Frobby Version 0.8.1 Available

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Bjarke Hammersholt Roune

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Jul 7, 2009, 12:09:41 AM7/7/09
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*** Version 0.8.2, 2009-07-07

New features and improvements in this version include

- Fast dimension and codimension of monomial ideals
- Various speed improvements (see below)
- Generation of random edge ideals
- Optimization over maximal standard monomials with negative
objective function.

The new (co)dimension code uses an algorithm gleaned from the source
code of Macaulay 2, though the code in Frobby is substantially faster
due to a few improvements. It is not known to me who to credit with
this algorithm. Now that Frobby supports negative objective functions,
the more general optimize action can also be used to compute the
dimension, but this is not nearly as fast.

There are also many smaller improvements. They are too many to list
here, but the more visible ones are shown below.

** Performance improvements

- Actions frobgrob and optimize are substantially faster due to code
improvements and due to the bound optimization now being
accessible. It had been turned off by mistake in the previous
release, even when explicitly requested via the command line option
-bound. The bound optimization itself has been improved to work
with objective funtions with negative entries.

- Improved the pure power split selection strategies to choose a
middle variable in case of ties instead of the left-most
variable. This makes no difference for most inputs, but leads to
dramatic speed-ups for some particular highly non-generic inputs.

- All slice-based algorithms are slightly faster due to low-level
code improvements.

- The action optimize now uses the degree split strategy by default
instead of median, which is faster.

** Deprecated functionality

- The action frobgrob is deprecated and will be removed in a future
version of Frobby. Use the action optimize with options
chopFirstAndSubtract and maxStandard to achieve the same effect.

- The split selection strategy named frob is now deprecated and will
be removed in a future version of Frobby. Use the name degree to
achieve the same effect.

** Miscellaneous improvements

- The polynomial ring is named R in the Macaulay 2 format, which is a
problem if there is also a variable named R in the ring, since then
Macaulay 2 will report an error on reading the file. Frobby now
renames the ring to R1 in that case, or R2 if there is also a
variable named R1 and so on.

- All formats now support underscores as part of variable names.

- There is now an output format "count" that just prints the total
number of generators.

** Technical Improvements

- A benchmark suite has been added to detect preformance regressions,
such as the above situation with the bound optimization getting
turned off. There is also support for profiling to detect the lines
of code that are taking the most time.

- The amount of information in the developer documentation, which is
generated based on source code comments, has increased
substantially.

- The design for how internal C++ tests are done is much improved and
the number of tests bas been expanded substantially.

- Code file dependency tracking is much improved. It is now fully
automatic,
so the Makefile target depend is removed.

- All Frobby files now use unix-style line endings, rather than the
mix that was there before.

- Frobby now explicitly refuses to use independence splits when
solving Frobenius problems and other optimization problems. They
were never implemented for that case.

- The install makefile target now uses sudo, so that it does not have
to be run as root to install Frobby. This is not the case on
Cygwin, which does not seem to have sudo.

- Option -chopFirstAndSubtract now fails gracefully when there are no
variables, such as when using -iformat null. In general actions now
deal well with -iformat null, and this is now part of the
testsuite.

- Numerous small improvements to performance, design and comments all
over the codebase.
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