* irem(), iquo(): throw an exception, when second argument vanishes.

[ginac.git] / NEWS

This file records noteworthy changes.

1.0.11 (18 September 2002)
* Fixed a possible memory corruption in contractions of indexed objects with
  delta or metric tensors.
* Computing the derivative of a power series object with respect to a symbol
  that is not the expansion variable now works correctly.
* Several bugfixes in code generation.

1.0.10 (24 July 2002)
* Powers of indexed objects are now parenthesized correctly in LaTeX output.
* Input parser handles indices (they have to be specified in the same list
  as the symbols).
* Added some limited support for subspaces in the idx and tensor classes.
* Fixed a bug in canonicalize() (antisymmetric canonicalization of an already
  sorted list containing two or more equal objects failed to return 0).

1.0.9 (11 June 2002)
* simplify_indexed() now raises/lowers dummy indices to canonicalize the index
  variance. This allows some simplifications that weren't possible before,
  like eps~a.b~c~d*X.a*X~b -> 0 and X.a~a-X~a.a -> 0.
* Implemented relational::subs().
* Fixed bug in simplify_ncmul() for clifford objects.

1.0.8 (31 March 2002)
* Improvements in memory usage of the expand() methods.

1.0.7 (18 March 2002)
* Fixed LaTeX output of indexed and matrix objects.
* Fixed matrix::pow(n) for n==0 and added helper functions to create unit
  matrices "ex unit_matrix(unsigned, unsigned)".

1.0.6 (4 March 2002)
* "(x+1).subs(x==x-1)" now returns the correct result "x" instead of "x-1".

1.0.5 (27 January 2002)
* (l)degree(s), coeff(s, n) and collect(s) were extended to accept expressions
  of any class (except add/mul/ncmul/numeric) for "s". They should even work
  if "s" is a "power" object, as long as the exponent is non-integer, but with
  some limitations. For example, you can "collect(a*2^x+b*2^x, 2^x)" to get
  "(a+b)*2^x", but "degree(2^(3*x), 2^x)" yields 0 instead of 3).
* Fixed a small output bug.

1.0.4 (24 January 2002)
* Speedup in expand().
* Faster Bernoulli numbers (Markus Nullmeier).
* Some minor bugfixes and documentation updates.

1.0.3 (21 December 2001)
* Fixed a bug where quo() would call vector::reserve() with a negative
  argument.
* Fix several bugs in code generation.

1.0.2 (19 December 2001)
* Input parser recognizes "sqrt()", which is also used in the output.
* divide(a,b,q) only modifies q if the division succeeds; also, divide(a,b,a)
  works now.
* Fixed small bug in dummy index renaming which could cause it to not
  recognize renamable indices in some cases.
* power::degree() and power::ldegree() throw an exception when encountering
  a non-integer exponent.
* Add output-support for Python bindings.

1.0.1 (22 November 2001)
* Function sqrfree() handles a few more cases now.
* Class relational has real canonical ordering now.
* Handle obscene libreadline version numbers when building ginsh.

1.0.0 (6 November 2001)
* Some internal reorganization resulting in a general speed-up.
* The last 3 evaluated expressions in ginsh are now referred to with the
  tokens '%', '%%' and '%%%'. The old '"', '""' and '"""' remain for
  compatibility but may be removed in a future version of GiNaC.

0.9.4 (20 September 2001)
* Functions have better support for external scripting languages.
* Interface cleanups and bugfixes.
* Fix silly bug in evalf() that prevented things like 2^Pi being computed.

0.9.3 (16 August 2001)
* series expansion now much more consistent for small order expansion.
* lsolve() accepts algorithmic hint as parameter.

0.9.2 (31 July 2001)
* Epsilon tensor is more functional.
* simplify_indexed() is better at detecting expressions that vanish for
  symmetry reasons.
* Several little bugfixes and consistency enhancements.

0.9.1 (27 June 2001)
* Ctors of class numeric are not explicit any more.  All built-in callers for
  pseudofunctions are now templated and default to ex arguments which relaxes
  the need for explicit ctors.
* New functions/methods:
   - find()
   - remove_first(), remove_last(), sort() and unique() for lists
   - symmetrize_cyclic()
   - decomp_rational()
* Instead of just totally symmetric or antisymmetric, complex symmetries
  can now be defined for indexed objects. Symmetries are described by a
  tree of "symmetry" objects that is constructed with the sy_none(),
  sy_symm(), sy_anti() and sy_cycl() functions. The symmetry of a function
  with respect to its arguments can also be defined (this is currently
  only used for the Beta function).
* Generalized map() to take a function object instead of a function pointer.
  This allows passing an arbitrary number of additional state to the
  function being called.
* color_trace(), dirac_trace(), diff(), expand(), evalf() and normal() work
  better with container classes, e.g. using color_trace() on a relation will
  take the trace on both sides, using diff() on a matrix differentiates every
  element etc.
* diff() works properly with non-commutative products and indexed objects.
* New option flag "expand_function_args" for expand().
* Supplement some (now deprecated) macros by inlined template functions:
  - is_of_type(foo, type) -> is_a<type>(foo)
  - is_ex_of_type(foo, type) -> is_a<type>(foo)
  - is_exaclty_of_type(foo, type) -> is_exaclty_a<type>(foo)
  - is_ex_exaclty_of_type(foo, type) -> is_exaclty_a<type>(foo)
  - ex_to_foobar(baz)  ->  ex_to<foobar>(baz)
* rem(c, p[x], x) (c: numeric, p[x]: polynomial) erroneously returned p[x]
  instead of c.
* Small bugfixes in pattern matching.
* Updated libtool to version 1.4.

0.9.0 (7 June 2001)
* In the output and in ginsh, lists are now delimited by { } braces, and
  matrices are delimited by single [ ] brackets.
* simplify_indexed() renames dummy indices so, e.g., "a.i*a.i+a.j*a.j" gets
  simplified to "2*a.i*a.i" (or "2*a.j*a.j").
* New functions/methods:
   - canonicalize_clifford() (helpful when comparing expressions containing
     Dirac matrices)
   - symmetrize() and antisymmetrize()
   - numer_denom() (return numerator and denominator in one call)
   - map() (apply function to subexpressions)
   - evalm() (evaluate sums, products and integer powers of matrices)
* Added a new function match() for performing pattern matching. subs() and
  has() also accept patterns as arguments. A pattern can be any expression,
  optionally containing wildcard objects. These are constructed with the
  call "wild(<unsigned>)" and are denoted as "$0", "$1" etc. in the output
  and in ginsh.
* Positive integer powers of non-commutative expressions (except matrices)
  are automatically expanded.
* Removed cint subdirectory, ginaccint is a separate package now due to 
  packaging considerations.
* Several little bugfixes.

0.8.3 (11 May 2001)
* color and clifford classes are functional and documented.
* New "spinidx" class for dotted/undotted indices.
* Predefined spinor metric tensor (created by spinor_metric()).
* Symbols can have a LaTeX name, e.g. symbol s("s", "\\sigma");
* LaTeX output of indexed objects is much nicer.
* Fixed some build problems (with recent libreadline).
* Semantics of arithmetic operators now follows the C++ rules more strictly.

0.8.2 (24 April 2001)
* degree(), ldegree(), coeff(), lcoeff(), tcoeff() and collect() work with
  non-symbols as the second argument in ginsh.
* the argument to collect() can be a list of objects in which case the
  result is either a recursively collected polynomial, or a polynomial in
  a distributed form with terms like coeff*x1^e1*...*xn^en, as specified by
  the second argument to collect().
* Several bugfixes (including a nasty memory leak in .normal()).
* class matrix: solve() doesn't call algorithms redundantly any more and
  inverse() falls back to solve() which works in more general cases.

0.8.1 (16 April 2001)
* degree(), ldegree(), coeff(), lcoeff(), tcoeff() and collect() can now
  be used with constants, functions and indexed expressions as well, so you
  can use it to collect by powers of Pi or sin(x), or to find the coefficient
  of gamma~0.
  Limitations:
   - it only works with symbols, constants, functions and indexed expressions,
     trying to find the coefficient of, e.g., "x^2" or "x+y" won't work;
   - it does not know about dummy index summations; the coefficient of
     gamma~0 in p.mu*gamma~mu should be p.0 but is returned as 0;
   - using coeff(), tcoeff(), lcoeff() or collect() on elements of
     noncommutative products might return wrong or surprising results.
* subs() no longer only substitutes symbols and indices but performs a more
  general "syntactic substitution", i.e. it substitutes whole objects in sub-
  expressions. You can subs((a+b)^2,a+b==3) and get 9, but subs(a+b+c,a+b==3)
  doesn't do anything.
  Limitations:
   - substituting numerics (subs(expr, 2==4)) will not replace then in all
     occurences; in general, you shouldn't substitute numerics, though.
* Added preliminary (re)implementations of color and clifford classes.
* simplify_indexed(): contraction of symmetric and antisymmetric tensors
  is zero.
* Replaced the various print*() member functions by a single print() that
  takes a print_context object that determines the output formatting. This
  should make it easier to add more output types, such as LaTeX output,
  which is based on work by Stefan Weinzierl.
* Added functions to retrieve the properties stored in archive objects
  outside of unarchive() (for printing or debugging purposes).
* Some bugfixes (indexed objects, archive writing).
* .collect() on non-polynomials is now algebraically correct.

0.8.0 (24 March 2001)
* Complete revamp of indexed objects. Instead of multiple classes for
  indexed things and their indices there is now only one "indexed" class
  and two types of indices: "idx" for simple indices and "varidx" for
  indices with variance. There are predefined delta, epsilon and metric
  tensors, and a function simplify_indexed() that performs canonicalization
  and dummy index summations. Matrix objects can be indexed for doing simple
  linear algebra.
* Added an option "expand_indexed" to expand() to perform expansion of
  indexed objects like (a+b).i -> a.i + b.i
* Renamed get_indices() to get_free_indices(), which no longer returns
  dummy indices and checks the consistency of indices in sums.
* sqrfree() factorization fixed and improved syntactically.
* subs() works on matrices.
* Matrices can be constructed from flat list of elements; diagonal matrices
  can be constructed from list of diagonal elements with diag_matrix().
* Fixed memory leak in expand().
* Operator% for objects of class ncmul has gone.  Use operator* now for that
  case too, which is much more natural.

0.7.3 (28 February 2001)
* Several bugfixes and minor performance tunings.
* Added a section to the tutorial about adding new algebraic classes to GiNaC.
* Closed many in-source documentation gaps.

0.7.2 (17 February 2001)
* Several bugfixes in power series expansion, one of them critical.

0.7.1 (7 February 2001)
* Fix problems with Cint that were caused by CLN's overloaded operator new.
* Fix compilation errors with GCC3.
* normal() handles large sums of fractions better and normalizes the exponent
  of power expressions.
* expand() always expands the exponent and transforms x^(a+b) -> x^a*x^b.
* Some bugfixes of series expansion around branch cuts of special functions.

0.7.0 (15 December 2000)
* Requires CLN 1.1 now.  Class numeric doesn't use an indirect pointer to the
  actual representation any more.  This is a speedup.
* mul::expand() was reengineered to not allocate excess temporary memory.
* Non-integer powers of a symbol are treated as constants by (l)degree() and
  coeff().  Using these functions on an expression containing such powers used
  to fail with an internal error message.  The side-effect is that collect()
  can be used on expressions which are not polynomials.
* Added a man page for the ginac-config script.
* Ctor of numeric from char* honors Digits.

0.6.4 (10 August 2000)
* Complete revamp of methods in class matrix.  Some redundant (and poor)
  implementations of elimination schemes were thrown out.  The code is now
  highly orthogonal, more flexible and much more efficient.
* Some long standing and quite nasty bugs were discovered and fixed in the
  following functions: add::normal(), heur_gcd(), sr_gcd() and Order_eval().

0.6.3 (25 July 2000)
* Derivatives are now assembled in a slightly different manner (i.e. they
  might 'look' different on first sight).  Under certain circumstances this
  can result in a dramatic speedup because it gives hashing a better chance,
  especially when computing higher derivatives.
* Some series expansions of built-in functions have been reengineered.
* The algorithm for computing determinants can be chosen by the user.  See
  ginac/flags.h and ginac/matrix.h.
* The Dilogarithm (Li2) now has floating point evaluation, derivative and a
  proper series expansion.
* Namespace 'std' cleanly disentangled, as demanded by ISO/EIC 14882-1998(E).
* Some minor bugfixes, one major lsolve()-bugfix and documentation updates.

0.6.2 (21 June 2000)
* ginaccint.bin is now launched by a binary program instead of by a scripts.
  This allows us to write #!-scripts.  A small test suite for GiNaC-cint was
  added.
* Several minor bugfixes.

0.6.1 (18 May 2000)
* Cleanup in the interface to Cint.  The required version is now Cint 5.14.38.
* Several bugfixes in target install.

0.6.0 (11 May 2000)
* IMPORTANT: Several interface changes make programs written with GiNaC 
  much clearer but break compatibility with older versions:
  - f(x).series(x,p[,o]) -> f(x).series(x==p,o)
  - series(f(x),x,p[,o]) -> series(f(x),x==p,o)
  - gamma() -> tgamma()  (The true Gamma function, there is now also
    log(tgamma()), called lgamma(), in accord with ISO/IEC 9899:1999.)
  - EulerGamma -> Euler
* #include'ing ginac.h defines the preprocessor symbols GINACLIB_MAJOR_VERSION,
  GINACLIB_MINOR_VERSION, and GINACLIB_MICRO_VERSION with the respective GiNaC
  library version numbers.
* Expressions can be constructed from strings like this:
    ex e("2*x+y", lst(x, y));
* ex::to_rational() provides a way to extend the domain of functions like
  gcd() and divide() that only work on polynomials or rational functions (the
  good old ex::subs() method reverses this process)
* Calling diff() on a function that has no derivative defined returns the
  inert derivative function "Derivative".
* Several new timings in the check target.  Some of them may be rather rude 
  at your machine, feel free to interrupt them.

0.5.4 (15 March 2000)
* Some algorithms in class matrix (notably determinant) were replaced by
  less brain-dead ones and should now have much better performance.
* Checks were completely reorganized and split up into three parts:
  a) exams (small regression tests with predefined input)
  b) checks (lenghty coherence checks with random input)
  c) timings (for coherence and crude benchmarking)
* Behaviour of .evalf() was changed: it doesn't .evalf() any exponents.
* Expanded expressions now remember they are expanded to prevent
  superfluous expansions.
* Small bugfixes and improvements in the series expansion.

0.5.3 (23 February 2000)
* A more flexible scheme for registering functions was implemented,
  allowing for remembering, too.
* Some Bugfixes.

0.5.2 (16 February 2000)
* Mainly fixes a bug in the packaging of release 0.5.1.

0.5.1 (14 February 2000)
* Fixes a small number of bugs.

0.5.0 (7 February 2000)
* Expressions can be written ("archived") to files and read therefrom.
* Addition of GiNaC-cint, which lets you write complete programs in
  an interactive shell-like manner in your favoured programming
  language (i.e. C++).

0.4.1 (13 December 1999)
* Series Expansion of Gamma function and some other trigonometric
  functions at their poles works now.
* Many more evaluations of special functions at points where
  exact results exist.
* info_flags::rational doesn't return true for complex extensions
  any more---use info_flags::crational for the old behaviour.
  info_flags::integer and -::cinteger work similarly, the same
  holds for types like info_flags::rational_polynomial.

0.4.0 (26 November 1999)
* First public release.