degree(), ldegree(), coeff(), lcoeff(), tcoeff() and collect() can now

[ginac.git] / NEWS

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 This file records noteworthy changes.
 
+0.8.1 (<date>)
+* degree(), ldegree(), coeff(), lcoeff(), tcoeff() and collect() can now
+  be used with constants and indexed expressions as well, so you can use
+  it to collect by powers of Pi or find the coefficient of gamma~0.
+  Limitations:
+   - it only works with symbols, constants 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 the functions on elements of noncommutative products might
+     return wrong or surprising results
+* Added preliminary (re)implementations of color and clifford classes.
+* simplify_indexed(): contraction of symmetric and antisymmetric tensors
+  is zero.
+* Some bugfixes (indexed objects, archive writing).
+
 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