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[ginac.git] / NEWS

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 This file records noteworthy changes.
 
+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.