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  Release 4.4.5 (May 2005)

  Fixed bugs

   1. GroupWithGenerators returned a meaningless group object
      instead of signaling an error when it was called with an
      empty list of generators.
   2. A rare problem with the choice of prime in the
      Dixon-Schneider Algorithm for computing the character
      table of a group. [Reported by Jack Schmidt]
   3. DirectProduct for trivial permutation groups returned a
      strange object.
   4. When computing preimages under an embedding into a direct
      product of permutation groups, if the element was not in
      the image of the embedding then a permutation had been
      returned instead of fail.
   5. A problem with PolynomialReduction running into an
      infinite loop.
   6. Adding linear mappings with different image domains was
      not possible. [Reported by Pasha Zusmanovich]
   7. Multiplying group ring elements with rationals was not
      possible. [Reported by Laurent Bartholdi]
   8. Random now works for finite fields of size larger than 2^
      28. [Reported by Jack Schmidt]
   9. Two problems with PowerMod for polynomials. [Reported by
      Jack Schmidt]
  10. Univariate polynomial creators did modify the coefficient
      list passed. [Reported by Juergen Mueller]
  11. Some methods for computing the sum of ideals returned the
      first summand instead of the sum. [Reported by Alexander
      Konovalov]
  12. Some code and comments in the GAP kernel assumed that
      there is no garbage collection during the core printing
      function Pr, which is not correct. This could cause GAP in
      rare cases to crash during printing permutations,
      cyclotomics or strings with zero bytes. [Reported by
      Warwick Harvey]
  13. Fixed IntHexString to accept arguments not in IsStringRep;
      the argument is now first converted if necessary.
      [Reported by Kenn Heinrich]
  14. Wrong result in Intersection for PC groups.
  15. The function CompareVersionNumbers erroneously ignored
      leading non-digit characters.
      A new feature in the corrected version is an optional
      third argument "equal", which causes the function to
      return true only if the first two arguments describe equal
      version numbers; documentation is available in the
      ext-manual. This new feature is used in LoadPackage, now
      one can require a specific version of a package.
      The library code still contained parts of the handling of
      completion files for packages, which does not work and
      therefore had already been removed from the documentation.
      This code has now been removed.
      Now a new component PreloadFile is supported in 
      PackageInfo.g files; if it is bound then the file in
      question is read immediately before the package or its
      documentation is loaded.
  16. The library code for stabilizer chains contained quite
      some explicit references to the identity (). This is
      unfortunate if one works with permutation groups, the
      elements of which are not plain permutations but objects
      which carry additional information like a memory, how they
      were obtained from the group generators. For such cases it
      is much cleaner to use the One(...) operation instead of
      (), such that the library code can be used for a richer
      class of group objects. This fix contains only rather
      trivial changes () to One(...) which were carefully
      checked by me. The tests for permutation groups all run
      without a problem. However, it is relatively difficult to
      provide test code for this particular change, since the
      "improvement" only shows up when one generates new group
      objects. This is for example done in the package recog
      which is in preparation. [Reported by Akos Seress and Max
      Neunhoeffer]
  17. Using {} to select elements of a known inhomogenous dense
      list produced a list that might falsely claim to be known
      inhomogenous, which could lead to a segfault if the list
      typing code tried to mark it homogenous, since the code
      intended to catch such errors also had a bug. [Reported by
      Steve Linton]
  18. The record for the generic iterator construction of
      subspaces domains of non-row spaces was not complete.
  19. The result of String for strings not in IsStringRep that
      occur as list entries or record components was erroneously
      missing the doublequotes around the strings.
  20. This bug causes InducedPcgs(pcgs, H) to return a pcgs
      which is not induced wrt. the parent pcgs of pcgs. This
      may cause unpredictable behaviour, e. g. when
      SiftedPcElement is used subsequently. [Reported by
      Alexander Konovalov]
  21. Fixed a bug in SmallGroupsInformation(512).
  22. PowerModCoeffs with exponent 1 for compressed vectors did
      not reduce (a copy of) the input vector before returning
      it. [Reported by Frank Luebeck]
  23. Sorting a mutable non-plain list (e.g., a compressed
      matrix over fields of order < 257) could potentially
      destroy that object. [Reported by Alexander Hulpke]
  24. When a workspace has been created without packages (-A
      option) and is loaded into a GAP session without packages
      (same option) then an error message is printed.
  25. So far the functions IsPrimeInt and IsProbablyPrimeInt are
      essentially the same except that IsPrimeInt issues an
      additional warning when (non-proven) probable primes are
      considered as primes.
      These warnings now print the probable primes in question
      as well; if a probable prime is used several times then
      the warning is also printed several times; there is no
      longer a warning for some known large primes; the warnings
      can be switched off. See ?Ref: IsPrimeInt for more
      details.
      If we get a reasonable primality test in GAP we will
      change the definition of IsPrimeInt to do a proper test.
  26. Corrected some names of primitive groups in degree 26.
      [Reported by Robert F Bailey]
  27. Under rare circumstances computing the closure of a
      permutation group by a normalizing element could produce a
      corrupt stabilizer chain. (The underlying algorithm uses
      random elements, probability of failure was below 1
      percent) [Reported by Thomas Breuer]

  New or improved functionality

   1. Several changes for ConwayPolynomial:
        + many new pre-computed polynomials
        + put data in several separate files (only read when
          needed)
        + added info on origins of pre-computed polynomials
        + improved performance of ConwayPolynomial and
          IsPrimitivePolynomial for p < 256
        + improved documentation of ConwayPolynomial
        + added and documented new functions
          IsCheapConwayPolynomial and RandomPrimitivePolynomial
   2. Added method for NormalBase for extensions of finite
      fields.
   3. Added more help viewers for the HTML version of the
      documentation (firefox, mozilla, konqueror, w3m, safari).
   4. New function ColorPrompt. (Users of former versions of a
      colorprompt.g file: Now you just need a ColorPrompt(true);
      in your .gaprc file.)
   5. Specialised kernel functions to support GUAVA 2.0. GAP
      will only load GUAVA in version at least 2.002 after this
      update.
   6. Now there is a kernel function CYC_LIST for converting a
      list of rationals into a cyclotomic, without arithmetics
      overhead.
   7. New functions ContinuedFractionExpansionOfRoot and
      ContinuedFractionApproximationOfRoot for computing
      continued fraction expansions and continued fraction
      approximations of real roots of polynomials with integer
      coefficients.
   8. A method for computing structure descriptions for finite
      groups, available via StructureDescription.
   9. This change contains the new, extended version of the
      SmallGroups package. For example, the groups of orders p^
      4, p^5, p^6 for arbitrary primes p, the groups of
      square-free order and the groups of cube-free order at
      most 50000 are included now. For more detailed information
      see the announcement of the extended package.
  10. The function ShowPackageVariables gives an overview of the
      global variables in a package. It is thought as a utility
      for package authors and referees. (It uses the new
      function IsDocumentedVariable.)
  11. The mechanisms for testing GAP has been improved:
        + The information whether a test file belongs to the
          list in tst/testall.g is now stored in the test file
          itself.
        + Some targets for testing have been added to the
          Makefile in the GAP root directory, the output of the
          tests goes to the new directory dev/log.
        + Utility functions for testing are in the new file tst/
          testutil.g. Now the loops over (some or all) files tst
          /*.tst can be performed with a function call, and the
          file tst/testall.g can be created automatically; the
          file tst/testfull.g is now obsolete. The
          remormalization of the scaling factors can now be done
          using a GAP function, so the file tst/renorm.g is
          obsolete.
        + Now the functions START_TEST and STOP_TEST use
          components in GAPInfo instead of own globals, and the
          random number generator is always reset in START_TEST.
        + GAPInfo.SystemInformation now takes two arguments, now
          one can use it easier in the tests.
  12. MultiplicationTable is now an attribute, and the
      construction of a magma, monoid, etc. from multiplication
      tables has been unified.