245 lines
11 KiB
HTML
245 lines
11 KiB
HTML
|
<HTML><HEAD>
|
||
|
|
|
||
|
|
<TITLE>Release Notes for LDPC-codes Software</TITLE>
|
||
|
|
|
||
|
|
</HEAD><BODY>
|
||
|
|
|
||
|
|
|
||
|
|
<H1>Release Notes for LDPC-codes Software</H1>
|
||
|
|
|
||
|
|
These notes describe all the stable public releases of this software. Old
|
||
|
|
and future releases can be obtained via
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
<A HREF="http://www.cs.toronto.edu/~radford/ldpc.software.html">
|
||
|
|
<TT>http://www.cs.toronto.edu/~radford/ldpc.software.html</TT></A>
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
The current development version is now maintained at
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
<A HREF="http://github.com/radfordneal/LDPC-codes">
|
||
|
|
<TT>http://github.com/radfordneal/LDPC-code</TT></A>
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<H2>Version of 2012-02-11.</H2>
|
||
|
|
This version has a few bug fixes and some minor new features. The major
|
||
|
|
change is that a source repository for the software is now hosted
|
||
|
|
at github.com, making it easier for people to create and release
|
||
|
|
their own versions of this software.
|
||
|
|
<OL>
|
||
|
|
<LI> Changed the copyright notice (in the file COPYRIGHT, and elsewhere)
|
||
|
|
to remove the requirement that my web site be referenced. (Nowadays,
|
||
|
|
I think users should have no problem finding the sources using a
|
||
|
|
search engine.)
|
||
|
|
<LI> Included a copy of the nrand48 routine from the GNU C library
|
||
|
|
in the rand.c module, to ensure that it is always available
|
||
|
|
and always the same. (This isn't so on some versions of cygwin.)
|
||
|
|
<LI> Added a -f option to encode and decode that forces flushing
|
||
|
|
after writing each block. Useful for allowing encode or
|
||
|
|
decode to be used as a server, reading and writing blocks
|
||
|
|
from named pipes.
|
||
|
|
<LI> Added a -z option for pchk-to-alist to suppress output of 0
|
||
|
|
row and column indexes that pad up to the maximum number used.
|
||
|
|
<LI> Documented the previously undocumented -t options for pchk-to-alist
|
||
|
|
and alist-to-pchk.
|
||
|
|
<LI> Changed alist-to-pchk so that it no longer requires zero indexes
|
||
|
|
that pad out to the maximum needed for a row or column (thanks
|
||
|
|
to Monica Kolb for suggesting this).
|
||
|
|
<LI> Changed mod2word type in mod2dense.c to uint32_t, to avoid
|
||
|
|
wasted space when long is 64 bits (thanks to Mathieu Cunche
|
||
|
|
and Vincent Roca for suggesting this).
|
||
|
|
<LI> Fixed bug in distrib.c affecting distributions with a single
|
||
|
|
number (thanks to Mike Vicuna for pointing it out).
|
||
|
|
<LI> Fixed bug in -t option for pchk-to-alist (thanks to Andrea Fontana
|
||
|
|
for reporting this).
|
||
|
|
<LI> Fixed references in the documentation to mod2sparse_multvec
|
||
|
|
that should be to mod2sparse_mulvec (thanks to Andrea Fontana
|
||
|
|
for reporting this).
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
|
||
|
|
<H2>Version of 2006-02-08.</H2>
|
||
|
|
|
||
|
|
The copyright notice has been changed in this release to no longer
|
||
|
|
restrict use to purposes of research or education. The new copyright
|
||
|
|
notice can be read <A HREF="index.html#copyright">here</A>. It is now
|
||
|
|
possible to create LDPC codes with varying numbers of checks per bit
|
||
|
|
(an extension based on work by Peter Junteng Liu). New programs for
|
||
|
|
converting to and from the <A
|
||
|
|
HREF="http://www.inference.phy.cam.ac.uk/mackay/codes/alist.html">alist
|
||
|
|
format</A> for parity check matrices, used by David MacKay and others,
|
||
|
|
have also been added.
|
||
|
|
|
||
|
|
<P>The following new features have been added:
|
||
|
|
<OL>
|
||
|
|
<LI> The <A HREF="pchk.html#make-ldpc"><TT>make-ldpc</TT></A> program can
|
||
|
|
new create LDPC codes with varying numbers of checks per bit. The
|
||
|
|
<A HREF="examples.html">examples</A> now include a code of this sort.
|
||
|
|
<LI> New programs <A HREF="pchk.html#pchk-to-alist"><TT>pchk-to-alist</TT></A>
|
||
|
|
and <A HREF="pchk.html#alist-to-pchk"><TT>alist-to-pchk</TT></A> have
|
||
|
|
been added, which convert to and from <A
|
||
|
|
HREF="http://www.inference.phy.cam.ac.uk/mackay/codes/alist.html">alist
|
||
|
|
format</A>.
|
||
|
|
<LI> A <A HREF="run-examples"><TT>run-examples</TT></A> script has been
|
||
|
|
added, which runs all the <A HREF="examples.html">examples</A> and
|
||
|
|
compares with the saved output that I obtained.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
|
||
|
|
<H2>Version of 2001-11-18.</H2>
|
||
|
|
|
||
|
|
This is a minor release, whose main purpose is fixing bug (1) below.
|
||
|
|
Also, this release has been tested and found to work with the <A
|
||
|
|
HREF="http://www.cygwin.com">cygwin</A> Unix environment that runs
|
||
|
|
under Microsoft Windows.
|
||
|
|
|
||
|
|
<P>The following new feature has been added:
|
||
|
|
<OL>
|
||
|
|
<LI> A new <B>-t</B> option has been added to
|
||
|
|
<A HREF="pchk.html#print-pchk"><TT>print-pchk</TT></A>, which
|
||
|
|
causes it to print the transpose of the parity check matrix.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
The following program module change was made:
|
||
|
|
<OL>
|
||
|
|
|
||
|
|
<LI> The behaviour of <A
|
||
|
|
HREF="mod2dense.html#invert_selected">mod2dense_invert_selected</A>
|
||
|
|
has been changed when the matrix has dependent rows. The result returned
|
||
|
|
contains the inverse of a sub-matrix in its initial columns. The contents
|
||
|
|
of the remaining columns up to the number of rows was previously undefined,
|
||
|
|
but these columns are now set to contain zeros. This was done to fix
|
||
|
|
bug (1) below.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
The following bugs were fixed:
|
||
|
|
<OL>
|
||
|
|
<LI> A bug has been fixed in
|
||
|
|
<A HREF="encoding.html#make-gen"><TT>make-gen</TT></A>
|
||
|
|
which sometimes
|
||
|
|
produced invalid `dense' or `mixed' generator matrices when the parity
|
||
|
|
check matrix had redundant rows.
|
||
|
|
The `sparse' generator matrices were not affected. The output of the
|
||
|
|
<A HREF="ex-dep"><TT>ex-dep</TT></A> example has changed slightly as a
|
||
|
|
result.
|
||
|
|
<LI> The open mode for reading the file of random numbers has been changed from
|
||
|
|
"r" to "rb", for compatibility with non-Unix systems.
|
||
|
|
<LI> <A HREF="mod2sparse.html#copy"><TT>mod2sparse_copy</TT></A> has
|
||
|
|
been fixed so that it copies the <B>lr</B> and <B>pr</B> fields
|
||
|
|
of entries.
|
||
|
|
<LI> The "set -v -e" in the command files for the examples has
|
||
|
|
been replaced by two commands, "set -e" and "set -v", since some
|
||
|
|
shells can't set two options at once.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
A few minor fixes to the documentation have also been made.
|
||
|
|
|
||
|
|
|
||
|
|
<H2>Version of 2001-05-04.</H2>
|
||
|
|
|
||
|
|
Changes and new features regarding programs and associated
|
||
|
|
documentation and examples:
|
||
|
|
<OL>
|
||
|
|
<LI> Warnings have been added to the documentation about the dangers of
|
||
|
|
using zero codewords for testing (due to the possibility of the decoder
|
||
|
|
accidently being non-symmetric). The examples have been changed to
|
||
|
|
not use zero codewords, except for
|
||
|
|
<A HREF="ex-ham7a"><TT>ex-ham7a</TT></A>, which still
|
||
|
|
demonstrates this facility.
|
||
|
|
<LI> Decoding by probability propagation has been changed so that if
|
||
|
|
a probability ratio gets set to NaN ("not a number", the result of
|
||
|
|
infinite but conflicting evidence from different sources), the probability
|
||
|
|
ratio is changed to 1, in hopes that something sensible may result.
|
||
|
|
<LI> The decoding procedures have been changed to decode a bit to a 1 if
|
||
|
|
there is a tie, so that any resulting asymmetry in decoding will
|
||
|
|
make zero decoding less, rather than more, likely. See point (1) above.
|
||
|
|
<LI> All programs now allow a file name argument to be "-", which specifies
|
||
|
|
standard input or standard output, as appropriate. The
|
||
|
|
<A HREF="ex-ldpc36-5000a"><TT>ex-ldpc36-5000a</TT></A> example has been
|
||
|
|
changed to use this facility in order to avoid creating lots of files.
|
||
|
|
<LI> Channels with noise from a logistic distribution (AWLN) have been
|
||
|
|
implemented. For details,
|
||
|
|
see the <A HREF="channel.html">channel documentation</A>.
|
||
|
|
<LI> The <B>make-gen</B> program for "dense" or "mixed" options was modified
|
||
|
|
so that when some parity checks are redundant, others are not declared
|
||
|
|
redundant when they aren't. This makes the result compatible with
|
||
|
|
what is obtained with the "sparse" option. The example in the
|
||
|
|
<A HREF="dep-H.html">discussion of linear dependence in parity check
|
||
|
|
matrices</A> has changed slightly as a result.
|
||
|
|
<LI> The messages displayed by the <A HREF="decoding.html#decode">decode</A>
|
||
|
|
program have changed slightly: The block size is no longer displayed,
|
||
|
|
and the percentage of bits changed is now shown. The data output
|
||
|
|
when the <B>-t</B> option is specified now includes the number of
|
||
|
|
bits changed in each block.
|
||
|
|
<LI> A new <B>-T</B> option to <A HREF="decoding.html#decode">decode</A>
|
||
|
|
for displaying
|
||
|
|
<A HREF="decode-detail.html">detailed information on decoding</A>
|
||
|
|
has been added.
|
||
|
|
<LI> Doing a <B>make clean</B> will now remove the files created
|
||
|
|
by running the <A HREF="examples.html">examples</A>.
|
||
|
|
<LI> The files created by the <A HREF="examples.html">examples</A> now
|
||
|
|
start with "<TT>ex-</TT>" and contain a ".", to make them easier to
|
||
|
|
identify for cleanup, and the saved output file now ends in
|
||
|
|
"<TT>-out</TT>" rather than "<TT>.out</TT>".
|
||
|
|
<LI> The scripts for the examples now use the <B>-v</B> option of <B>set</B>
|
||
|
|
rather than <B>-x</B>, so that the command lines are echoed
|
||
|
|
faithfully as they are read.
|
||
|
|
<LI> Two new <A HREF="examples.html">examples</A> have been added:
|
||
|
|
<TT>ex-dep</TT> demonstrates what happens when parity check matrices
|
||
|
|
have redundant row, and <TT>ex-wrong-model</TT> investigates what
|
||
|
|
happens when the wrong model is used to decode.
|
||
|
|
</OL>
|
||
|
|
Changes and new features regarding program modules and other internals:
|
||
|
|
<OL>
|
||
|
|
<LI> Instructions have been added on
|
||
|
|
<A HREF="modify.html">how to modify the programs</A>, and some
|
||
|
|
code has been reorganized to facilitate modifications.
|
||
|
|
<LI> The makefile has been made trivial, simply recompiling everything
|
||
|
|
from scratch every time. This is simpler and less error prone
|
||
|
|
than putting in dependencies.
|
||
|
|
Compiling all the programs takes only about five seconds on a
|
||
|
|
modern PC.
|
||
|
|
<LI> The
|
||
|
|
<A HREF="mod2dense.html#invert_selected"><TT>mod2dense_invert_selected</TT></A>
|
||
|
|
procedure has been changed
|
||
|
|
to take an additional argument in which a permutation of rows is
|
||
|
|
returned. This extension is needed in order for the result when
|
||
|
|
the matrix is not of full rank to include as many rows as possible,
|
||
|
|
as needed for the above modification of <B>make-gen</B>.
|
||
|
|
<LI> New routines
|
||
|
|
<A HREF="mod2dense.html#copyrows"><TT>mod2dense_copyrows</TT></A> and
|
||
|
|
<A HREF="mod2sparse.html#copyrows"><TT>mod2sparse_copyrows</TT></A> have
|
||
|
|
been added, analogous to the previous routines for copying columns.
|
||
|
|
<LI> The decoding procedures have been changed to always return the bit
|
||
|
|
probabilities (previously, one could pass a null pointer to suppress
|
||
|
|
this). This makes things simpler, and facilitates the production of
|
||
|
|
detailed trace output when the <B>-T</B> option is used.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
The following bugs were fixed:
|
||
|
|
<OL>
|
||
|
|
<LI> A problem with <B>print-gen</B> prevented the <B>-d</B> option from working
|
||
|
|
in most cases. The documentation was also fixed to note what
|
||
|
|
the <B>L</B> and <B>U</B> matrices printed will look like.
|
||
|
|
<LI> The documentation for
|
||
|
|
<A HREF="mod2sparse.html#copycols"><TT>mod2sparse_copycols</TT></A> and
|
||
|
|
<A HREF="mod2dense.html#copycols"><TT>mod2dense_copycols</TT></A>
|
||
|
|
was ambiguous. It has been clarified. The dense and sparse
|
||
|
|
implementations were inconsistent. The sparse version has been changed
|
||
|
|
to match the dense version, which was and is the only version actually
|
||
|
|
used in the LDPC software.
|
||
|
|
<LI> In <TT>decode.c</TT>, a variable declared to be <TT>float</TT> was printed
|
||
|
|
using "<TT>%f</TT>", which strangely didn't work with one compiler.
|
||
|
|
It's now declared as <TT>double</TT>.
|
||
|
|
</OL>
|
||
|
|
|
||
|
|
There were also numerous minor cleanups of program code and documentation.
|
||
|
|
|
||
|
|
<H2>Version of 2000-03-19.</H2>
|
||
|
|
|
||
|
|
This was the first public release.
|
||
|
|
|
||
|
|
<HR>
|
||
|
|
|
||
|
|
<A HREF="index.html">Back to index for LDPC software</A>
|
||
|
|
|
||
|
|
</BODY></HTML>
|