows-Wheeler Transform http://marknelson.us/1996/09/01/bwt/ Programming, mostly. Sat, 13 Mar 2010 00:06:53 +0000 http://wordpress.org/?v=2.2.3 By: Mohan http://marknelson.us/1996/09/01/bwt/#comment-320123 Mohan Thu, 17 Dec 2009 11:43:09 +0000 http://marknelson.us/1996/09/01/bwt/#comment-320123 Can anyone please let me know how to run this whole set of codes to compress a file. I really want to compress a set of files using this bwt. But when I try executing it, I have no option of inputting files. Please help me out somehow. I'm really in need of it as I'm doing a dissertation based on it. Please people. Help me out. Regards, Mohan Can anyone please let me know how to run this whole set of codes to compress a file. I really want to compress a set of files using this bwt. But when I try executing it, I have no option of inputting files. Please help me out somehow. I’m really in need of it as I’m doing a dissertation based on it. Please people. Help me out.

Regards,
Mohan

]]> By: Mark Nelson http://marknelson.us/1996/09/01/bwt/#comment-318825 Mark Nelson Wed, 18 Nov 2009 20:39:18 +0000 http://marknelson.us/1996/09/01/bwt/#comment-318825 @arabcoder: I'm not really sure what you are doing or what your question is. - Mark @arabcoder:

I’m not really sure what you are doing or what your question is.

- Mark

]]> By: arabcoder http://marknelson.us/1996/09/01/bwt/#comment-318823 arabcoder Wed, 18 Nov 2009 20:32:34 +0000 http://marknelson.us/1996/09/01/bwt/#comment-318823 thank you for your answer, maybe I am doing something wrong thank you for your answer, maybe I am doing something wrong

]]> By: Mark Nelson http://marknelson.us/1996/09/01/bwt/#comment-318811 Mark Nelson Wed, 18 Nov 2009 14:46:28 +0000 http://marknelson.us/1996/09/01/bwt/#comment-318811 @arabcoder: I don't see much interesting in the stackoverflow comment thread. And yes, arithmetic coding will either equal or outperform Huffman coding. - Mark @arabcoder:

I don’t see much interesting in the stackoverflow comment thread.

And yes, arithmetic coding will either equal or outperform Huffman coding.

- Mark

]]> By: arabcoder http://marknelson.us/1996/09/01/bwt/#comment-318810 arabcoder Wed, 18 Nov 2009 14:33:56 +0000 http://marknelson.us/1996/09/01/bwt/#comment-318810 You said in your document that huffman cannot compress better than arithmetic coding but then take a look in this stackoverflow question http://stackoverflow.com/questions/1755624/request-for-comments-on-huffman-compression You said in your document that huffman cannot compress better than arithmetic coding but then take a look in this stackoverflow question

http://stackoverflow.com/questions/1755624/request-for-comments-on-huffman-compression

]]> By: Mark Nelson http://marknelson.us/1996/09/01/bwt/#comment-315615 Mark Nelson Thu, 24 Sep 2009 12:22:43 +0000 http://marknelson.us/1996/09/01/bwt/#comment-315615 @eric: RLE will not have a large effect on compression - it is in place mostly to prevent pathological sort times. If you leave it out, a file with enormously long repeated strings will take a long time to sort, but will still compress well. Doing RLE only and not Huffman makes no sense. - Mark @eric:

RLE will not have a large effect on compression - it is in place mostly to prevent pathological sort times. If you leave it out, a file with enormously long repeated strings will take a long time to sort, but will still compress well.

Doing RLE only and not Huffman makes no sense.

- Mark

]]> By: eric http://marknelson.us/1996/09/01/bwt/#comment-315585 eric Thu, 24 Sep 2009 07:06:52 +0000 http://marknelson.us/1996/09/01/bwt/#comment-315585 At the same time, do anyone has C source code for BWT? Could you send it to me or post the link? Thanks. Here is my email address:- alienchean@gmail.com At the same time, do anyone has C source code for BWT? Could you send it to me or post the link? Thanks.

Here is my email address:-
alienchean@gmail.com

]]> By: eric http://marknelson.us/1996/09/01/bwt/#comment-315582 eric Thu, 24 Sep 2009 06:08:41 +0000 http://marknelson.us/1996/09/01/bwt/#comment-315582 Thanks Mark for your prompt reply. Actually I am curious on the performance for BWT compression. Let say for the final stage compression, if we use only RLE or only Huffman coding, wil there be much differ on compression ratio wise? Because currently I am having a BWT source code which compress the input texts in this sequence. bwtsort->mtf->huffman. So I am thinking will it impact much on the compression ratio if I remove the huffman process and replace with RLE. -Eric Thanks Mark for your prompt reply.

Actually I am curious on the performance for BWT compression. Let say for the final stage compression, if we use only RLE or only Huffman coding, wil there be much differ on compression ratio wise?

Because currently I am having a BWT source code which compress the input texts in this sequence. bwtsort->mtf->huffman. So I am thinking will it impact much on the compression ratio if I remove the huffman process and replace with RLE.

-Eric

]]> By: Mark Nelson http://marknelson.us/1996/09/01/bwt/#comment-315534 Mark Nelson Wed, 23 Sep 2009 13:46:34 +0000 http://marknelson.us/1996/09/01/bwt/#comment-315534 @eric: "the BWT patent?" The basic BWT technology was not patented by the inventors, and their publication of the basics would have prevented any other parties from acquiring a patent. I am sure there are various block sorting patents covering refinements and tuning, but the basics of the algorithm have never been patented. - Mark @eric:

“the BWT patent?”

The basic BWT technology was not patented by the inventors, and their publication of the basics would have prevented any other parties from acquiring a patent.

I am sure there are various block sorting patents covering refinements and tuning, but the basics of the algorithm have never been patented.

- Mark

]]> By: eric http://marknelson.us/1996/09/01/bwt/#comment-315515 eric Wed, 23 Sep 2009 03:51:40 +0000 http://marknelson.us/1996/09/01/bwt/#comment-315515 Does anyone know if BWT patent is still valid? When is the expiration for this patent? Thanks. Does anyone know if BWT patent is still valid? When is the expiration for this patent? Thanks.

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