Revision history for Algorithm-QuineMcCluskey

1.01
     2019-12-03
	- Debug changes only, does not affect the operation of the
	  non-debug code:

	  Smart comments had some obsolete variables that are now
	  changed. The chart() function, used by Smart comments, made
	  use of firstidx(), which was provided by a module that is no
	  longer included. Changed the code in chart() to use the any()
	  function from List::Util instead.
	- Minor correction to README.md.
1.00
     2019-02-10
	- Moved the formatting functions to_boolean() and
	  to_boolean_term() over to Logic::Minimizer. Tie::Cycle is no
	  longer used, and gets removed from the build requirement in
	  Build.PL.
	- README is now README.md.
	- With Logic::Minimizer finally released yesterday, it's time to
	  send this off to CPAN.
     2018-10-06
	- Removed the terms parameter from find_essentials(),
	  covered_least(), and row_dominance(), which we already
	  had in other structures. This shortened the loops and reduced
	  the number of loop structures needed. Another speed-up.
     2018-09-29
	- Replace columns(), a function that rotated the primes
	  hash using grep and any(), with new function transpose(),
	  which does the same thing using hash keys, and which NYTProf
	  says is faster.
     2018-08-30
	- Examining remels() more closely, it became obvious that
	  it was using maskedmatch() as an block argument to indexes()
	  for every single term against every single element three
	  loops deep. Since maskedmatch() has a set-up cost, this
	  seems wasteful. Created a new function maskedmatchindexes(),
	  which sets up the masks before going through the list once.
	- Which means we no longer are using the indexes() function
	  from List::MoreUtils, which is now removed.
     2018-08-29
	- We now use Logic::Minimizer as a base class.
	- Consequently, removed attributes and methods that are
	  now in Logic::Minimizer, and are provided automatically.
	- Use L::M's catch_errors() for attribute validation.
	- Update Build.PL with Logic::Minimizer requirement.
	- And updated the version number everywhere.

0.19
    2019-07-31
	- There was more processing than needed in least_covered() to do
	  what was basically a find-the-minimum loop, plus it was
	  throwing away information that had to be re-created by the
	  next line of code.
	  Consolidated all of that, resulting in fewer hash-of-array
	  manipulations, and changed the return value from the single
	  term to the term plus its covers.
	  This won't result in a significant speed increase, as most
	  terms are already eliminated by the time we reach this code,
	  but it does simplify it and make it more readable.
	- A side-effect of the above is that countels() is no longer
	  needed, and was removed.
	- Also, while I was doing A-B comparisons, the new version of the
	  function was named covered_least(), and it stayed that way.
	- Streamlined remels() some more, and changed it from a function
	  that got called multiple times for each item in a list, to a
	  function that is called once with a list.
	- Moved the next-level-implicant check of version 0.18 outward
	  two loops (some duplicates still popped up as two different
	  terms could bit flip to the same implicant). Moved the push
	  operation of those implicants outward too, using the keys
	  of the hash used in checking for them.
	- Created width=>6 tests in new files 28-solve.t and 29-solve.t.
0.18
    2018-07-10
	- Check for existence of next-level implicant before pushing it
	  on the list. Which means the next loop runs shorter, saving time.
	- Since we only consider Hamming distances of 1 when comparing
	  covers, it doesn't make sense to have a separate Hamming
	  distance function to find the sole difference position. Merged
	  the code of hdist() and diffpos() into new function hammingd1pos(),
	  which lets us skip the list-checking functions. Since this function
	  is embedded four loops deep, this also saves time.
	- Function remels() was checking item by item even in cases where
	  the list items to remove were the entire list. Streamlined that.
	- The Hamming distance change above meant pairwise() isn't needed
	  now, which was the cause of the version requirement change of
	  List::MoreUtils. Put the older version number back in the
	  requirement.
0.17
    2018-06-21
	- Require latest version (0.428) of List::MoreUtils, as there seems
	  to be a crash-worthy side-effect happening with its earlier version
	  and Perl 5.26, as reported by Slaven Rezic.
	- Upped the version req's of Tie::Cycle, namespace::autoclean, and
	  Module::Build while I was at it.
0.16
     2017-02-27
	- The test in 24-solve.t, "A problem with sixteen possible covers",
	  had typos in four of its covers, all involving the term that
	  should have been BC'D' (the D variable was missing its complement
	  symbol).

0.15
     2017-01-31
	- Stupidly didn't upgrade the version number in QuineMcCluskey.pm.
	- Fix tests in 24-solve.t and 27-solve.t that had a typo in their
	  solution sets.
0.14
     2017-01-19
	- Had set the weed-out-expensive-solutions cost at the start of
	  the loop at 2**width, wrongly thinking that that would be the
	  maximum cost. Found a couple cases where that's not true,
	  making solve() return them as "()". Put those cases in a new
	  test file 27-solve.t.
	- Changed the weeding-out code to use an actual cost from the
	  covers array for the starting value.
0.13
     2017-01-5
	- The special cases where all entries are covered (i.e., all 1s or
	  all 0s in the truth table) causes a cover of all dc characters,
	  which returns "()" for solve(). That's a little unhelpful, so
	  check for that and return either a "(1)" or "(0)".
0.12
     2016-10-8
	- In BUILD, limit 'vars' to the number of variables actually needed.
	- With that change, remove array slice of 'vars' in other parts of
	  the code.
	- Add an 'order_by' attribute (undocumented for now) for use in
	  to_boolean().
	- Removed an unnecessary loop in to_boolean().
	- Corrected the sorting in the get_covers() example.
	- Update comments and Smart Comments.

0.11
     2016-8-25
	- Add method all_solutions(). Update the POD concerning using
	  get_covers() to refer to all_solutions().
0.10
     2016-7-20
	- Check to see if the terms (minterms, maxterms, or
	  dont-cares) are larger than 'width' in bit size.
	  It's possible I made that mistake myself recently.
	- And although it's not an error, run the terms through
	  sort and uniq before converting to bitstrings. It
	  makes visual inspection of the debug output easier.
0.09
     2016-6-27
	- Found a case where don't-care terms with no covers
	  were nonetheless included with the prime implicants.
	  Fixed by changing a map{}-everything-will-work into
	  a loop with an if statement to check for that.
	- New test file 25-solve.t (Rock Paper Scissors) that
	  covers the above problem.
	- Streamlined the bit term functions, and added some
	  more 'smart' comments to show the bit terms.
	- Added a release_status key to the Build.PL hash.
0.08
     2016-4-21
	- Changed a "sum map" to a "scalar grep" in countels(),
	  and inlined the diffposes() code in hdist() and diffpos().
	  This let us eliminate the last cases of calling sum().
	- These changes, along with using the any() function from
	  List::MoreUtils instead of List::Util, mean that we don't
	  need to load List::Util anymore.
	- Edited Build.PL add 'provides' and 'add-to-cleanup' keys;
	  bumped the min version requirement of List::MoreUtils to 0.401;
	  Removed List::Util and bumped the dist version.
	- Module now at version 0.08.
0.07
     2015-8-14
	- List::MoreUtils wasn't in the list of required modules
	  in Build.PL. Added it.
	- The description of get_covers() in the documentation
	  wasn't enough. Extended the example.
	- Bump the version to 0.07.
0.06
     2015-8-1
	- The changes of 2015-5-30 mean that the check for an empty
	  array in row_dominance() isn't needed anymore.
	- Use a simple join() in uniqel() instead of Data::Dumper.
	- Remove Data::Dumper from 'requires' key in Build.PL.
	- Bumped Version everywhere to 0.06; up to CPAN.
0.05
     2015-7-29
	- Documented methods get_primes(), get_essentials(), and
	  get_covers().
	- Changed attribute essentials from HashRef to ArrayRef.
	  It makes get_essentials() a bit more useful.
	- Renamed tableform() function to chart().
	- Updated README to current status of the API.
	- Version 0.05 now, and up to CPAN.
0.04
     2015-6-13
	- The build-and-break-a-columnstring mechanism for making
	  complements and duals of the object was clear but involved
	  using extra memory, potentially a lot. Removed that and
	  use the get_complement() function of List::Compare::Functional
	  instead.
	- I hadn't listed namespace::autoclean in the dependency list
	  in Build.PL, and I am hearing about it from the testers.
	- Similarly, some testers have a List::Utils module that's older
	  than October 2013, when any() was introduced. Specified version
	  1.35 in Build.PL to be safe.
	- Bump everthing's version up to 0.04. Up to CPAN.
0.03
     2015-6-12
	- The minimum perl required was 5.10.1, but the module
	  was using the /r modifier on the tr// operator, which
	  doesn't appear until 5.14. Oops. Changed the string
	  assignment order in dual() and complement().
	- Version goes to 0.03, and up to CPAN.
0.02
     2015-6-11
	- Realized that the maskmatcher regex could be changed to
	  not require the don't-care character, which means it doesn't
	  need to be in the parameter list of maskmatcher(),
	  purge_elements(), or remels().
	- Renamed maskmatcher() maskedmatch(), because the grammar
	  was bugging me.
	- With that, Version 0.02 is ready for CPAN.
     2015-6-3
	- Util.pm now has an %EXPORT_TAGS.
	- Change the covers attribute to contain all of the minimal
	  covers, not just the one that happens to be in the zeroth
	  position in the covers array.
	- Change solve() to return a scalar.
	- With solve() now returning a scalar, change tests to look
	  for an answer in a set of possible answers (some terms sets
	  can be covered by more than one equation.)
     2015-5-30
	- Make remels() remove the hash key if the array ref is empty.
	- Change columns() to not auto-create empty keys.
     2015-4-18
	- Made the primes attribute "lazy", so that one can look
	  up prime implicants without going through the solving
	  process.
     2015-4-15
	- Replace row_dom() and col_dom() with row_dominance()
	  in Util.pm. When they were changed to returning keys
	  instead of deleting from the hash immediately, they
	  became essentially the same function, just called
	  with different parameters.
     2015-3-27
	- Changed row_dom() and col_dom() to return the rows/cols
	  to remove, instead of removing them inside.
	- Changed row_dom() and col_dom() from methods to functions,
	  and moved the code to Util.pm
     2015-3-6
	- Method find_essentials() is essentially a single-term search
	  through the hash of arrays. Changed it from a method to a
	  function and moved it to Util.pm.
	- Found an error in remels(), which was only removing one
	  matched array element instead of all matched elements.
     2015-1-26
	- Changed argument list to purge_essentials(). Had been
	  taking an esssentials hash, but since it was only using the
	  keys of the hash, we only need to pass those.
	- In purge_essentials() change the order of deletion. The
	  primes hash "rows" (hash entries) are removed first,
	  *before* going through the hash to look for the "column"
	  in the array ref. Shortens the search for the "column".
	- The argument list change lets me use purge_essentials()
	  later in recurse_solve(), replacing a remels()/delete
	  pair of lines.
	- Renamed purge_essentials() to purge_elements(), since
	  the above change means we're not just purging essentials
	  now.
     2015-1-18
	- Removed sortterms attribute -- always sort.
	- Simplified covers loop (helped by removing sortterms).
	- Moved a constant calculation of the %reduced hash out
	  a loop.
     2015-1-16
	- New function tableformat() (current name, at least) to show
	  primes hash in the table form used in textbook Quine-McCluskey
	  descriptions. Should help users understand what's going on,
	  and help in debugging too.
	- New module to contain tableforms() (and future functions),
	  named it Algorithm::QuineMcCluskey::Format.
	- Do-while using is_LequivalentR() was supposed to be comparing
	  hash keys, but a 'keys' had been left off on one side.
	  Fixing that saves at least one loop.
	- Avoid calling recurse_solve() if the reduced primes hash is
	  empty.
     2015-1-6
	- Added new object-creating methods dual() and complement().
	- Added tests for the new methods.
     2015-1-1
	- No default parameters for find_essentials(). The primes
	  hash must be passed in, while the binary-formatted terms
	  are collectd from the object.
	- Found spots in QM.pm and Util.pm where a "sum map {}"
	  construct can be replaced with "any {}", which has the
	  advantage of early break out of the loop on a match.
     2014-12-3
	- The weight count in find_primes() and the cost count in
	  recursive_solve() were using sum of a map block using
	  split. A match in list context is much simpler, changed
	  them to that (and put the function for it in Util.pm).
     2014-11-27
	- Add \Q and \E around don't-care character in maskmatcher()
	  substitution code in case someone chose a substitution
	  metacharacter as their don't-care character.
     2014-11-26
	- Was looping around remel() for each arrayref in the hash.
	  Now just pass the hash in directly (this necessitated
	  changing one of the outer loops in purge_essentials,
	  and remel() becomes remels()).
     2014-11-13
	- The test with don't-care terms randomly fails two thirds
	  of the time. Separate it into its own file, and add
	  debugging statements.

     2014-11-4
	- Extended the object test to consider minterms, maxterms,
	  and columnstrings methods of creation.
	- deAlias considered finished and merged into the master
	  branch.
     2014-10-31
	- Added columnstring attribute, and wrote bitstring code
	  for setting and getting it.
	- Changed minterms, maxterms, and dontcares back to
	  'rw', allowing the columnstring attribute to set them.
     2014-10-28
	- Changed to_boolean() to take an argument list instead of
	  automatically using the covers attribute internally. This
	  will allow the user (or the test files) to check terms before
	  or during minimization.
	- Separated out the var-by-var code from to_boolean(). Now it
	  calls a new method to_boolean_term() for each individual term
	  in the covers (or other) list, for easier output manipulation.
     2014-09-28
	- The 'covers' attribute gets changed from ArrayRef[Int] to
	  ArrayRef[Str].
     2014-09-21
	- Added namespace::autoclean as recommended in the Moose Best
	  Practices manual.
	- Changed the all the "terms" attributes to 'ro'.
     2014-09-19
	- For internal clarity, renamed allterms() to all_bit_terms(),
	  and minmax_terms() to minmax_bit_terms().
	- Methods maskmatch() and maskmatches() now combined into a single
	  method (one called the other, but there was no reason for the
	  separate internal function, and it saved re-creating
	  utility variables over and over).
	- Check if there's an overlap between the don't-care list and
	  the min or max term list, and call it an error if there is.
	- Attributes actually check their type now (thanks Moose) so
	  the qw operators around the term lists are now removed in
	  the documentation and in the test files.
     2014-08-20
	- No more default arguments (in the form of $self->get_primes())
	  for row_dom(), col_dom(), and purge_essentials()). Always
	  pass in the argument -- it's less confusing that way.
	- Trim Util.pm of tobits() -- it's embedded in BUILD now.
     2014-08-19
	- More work in find_primes(). An array slice in a hash isn't
	  working as originally coded (I seem to recall the rules
	  changing some time ago). Changed it to two statements for
	  now.
     2014-07-07
	- After looking over the labeling in the run.t file, added
	  a new attribute, "title". We can now say what the A::QMcC
	  object actually represents.
	- Broke up run.t into separate test files. The original
	  file was compact and in theory easy to add to, but I was
	  having trouble figuring out what was causing my Moose
	  errors. Plus, there were too many eval calls in the code.
	- The original code changed the minterms, maxterms, and
	  dontcares attributes from the passed-in list of decimal
	  into bitstrings, and saved them back in the attributes.
	  We can't do that now, because Moose has set those fields
	  typed as 'ArrarRef[Int]'.
	  So, set up three new fields that represent the three fields
	  in their bitstring form: min_bits, max_bits, and dc_bits.
     2014-04-30
	- Moosified ("has" declarations) the attributes.
	- Achieved a compile-error-free version using Moose instead
	  of Alias. Now to make it runtime-error-free.
	- As part of the compilation process, moved from a Makefile.PL
	  base (which was creating errors of its own) to Build.PL,
	  which Just Works.
	- Turned attributes boolean, imp, and bits into a local
	  variables as they were only used in single functions.
	- Defined and made use of predicate functions for attributes
	  minterms, maxterms, and dontcares. Simplifies some sanity
	  checks.
	- Added methods allterms() and minmax_terms() to simplify
	  coding.
	- List::MoreUtils isn't actually being used in A::QMcC (it is
	  used in A::QMcC::Util though).

0.01	2006-06-24T21:32-0500
		First version, released on an unsuspecting world. Supports
		single-output problems only.

