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[ginac.git] / NEWS

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 This file records noteworthy changes.
 
-0.8.1 (15 April 2001)
+0.8.4 (<date>)
+* 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".
+* New functions/methods:
+   - canonicalize_clifford() (helpful when comparing expressions containing
+     Dirac matrices)
+   - symmetrize() and antisymmetrize()
+   - numer_denom() (return numerator and denominator)
+   - map() (apply function to subexpressions)
+   - evalm() (evaluate sums and products 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.
+* Fixed possible crash when calling subs() on expressions with non-commutative
+  products.
+* Positive integer powers of non-commutative expressions are automatically
+  expanded.
+
+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