[GAP Forum] Bugfix 4 for GAP 4.4

[Steve Linton]

Dear Forum,

This is to announce a bugfix that updates GAP 4.4.3 to GAP 4.4.4 .
The priority of this fix is high. The bugfix is already on the GAP FTP site, as
are gap4r4p4 archives incorporating the fix. The GAP website will be adjusted
to refer to this fix and these archives very shortly.

You should not apply this fix to any version of GAP before GAP 4.4. (If you
run such an old version, please update to GAP 4.4 as release 4.4 corrects
many problems.)
GAP Bugfixes now are comprehensive. If you forgot to install prior bugfixes,
you do only need to install this, and no prior ones. If you did not yet
install GAP 4.4 you only need to install GAP 4.4.3 which will incorporate
this bugfix.

This fix corrects:

1) A problem with the function `SuggestUpdates' to check for the most recent
   version of packages available
2) A problem that caused `MatrixOfAction' to produce an error when
   the algebra module was constructed as a direct sum.
3) An error in the `Order' method for matrices over cyclotomic fields
   which caused this method to return `infinity' for matrices of finite
   order in certain cases.
4) Representations computed by `IrreducibleRepresentations' in
   characteristic 0 erraneously claimed to be faithful.
5) Problems with computing n-th power maps of character tables,
   where n is negative and the table does not yet store its irreducible
   characters.
6) A primitive representation of degree 574 for PSL(2,41) has been missing
   in the classification on which the GAP library was built.
7) Element conjugacy in large-base permutation groups sometimes was
   unnecessarily inefficient.
8) A bug in 'Append' for compressed vectors over GF(2), if the length
   of the result is 1 mod 32 (or 64) the last entry was forgotten to copy.
9) A problem with the Ree group Ree(3) of size 1512 claiming to be
   simple.
10) An error in the membership test (`in') for groups `GU(n,q)' and
    `SU(n,q)' for non-prime `q'.
11) A missing method for getting the letter representation of an associate
   word in straight line program representation.
12) A problem with the construction of vector space bases where the given
    list of basis vectors is itself an object that was returned by `Basis'.
13) An error in the kernel code for ranges which caused `-1 in [1..2]' to
    return `true', e.g.
14) An error recording Boolean lists in saved workspaces.
15) A problem of `AbelianInvariantsMultiplier' insisting that a result of
    `IsomorphismFpGroup' is known to be surjective.
16) A problem in the selection function for primitive and transitive groups
    if no degree is given.
17) An error in the routien for `Resultant' if one of the polynomials has
    degree zero.
18) `ReducedConfluentRewritingSystem' returning a cached result that might
    not conform to the ordering specified.


Errors 1, 2, 5, 11, 12, 15 and 17 may cause GAP to stop with an error
message.  Errors 3, 4, 6, 8, 9, 10, 13, 14, 16 and 18 may cause GAP to
return wrong results without a warning.

Many thanks to Jan Draisma for reporting error 2, to Simon Nickerson
for reporting errors 3 and 10 and to Jack Schmidt for reporting error
9 to Sebastian Freudt for reporting error 10, to Laurent Bartholdi for
reporting error 12 and to Anvita for reporting error 13, 
to Alex Makosi for reporting error 14, Sebastian Dany for
reporting error 15, Ignat Soroko for reporting errors 16 and 17, Isabel
Araujo for reporting error 18.

This bugfix also incorporates prior fixes to GAP 4.4, which are listed at
the web page:
http://www.gap-system.org/tmpsite/Download/bugs.html

     Installing the bugfix.
     ======================

Load the zoo archive `fix4r4p4.zoo' (or respectively other formats) from the
bugfixes web page http://www.gap-system.org/tmpsite/Download/upgrade.html

Alternatively you can find this file in the `bugfixes' directory of the GAP4
ftp distribution.

Unpack the file in the home directory of your GAP distribution (the
directory containing the `lib' and `grp' directories), for example by
using `unzoo -x fix4r4p4.zoo' if you use the `zoo' archive.
The archive uncompressor program 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.

(Under Windows or MacOS 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.

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

Windows users will find a new binary as `bin/gapw95.exe' in the archive.

MacOS users must use the `zoo' archive and will find a new binary
in the root directory.


After installing the bugfix you can test whether the bugfix has been applied
correctly by starting GAP from the `gap4r4' directory and issuing

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

(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
messages.


	With best wishes for the New Year


	Steve Linton for the GAP Group
	December 2004


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