> < ^ Date: Mon, 24 Jun 2002 13:39:17 +0100
> < ^ From: Steve Linton <sal@dcs.st-and.ac.uk >
^ Subject: Bugfix 1 for GAP 4 revsion 3

Dear GAP Forum,

This is to announce bugfix number 1 for GAP 4.3. The priority of this fix
is high.

You should not apply this fix to any version of GAP before GAP
4.3. (If you run such an old version, please update to GAP 4.3 (and
this bugfix) as release 4.3 corrects many problems.)

This fix corrects:

1) A bug in the handling of Processes with empty input or output streams.
2) An error in the function for computing quotients of algebra modules.
3) An error in computing the strongly connected components of a binary
relation in which incorrect results can be returned.
4) A "no method found" error in OrbitStabilizerAlgorithm for infinite
5) Calculation of iterated automorphism groups might stop with an error message.
6) A segmentation fault when converting length 0 compressed vectors to
larger fields
7) The output of the internal pager (see 'Pager') is no longer copied to
log files.
8) Some memory is not freed up as soon as it could be, resulting in
over-use of memory and over-large saved workspaces
9) Saving and loading a workspace using a kernel containing a
statically loaded user module (most likely a compiled GAP file)
did not work.
10) Problems with EulerianFunction for certain types of groups

XXXX error descriptions
Errors 1), 2), 4), 5) and 9) may cause unjustified errors
Error 6) causes GAP to crash
Errors 7) and 8) are just nuisances
Errors 3) and 10) may give incorrect results without warning.

Many thanks to:

Frank Heckenbach for reporting error 1
Manuel Delgado for reporting error 3
Walter Becker for reporting problem 5
Peter Mueller for reporting error 6
Juergen Mueller for reporting errors 8 and 9
Noam Katz for reporting error 10

Installing the bugfix.

Load the zoo archive `fix4r3n1.zoo' from the bugfixes web page
http://www-gap.dcs.st-and.ac.uk/~gap/Info4/bugfixes.html Alternatively
you can find this file in the `bugfixes' directory of the GAP4 ftp

Unpack the file in the home directory of your GAP distribution (the
directory containing the `lib' and `grp' directories) using `unzoo -x
fix4r3n1.zoo'. `unzoo' may ask you for permissions to overwrite files,
answer this with Y)es or A)ll. This will replace the erroneous files by
fixed versions.

(On a PC or a Mac you will have to copy `unzoo' in the same directory and
enter the argument line after the call to `unzoo'.)
Make sure you have write permissions when applying the fix.

The fix is also available in the alternative .zip and .tar.gz
formats. The .zip format is intended mainly for Windows users (and
uses Windows line-ending conventions) the .tar.gz format in intened
mainly for UNIX users and uses UNIX line-ending conventions (the .zoo
format is usable on any system). If you wish to use one of these, you
should unpack it in the GAP root directory, overwriting files as
necessary, as described for the .zoo version above.

This fix changes the kernel. You have to recompile by calling `make' in the
directory in which you unpacked the fix.

Windows users can find a new binary in the file `wbin4r3n1.zoo' in the
`bugfixes' directory: Extract this archive in the same place as the fix
archive to get a new `bin/gapw95.exe' file.

Macintosh users should download the file 'bin4r3n1-PPC.sit' (for PPC
machines) or 'bin4r3n1-68k.sit' (for 68k machines), from the 'bugfixes'

You can remove the file `description1' afterwards.

This fix invalidates any workspaces saved before applying the fix.
They will most likely not load successfully into the fixed system,
and will almost certainly not work even if they do load correctly.

After installing the bugfix you can test whether
the bugfix has been applied correctly by starting GAP from the `gap4r3'
directory with the -x 80 command-line option and issuing

gap> ReadTest("tst/bugfix.tst");
+ bugfixes test
+ GAP4stones: 163

(The output should be like this if the bugfixes have been installed
correctly. The number of GAP4stones may vary according to your system.)

Running this test is not a necessary part of installing a bug fix, but only
serves as a confirmation that everything went well. The test might run for
a long time and GAP will not output information while running. Note that it
is not possible to run the test twice without restarting GAP and that an
interruption of the test with CTRL-C will produce lots of (harmless) error

Steve Linton    June 2002

Steve Linton	School of Computer Science  &
      Centre for Interdisciplinary Research in Computational Algebra
	     University of St Andrews 	 Tel   +44 (1334) 463269
http://www-theory.dcs.st-and.ac.uk/~sal	 Fax   +44 (1334) 463278   

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