# JAS web-log

For a detailed list of the latest changes see the Subversion change log.

2012, May
  More, refactored and fixed algorithms for Wu-Ritt characteristic sets in class `CharacteristicSetWu`. Unit tests are in `CharSetTest`. jython and jruby script access to characteristic set algorithms in methods `CS()`, `isCS()`, `csReduction()`. Small fixes and improvements.
2012, March
  The Jython and JRuby scripting classes `PolyRing` are now injecting the polynomial ring variables into the top level interpreter environment by default. New class `GroebnerBaseFGLM` to compute a Gröbner base according to the "FGLM" algorithm. It computes a Gröbner base with respect to a graded term order and then constructs the Gröbner base with respect to the requested term order via linear algebra in the residue class ring. Changes from '`{}`' to '`()`' in `GenPolynomial` to string conversion. New launcher shell script `jas`. Small fixes, improvements and a missing method implemented and in `PolyUtilApp`.
2012, February
  Refactorings to simplify type parameters and loosen type conditions. New package `edu.jas.ufdroot` to remove cyclic package dependencies again. Improved selection of factorization implementations in `FactorFactory` classes and better suited constructors of the factorization implementations. Small fixes and improvements.
2012, January
  Some algorithms for Wu-Ritt characteristic sets and unit tests in class `PolyGBUtil`. Small fixes and improvements.
2011, Sylvester
  Modular variants and parallel proxy versions of resultant algorithms implemented. Cleanup and filled missing methods in `GreatestCommonDivisor*` classes in the `edu.jas.ufd` package. Fixed `ModLong` to `ModInteger` conversion. Small fixes, improvements and refactorings of methods to right classes.
2011, December
  Switched to Java 7 for development. JAS will still compile and run on Java 6 and Java 5. A new online repositoriy for JAS on Google code which contains a bug-tracker. Definition of variables for polynomial ring generators in the jython and jruby scripting interface. More JRuby examples.
2011, October
  Separated test classes to new test source tree (trc). New scripting classes for Gröbner base computations according to Eder and Perry (F5, Arri, GGV) and adapted `jas.py` in JAS for the required methods. More JRuby examples. Small improvements and fixes.
2011, September - October
  Release 2.4 updates all depending packages to the latest version and prepares for JAS 3.0. Updates for Jython 2.5.2 and JRuby 1.6.4. A new index of all algorithms from the book Algorithms for Computer Algebra by Geddes & Czapor & Labahn to their JAS equivalents. Small improvements and fixes again in multivariate integral polynomial factorization.
2011, September
  Bug fixes and missing cases for multivariate integral polynomial factorization with multivariate Hensel lifting. Further improvements and fixes.
2011, August
  Experimental multivariate integral polynomial factorization with multivariate Hensel lifting in method `factorsSquarefreeHensel()` in class `FactorInteger`. Improved multivariate Hensel lifting in class `HenselMultUtil`. Small improvements and fixes.
2011, June
  Experimental ideal complex root computation in method `complexAlgebraicRoots()` in class `PolyUtilApp`. Simple isolating interval refinement for real and complex roots. Alternative factoring of univariate polynomials over algebraic number fields via prime ideal decomposition in class `FactorAlgebraicPrim`. Improved parsing of complex numbers. Forced term orders in some situations and further small improvements and fixes.
2011, May
  Complex roots represented by ideal real roots, uses new class `RealAlgebraicNumber` and `RealAlgebraicRing` in package `edu.jas.application`. New experimental `RootFactory` with methods to compute complex roots for polynomials with coefficients in some complex algebraic extension field of the rational numbers. Uses the respective classes form package `edu.jas.root` in a recursive setting. New generic factorization classes `FactorRealAlgebraic` and `FactorRealReal`. Small improvement for reduced / minimal Gröbner base computation.
2011, April
  Multivariate algebraic ring / field extensions using class `ResidueRing`. Jruby and Jython versions and examples of the extension field builder. Small improvements and bug fixes for latest Eclipse and Java 1.7 version.
2011, March
  Easy to use construction of towers of extension fields in class `ExtensionFieldBuilder` with methods for algebraic and transcendental field extensions. Improvements in real and complex algebraic numbers. Improved polynomial parser for recursive representations. Small bug fixes.
2011, February
  New class `HenselMultUtil` for multivariate Hensel lifting. Will be used in polyomial factorization in the future. Some parts of greatest common divisor using multivariate Hensel lifting. The JAS source (r3408) compiles on Apache Harmony 6.0 (r991881). The unit tests pass with the exception of test cases involving object serialization.
2011, January
  New scripting interface to Ruby (JRuby). Ruby allows rational number literals as p/q, which are better than the Python tuple form (p,q). Some `toScript()` methods rewritten to reflect the Ruby language requirements and to differentiate between Ruby and Python. More precise exceptions for modular computations to return also the discovered factors.
2010, December, 28
  Cleanup of package structure so that all cyclic dependencies have been removed, see diagram. Split factory parsing parts from `GenPolynomialTokenizer` to `RingFactoryTokenizer`. Some artificial code was required to use solvable polynomials as ring elements since solvable polynomials cannot implement `RingElem<GenSolvablePolynomial<C>>`. This resulted in some cases in wrong method dispatch for the `multiply()` method due to compiler optimizations. A work around to detect and repair this is now implemented in class `GenPolynomial`.
2010, December, 18
  New critial pair selection for Gröbner base computation with syzygy based algorithm after Gebauer and Möller in class `OrderedSyzPairlist`. Refactoring of Gröbner base classes to optionally use the new pair selection. Back port of some JDK 1.6 constructs to be again compatible with JDK 1.5. Small improvements in Kronecker factor combination in class `FactorAbstract`. Fixed race condition in `ThreadPool` and improved termination detection in `Terminator`. Fixes in parallel reduced Gröbner base computations. Fixed univariate polynomial construction in `Ideal`.
2010, October
  Multivariate Taylor series expansion interface and implementation. Improved multivariate power series for standard base computation. Refactored methods to better suited classes and moved classes to decouple packages, e.g. `Quotient*` to package `edu.jas.ufd`. Fixed small bugs and cosmetic.
2010, September
  Multivariate power series in classes `MultiVarPowerSeries` and `MultiVarPowerSeriesRing`. Mora's tangent cone reduction algorithm and standard base computation for power series in package `edu.jas.ps`. Iterator over exponent vectors.
2010, August, 28
  Iterators for finite and some infinite structures and finite and infinite cartesian products of them. Fixed constructors to comply with the (new) Java memory model. Small bug fixes and improvements. More meaningful exceptions and some renamings.
2010, August, 8
  Improved the polynomial parser to accept rational numbers denoted with decimal points and to accept `BigDecimal` coefficients. Removed the use of the underscore for algebraic number coefficients in the polynomial parser. Now every recursive call of `parse()` from a ring factory is triggered by braces which can be nested to any depth. Fixed synchronization bug in solvable polynomial relation tables and a parallelization bug in parallel solvable polynomial Gröbner base computation. Use of unbounded thread pools to avoid dead-locks. Added remaining parts for the square-free decomposition in polynomial rings of characteristic p > 0. Changed the script representation of `AN` (`AlgebraicNumber`s).
2010, July
  Downgraded for Java 5 language and run-time system for use with systems relying on older Java versions, for example MathPiper and GeoGebra. New class `edu.jas.kern.TimeStatus` to provide user feedback for long running tasks via method `checkTime()`. Implemented some missing `extGB()` methods. `GBFactory` for the selection of appropriate Gröbner base implementations. New method `isFinite()` for all `ElemFactory`s and usage in `SquarefreeFactory`. Added some missing parts for the factorization in polynomial rings of characteristic p > 0 and ideal decomposition.
2010, June
  Factory for Gröbner base algorithm implementations in class `GBFactory`. New `GBProxy` like `GCDProxy` to run a sequential and a parallel Gröbner base computation concurrently. Primitive element computation via `normalPositionFor()` in methods `primitiveElement()` together with several conversion methods `convertToPrimitiveElem()`. A new index of all algorithms from the book Gröbner bases to their JAS equivalents.
2010, May, 28
  Implementation of arbitrary dimensional ideal radical-, irreducible-, prime- and primary-decomposition in class `Ideal` with methods `radicalDecomposition()`, `decomposition()`, `primeDecomposition()` and `primaryDecomposition()`. Computation of extension and contraction ideals. Unit tests for the decomposition methods. Fixed a bug in multivariate polynomial factorization in Kronecker's method. Fixed a bug in squarefree decomposition in inseparable case. Added `NO_THREADS` flag to `edu.jas.kern.ComputerThreads` to avoid (some) thread creation for usage in Google app engine.
2010, May, 8
  Implementation of zero dimensional ideal radical-, prime-, primary- and root-decomposition in class `Ideal` with methods `zeroDimRadicalDecomposition()`, `zeroDimDecomposition()`, `zeroDimPrimeDecomposition()`, `zeroDimPrimaryDecomposition()` and `zeroDimRootDecomposition()`. Exact 0-dim ideal real root computation and approximation in methods `PolyUtilApp.realAlgebraicRoots()` and `decimalApproximation()`. Small enhancements to Javadoc comments.
2010, April
  Some more documentation for package `edu.jas.ufd`, simplified and improved the factory classes. Refactorings of parallel Gröbner bases computations for solvable polynomial rings. Improved logging for distributed Gröbner bases and distributed middle-ware.
2010, March
  Decimal approximations for real and complex roots based on Newton-Raphson iteration restricted to isolating intervals or rectangles. Small enhancements for partial Gröbner bases. Added some Mersenne primes to `PrimeList`. Construction of minimal univariate polynomials in zero dimensional ideals. Supersets of complex and real roots of zero dimensional ideals. More unit tests for real and complex roots of univariate polynomials and zero dimensional ideal roots. Minor enhancements and fixes.
2010, February
  Gröbner bases for sub-sets of variables in class `GroebnerBasePartial`. Small enhancements: polynomial recursive coefficient parser and a matrix parser. Book-keeping of all used polynomial variable names. New and improved unit tests.
2010, January
  Factorization for polynomials with `Complex` coefficients via algebraic coefficients in Q(i). New classes `ModLong` and `ModLongRing` for faster modular arithmetic. New interfaces `Modular` and `ModularRingFactory` implemented also by `ModInteger` to make both interchangable. Improved factorization and serveral refactorings. Factorization mod p = 2 is now implemented.
2009, December
  Added a Git repository and a link to Ohloh code analysis of JAS. Cosmetic, small updates and a simple Java scripting interface. New classes for complex root isolation `ComplexRoots`, `ComplexRootsAbstract`, `ComplexRootsSturm`. The implementation provides an exact infallible method which follows the numeric method of Wilf. It uses Sturm sequences following the Routh-Hurwitz Method to count the number of complex roots within a rectangle in the complex plane.
2009, November
  New package for the elementary integration of rational functions developed together with Axel Kramer during the computer algebra seminar 2009. The implementation is based on the book Bronstein: Symbolic Integration I. New adapter (commons-math_adapter.jar) for JAS to the Apache Commons Math library version 2.0 by Axel Kramer. Cosmetic, small updates and a jython example for integration.
2009, September
  Improved comprehensive Gröbner bases with explicit classes for several alternative implementations of multiplicative sets. Base class is `MultiplicativeSet`, in sub-classes polynomials made co-prime in `MultiplicativeSetCoPrime`, polynomials made co-prime and squarefree in `MultiplicativeSetSquarefree` and polynomials made irreducible in `MultiplicativeSetFactors`. New distributed hybrid Gröbner base computation with new class `TaggedMesageChannel` to handle multiple message types and partners over one socket connection. Improved object serialization in distributed hash table. Adapter updated for JLinAlg version 0.6.
2009, August
  New adaptor classes (jlinalg_adapter.jar) to use the linear algebra library JLinAlg from JAS. Improvements in the distributed Gröbner bases algorithms. Minor fixes and improvements.
2009, July
  Code and output cosmetic, minor fixes and improvements. New interface `ToRational` used for `BigRational` and `RealAlgebraicNumber` to remove type case distinctions in `Interval`. `clone()` removed from `Element` interface because of compiler changes.
2009, June and July
  Improved absolute factorization for splitting fields. Fixes and further improvements. Implemented factorization over inseparable field extensions. Fixed squarefree factorization and added unit test. Refactored squarefree tests to separate classes. Refactored squarefree algorithms to separate classes. Interface is `Squarefree`, abstract class is `SquarefreeAbstract`. Other main classes are `SquarefreeFieldChar0`, `SquarefreeFiniteFieldCharP` and `SquarefreeInfiniteFieldCharP`.
2009, June
  Improved algebraic and absolute factorization. `FactorAlgebraic` can now also handle factorizations over multiple algebraic extensions like for example Q(i)(sqrt(2)). Class `FactorAbsolute` is now also extended by `FactorAlgebraic`, so that absolute factorizations can be computed over algebraic extensions of Q. Added new containers for absolute factorization results and tests for correct absolute factorizations. More `toScript()` methods and improvements in Jython script interface. Minor additions and fixes.
2009, May
  Improved Jython script interface to handle most of the implemented rings, developed in cooperation with Raphael Jolly. New or improved Python functions `ZZ, ZM, QQ, DD, CC, Quat, Oct`, `PolyRing, AN, RealN, RF, RC, LC, SolvPolyRing` and `RR, PS, Vec, Mat` for the construction of rings and elements. Added generic `Complex` class and `ComplexRing` factory. Fixed a programming bug in factorization code.
2009, April
  Added `factory()` method to `Element` interface to have an uniform way to obtain a corresponing ring object. Improved `RealAlgebraicNumber` so that it can be used as polynomial coefficients, for example `GenPolynomial<RealAlgebricNumber<BigRational>>`. Real root isolation can now also be used for polynomials with real algebraic coefficients, for example `RealRootsSturm<RealAlgebraicNumber<BigRational>>`.
2009, March
  Implemented univariate polynomial real root isolation algorithms and real algebraic numbers in package `edu.jas.root` during CISIS/ECDS 2009. Reached 100.000 lines of Java code.
2009, February
  Finished first version of polynomial factorization algorithms. Refactored package names `edu.jas.ring` to `edu.jas.gb` and `edu.jas.module` to `edu.jas.gbmod`.
2009, January
  Switch to version 2.3 with experimental factorization of polynomials. `Factorization` interface with `FactorAbstract` class for common codes. Factorization of univariate polynomials with several coefficient rings: modulo primes in class `FactorModular`, over integers in class `FactorInteger`, over rational numbers in class `FactorRational` and over algebraic numbers in class `FactorAlgebraic<C>` (where `C` can be `ModInteger` or `BigRational`). Multivatiate polynomials are reduced to the univariate polynomials via Kronecker substitution and are therefore not very efficient. Refactorings and fixes.
2008, December
  Fixed squarefree part and factor computation for modular coefficients. Fixed polynomial `compareTo` to be transitive as required by Javas `SortedMap` implementations. Implemented an adaptor package for Apache Log4j to delegate logging calls to native Java logging.
2008, September
  Implemented univariate power series during ADG2008 as `RingElem` and `RingFactory` types in package `edu.jas.ps` in classes `UnivPowerSeries` and `UnivPowerSeriesRing`. The implementation follows the "Infinite Streams in Java" paper of D. Gruntz in PPPJ2006.
2008, August, 11
  Added jython html documentation generated by epydoc. Added jython module to allow native polynomial expression input.
2008, August, 8
  New release 2.2. Implemented interface to use JAS as an meditor engine, see jscl-meditor.
2008, July
  Finished implementation of comprehensive Groebner bases via Groebner systems. Object oriented class layout uses `Condition` and `ColoredSystem` classes. `Condition`s consist of an ideal (with lazy Groebner base computation) for the conditions equal to zero and a multiplicative set for the conditions not equal to zero. Non-zero condition polynomials are reduced modulo the ideal of condition zero polynomials. The squarefree part from both condition polynomials is used. It differs from the MAS implementation by Schoenfeld, Pesch and others by the ideal used to store the zero conditions and some more details.
2008, June
  Added dimension computation to Ideal. Added term order optimization method to Ideal. Refactored ExpVector for different storage unit implementations of the exponent arrays. Supported storage units are `long`, `int` (now the default, as seems to be the fastest), `short` and `byte`. The respective classes are `ExpVectorLong`, `ExpVectorInteger`, `ExpVectorShort` and `ExpVectorByte`.
2008, January and February
  Added Groebner bases for polynomial rings over regular rings `RGroebnerBaseSeq` and `RGroebnerBasePseudoSeq`. Refactorings and fixes.
2007, November and December
  Added von Neuman regular rings as (finite) direct products of rings, `Product` and `RegularRingElem`. Added fraction free pseudo reduction and Groebner bases `GroebnerBasePseudoSeq`. Minor refactorings and fixes.
2007, October
  Added Groebner bases in polynomial rings over principal ideal domains and Euclidean domains, so called D- and E-Groebner bases, `DGroebnerBaseSeq` and `EGroebnerBaseSeq`. Added test methods for reducibility and refactored sequential Groebner base implementations.
2007, September
  Minor refactorings and fixes. Modular rational functions and related conversions.
2007, August, 19
  Added term order optimization for polynomial and rational function coefficients.
2007, August, 12
  Cleanup of UFD code and subversion exports. Term order optimization also available in jython.
2007, July, 28
  Added term order optimization class from old DIP/MAS system. This introduced a dependency on JDK 1.6. Refactored source tree to allow fully functional subversion exports.
2007, July, 12
  New global class edu.jas.kern.ComputerThreads to represent a thread pool. To stop JAS, when the pool has been started, it is required to call ComputerThreads.terminate().
2007, July, 11
  New preemptive cancellation handling. Introduced class PreemptingException as runtime exception and a global class PreemptStatus to allow or deny preemption cancellation. GenPolynomialRing queries PreemptStatus upon creation. GenPolynomial checks preempt cancellation handling and thread interrupt status on construction. If preemption is requested, it throws PreemptingException. This allows e.g. GCDProxy to ignore the respective sub-task and get the thread free. Removed explicit isInterrupted() checks in edu.jas.ufd package.
2007, July, 10
  Refactored generation of (lists of) univariate polynomials from SolvableGroebnerBase* to GenSolvablePolynomialRing and GenPolynomialRing. Implemented generic Power class in edu.jas.structure, refactored power() in subresultant PRS.
2007, July, 9
  Added unit tests for distributive law in arith and poly packages. Review of all documentation comments.
2007, July, 8
  Added assertions to check for number of polynomial variables in GenPolynomial. In ModInteger and AlgebraicNumber inverse() now throws a NotInvertibleExecption, which extends runtime exception. Fixed some correctness bugs detected by Findbugs.
2007, July, 7
  Refactored ModInteger for ModIntegerRing factory. Changed all depending classes. Refactored GenPolynomial.getMap() to return unmodifiable SortedMap. Refactored GenPolynomial.val using methods from jas.ufd package to jas.poly package. ExpVector.getVal() renamed and made package private. Logger variables now also final.
2007, June, 10
  Improved InterruptedException handling. Refactored use of edu.ky.parallel package to use edu.jas.util and java.util.concurrent. Refactored project web-site.
2007, April and May
  Implementation of greatest common divisor algorithms. Using recursive types. Implemented remainder sequences: primitive, monic, subresultant. Implemented modular methods with chinese remaindering for ModIntegers and evaluation in finite fields to reduce the number of variables. Implemented Hensel lifting: linear and quadratic; mod ideal is still missing. Factory classes to select "best" implementations. Proxy classes to run probable good implementations in parallel, taking the result of the first terminating algorithm. Refactored many classes to fit for the new requirements. New method characteristic() in RingFactory and implementing classes. Changed Quotient (rational function) to use new gcd algorithms. Can compute GBs for polynomials with rational function coefficients.
2006, March
  Refactored ring package to separate application package with more application of Groebner bases oriented classes. The ring package could now be renamed to gb package. Cosmetic and documentation improvements, e.g. javadoc package descriptions and type parameter tags, removed all tabs in all java files. Implemented generic Quotient(Ring), Residue(Ring) and Local(Ring).
2006, February, 27
  Implemented parallel solvable Groebner base algorithms and tests. New class distributed ThreadPool. Cosmetic and code improvements spotted by eclipse, lint4j and jdepend. Refactored module package to separate vector package with basic linear algebra and list handling classes. Refactored to allow different Groebner base or reduction engines where appropriate. Split Syzygy etc. to an interface and a class. Factored basic linear algebra out of Syzygy etc. Adapted jython files to Jave code refactorings. Reorganized jar files and documentation.
2006, February, 12
  Moved old examples to MAS subdirectory and new examples to examples directory. Implemented some right version algorithms using opposite rings. Switched to subversion from cvs. Fixed bugs in new left syzygy algorithm.
2006, January
  More documentation and cosmetic. Implementation of an extended Groebner Base algorithm and arbitrary base syzygy computation. GenPolynomialTokenizer enhanced to parse algebraic number and Galois field coefficients. Fixed an error in leftNormalform.
2005, 12, 30
  New classes CriticalPair and CriticalPairList replace OrderedPairlist. Reworked GB parallel and distributed versions to better respect sequential version critical pair sequences. Fixed some race conditions in parallel and distributed algorithms.
2005, 12, 28
  Refactored all classes to remove static methods. So to use any method at first an appropriate object is required. Also class organization has changed to interfaces, abstract classes and concrete classes, e.g. GroebnerBase, GroebnerBaseAbstract, GroebnerBaseSeq, GroebnerBaseParallel and GroebnerBaseDistributed.
2005, 12, 27
  Implemented new Ideal class with some ideal operations like sum, product, intersection and quotient. Added TermOrder extension and contraction.
2005, 11-12
  Updated documentation comments.
2005, 7, 24
  Updated old Java JDK 1.4 branch. Bugfixes (in twoSidedGB), minor changes and cosmetic.
  Updated documentation for new Java JDK 1.5 branch.
2005, 5-7
  Working through all classes to introduce type parameters and making all implied modifications.
2005, 5, 5
  Switched to Java 1.5. Now using covariant returns for implemented interfaces.
2005, 3, 25-29
  Some module algorithms implemented. Activated project web pages.
2005, 3, 12-19
  Some Syzygy algorithms implemented. Cosmetic on comments and forked web-log.
2005, 3, 5
  For the python languege and interpreter exists also a Java version named jython. This system can directly access Java classes and execute Java methods. Added some jython modules Ring, Ideal, SolvRing and SolvIdeal, to access jas GB algorithms from jython.
2005, 2, 25-28
  Penality of commutative GB computed as non-commutative left GB is about 24% for (graded) Katsura 6 to 74% for (graded) Katsura 5. Commutative GB computed as non-commutative twosided GB is about a factor of 4 for (graded) Katsura 5 to a factor of 9 for (graded) Katsura 5. Penality for weighted degree term order compated to graded Term order is not measurable or sometimes better. Fixed error in polynomial getONE() to correct term order. Parser for non-commutative problems with relation tables (but only commutative representations) and RunSGB main routine.
2005, 2, 14-21
  New TermOrder with direct generation of Comparators for ExpVector comparisons. Split term orders (elimination orders) and weighted degree orders.
2005, 2, 4-8
  New unit test case for TermOrder. Fixed weak point in polynomial getONE() to correct number of variables, e.g. correct exponent vector size. Polynomial constant ONE still has wrong exponent vector size. Deleted many old polynomial classes.

  Implemented noncommutative product for solvable polynomials, together with relation tables. SolvableOrderedMapPolynomial extends OrderedMapPolynomial. RatSolvableOrderedMapPolynomial extends SolvableOrderedMapPolynomial. Interface SolvablePolynomial extends Ordered Polynomial. Some more left multiplication methods, left reduction and left Groebner Bases, twosided Groebner Base test and computation. Pairlist class changed to avoid usage of criterion 4 if running for SolvablePolynomials, also criterion4() method itself checks for SolvablePolynomials.

  RelationTable timings I, U(sl_3)
  run / n | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15
  --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
  first | 3 | 13 | 32 | 92 | 128 | 188 | 274 | 420 | 683 | 1126 | 1795 | 2793 | 4380 | 6741
  second | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 8 | 10 | 13 | 16 | 21 | 27 | 35

  Timings in ms on AMD XP 2800+. Computation of (Y^n) * (X^n) with respect to the relation Y * X = X Y - H. In the first run the relation table is populated with the products Y^i * X^i, i = 2,...,n. In the second run the relations are reused, showing almost no computing time anymore for the products.

  RelationTable timings II, U(sl_3)
  run / n | 2 | 3 | 4 | 5 | 6 | 7
  --- | --- | --- | --- | --- | --- | ---
  first | 28 | 94 | 303 | 1234 | 5185 | 24647
  second | 1 | 12 | 107 | 782 | 4569 | 23897

  Second example shows the computation of ( Xa + Xb + Xc + Ya + Yb + Yc + Ha + Hb )^n in U(sl_3). Since in the relation table only products of two variables are stored, the improvement is minimal (for low n).

2005, 1, 24-31
  Removed old deprecated classes. Todo: let DistHashTable implement Map Interface. Reimplemented Reduction.Normalform so that asynchronous update of the polynomial list is possible and respected. In case a new polynomial arrives, the reduction is restarted from the beginning. Continuing with the done work and rereducing so far irreducible terms would be an alternative. Todo: use JDK 1.5 java.util.concurrent with interference free Lists, BlockingQueues.

  Distributed computation timings, Katsura 6 (G)
  # Threads CPUs | # JVMs | time (sec) | #put | #remove | % total
  --- | --- | --- | --- | --- | ---
  1, seq | 1 | 160.2 | 70 | 327 | 13.5
  1, par | 1 | 157.0 | 70 | 327 | 13.5
  2, par | 1 | 82.2 | 72 | 329 | 12.7
  1, dist | 1 | 177.2 | 77 | 334 | 11.4
  2, dist | 2 | 92.2 | 90 | 347 | 8.6
  4, dist | 2 | 56.2 | 112 | 369 | 5.9
  8, dist | 2 | 58.9 | 255 | 516 | 1.5
  4, dist | 4 | 51.2 | 117 | 374 | 5.5
  6, dist | 4 | 43.7 | 129 | 386 | 4.6
  8, dist | 4 | 62.9 | 259 | 519 | 1.5

  Timings taken on a 16 CPU Intel Xeon SMP computer running at 2.7 GHz and with 32 GB RAM. JVM 1.4.2 started with AggressiveHeap and UseParallelGC.
  #JVMs = number of distinct Java virtual machines. #put = number of polynomials put to pair list. #remove = number of pairs removed from pair list, i.e. after application of criterions, but including nulls up to now. % total = per cent of removed pairs from total pairs generated, #remove / ( #put * (#put-1) / 2 ) * 100.

  Distributed computation timings, Katsura 7 (G)
  # Threads CPUs | # JVMs | time (sec) | #put | #remove | % total
  --- | --- | --- | --- | --- | ---
  1, dist | 1 | 24726.2 | 140 | 781 | 8.0
  2, dist | 2 | 12356.1 | 165 | 806 | 5.9
  4, dist | 4 | 6859.3 | 218 | 859 | 3.6
  8, dist | 4 | 7465.1 | 411 | 1054 | 1.2
  8, dist | 8 | 6412.9 | 344 | 986 | 1.6
  8, dist | 8 | 7173.3 | 399 | 1041 | 1.3

  Overhead for distributed variant is about 10% in Katsura 6 (G). Distributed 1 means one distributed process is running for the reduction of S-polynomials. There is always a master process handling polynomial input / output, setup and management of distributed workers and handling of the pair list. Communication between master and workers is always via TCP/IP with object serialization, even if running on one computer.

2005, 1, 15-16
  Further things to improve in GB algorithms (from tsp): local work queues, i.e. local Pairlists, improve data locality in polynomials and lists, communication using message types, reduce object serialization in DL-broadcast by using MarshalledObjects, reduce communication in Pair send by not sending polynomials but indicies (requires distributed hashtable instead of DL), interleave communication and computation by adding a communication thread in the distributed client.

  New classes implementing a distributed hash table to hold the polynomials in distributed GB. Index of polynomials in Pairlist is used as hash key. Communication is now using message types GBTransportMess. Now polynomials are only transported once to each reducer since only polynomial hash indexes are transported. Distributed list is asynchronous and late updated, so some duplicate H-polynomials (head terms) could be (are) produced. Solution by local put to hash table with dummy index? Timings are not dramatically better.

  Todo: check reduction algorithm to use later arriving polynomials.

2005, 1, 9-14
  Introduced all direct improvements in util classes found so far. (ChannelFactory and others) On parallel computers the following JVM options (1.4.2) must be used:

        -Xms200M -Xmx400M -XX:+AggressiveHeap -XX:+UseParallelGC

  Memory must be adjusted with respect to your situation.

  Seperated versions with Pair Sequence Respecting Order (PS) and normal versions. PS versions try to keep the order of reduced polynomials added to the ideal base the same as in the sequential version. Normal versions now running OK on parallel computer with the right JVM options. Refactoring with Eclipse (organize imports, static methods).

  Parallel computation timings, Katsura examples
  # Threads CPUs | Katsura 6 TO(G) load* | Katsura 6 TO(G) empty* | Katsura 7 TO(G) load* | Katsura 7 TO(G) empty*
  --- | --- | --- | --- | ---
  seq | 184.5 | 153.3 |  |
  1 | 181.5 | 4% / 159.7 |  | 28418.6
  2 | 118.6 | s2.02 / p2.11 / 75.6 |  | p2.06 / 13760.0
  4 | 76.8 | s3.79 / p3.95 / 40.4 | 6256.9 | p4.56 / 6225.1
  8 | 43.2 | s7.19 / p7.49 / 21.3 | 3240.7 | p8.56/ 3318.8
  10 | 42.5 |  |  |
  12 | 40.5 |  | 2288.1 | p9.90 / 2868.4
  14 | 31.2 |  |  |
  16 | 51.9 | s8.19 / p8.54 / 18.7 | 5376.4 | p12.59 / 2256.1

  Timings taken on a 16 CPU Intel Xeon SMP computer running at 2.7 GHz and with 32 GB RAM. JVM 1.4.2 started with AggressiveHeap and UseParallelGC.
  *) timing taken with other load on the CPUs. +) timing taken with no other load on the CPUs.
  Speedup: s = relative to sequential, p = relative to parallel with one thread / CPU.
  Scaling from 8 to 16 CPUs is bad, but also observed on non CA / GB Examples (Java and C/FORTRAN).

2004, 10, 3
  Generator for Katsura examples (from POSSO / FRISCO examples). Timings on an AMD Athlon XP 2800 (2086MHz) with log level INFO. Log level WARN would gain 10-20 %.

  Timings Katsura examples
  N vars = N+1 | TermOrder | Seconds | TermOrder | Seconds
  --- | --- | --- | --- | ---
  7 | G | 32044.204 | L |
  6 | G | 112.641 | L |
  5 | G | 4.195 | L |
  4 | G | 0.431 | L | 11.650
  3 | G | 0.153 | L | 0.310
  2 | G | 0.031 | L | 0.032

2004, 9, 20-26
  Changed OrderedPairlist to record the sequence of pairs taken from the list. New methods `putParallel()`, `removeParallel()` and helper methods. Sequence numbers are generated and reduced polynomials are only put to the pair list if corresponding pair number is in correct (sequential) sequence. The ordered list / queue `pairsequence` (TreeMap/SortedMap) keeps track of the polynomials not yet put to the pairlist.
  Parallelism is possible as long there are pairs to be reduced. But non zero reduced polynomials are only put into the pairlist if the polynomial would be put into the pairlist in the sequential Buchberger algorithm. GroebnerBase algorithms had to be modified to record that a polynomial reduced to zero.
2004, 9, 19
  Changed order of Pair inserts for pairs with same LCM of HTs. Added sequence number to each Pair and indicator if Pair did not reduce to zero.
2004, September
  Implemented Java server (`ExecutableServer`) for remote execution of objects implementing the `RemoteExecutable` interface.

  New setup for the distributed computation of GBs: the GB master now sends the client code to some ExecutableSevers based on a maschine file with host and port infos about the distributed environment.

  Improved the PolynomialTokenizer so that it can read almost unedited old MAS GB input files: `**` exponents and parenthesis around polynomials. Lines starting with `#` are treated as comments. Comments `(* *)` and parenthesis within polynomials are still not supported.

  Implemented a common driver for GB computations `RunGB`. Sequential, thread parallel and distributed computation can be selected by command line parameters. The input is taken from a file. The number of threads respectively the number of distributed clients can be specified. For distributed execution the host and port information is taken from a maschines file.

      Usage: RunGB [seq|par|dist|cli] <file> #procs [machinefile]

  Added methods `putCount()` and `remCount()` in `OrderedPairlist` to count the number of polynomials put and get from the pair data structure.

  pairlist put and remove, trinks6
  # Threads | 1 seq | 1 par | 2 par | 2 par | 3 par | 4 par | 5 par | 1 dist | 2 dist | 3 dist | 4 dist | 4 dist | 4 dist | 5 dist
  # put | 22 | 22 | 43 | 26 | 28 | 28 | 28 | 22 | 25 | 28 | 37 | 40 | 33 | 27
  # remove | 25 | 25 | 61 | 30 | 32 | 32 | 41 | 26 | 33 | 42 | 47 | 61 | 54 | 69

  Timings @ 500 MHz on one CPU and one maschine and log4j level INFO are:
  ca. 2.5 - 3.5 seconds for sequential GB,
  ca. 2.5 - 6 seconds for parallel GB,
  ca. 5.5 - 9 seconds plus 5 seconds sync time for distributed GB.
  Network shuffling of polynomials seems to account for 3 seconds in this example.

  Problem uncovered: the distributed version of GB needs an avarage of 5 seconds to sync with all clients (on one maschine). This is way to much for execution times in the range of 2 to 8 seconds.

  Redesign of DistributedList, now using TreeMap to keep the list entries in proper sequence. As key a natural number is used, which is assigned by the server to successive add() requests. The server now also holds a copy of the list by itself. So the retransmission of list elements to late arriving clients is possible. This doubles the space required to store polynomials, but removes initial delays to sync all clients to receive all list elements.
  By retransmission the DistributedList synchronization delay during DistributedGB could be removed. However the problem of about 5 seconds delay in startup of DistributedGB still remains. It is not visible where and why this delay occurs.
  Further improvements would be the removal of list elements or the clearing of the list. Next steps could be distributed HashMap or TreeMap.
  An important improvement would be to keep serialized copies of the list elements (polynomials) at the server and to avoid many time serialization during broadcast.

2004, 2, 26
  Ideas to implement: a distributed task launcher like `mpirun`, a daemon to run on a distributed system to work with the launcher, solvable polynomials and non-commutative GBs.
2004, 2, 1
  Parallel computations with the Rose example are at ?? h with 3 threads on 2 Pentium 4 @ 3.0 GHz hyperthreading CPUs.

  With one thread the time is 30.6 h. Besides the better CPU speed, this makes a 5 % improvement on JDK 1.4 compared to the older timings from a JDK 1.3 and the new polynomial implementation.

2004, 1, 25
  Spin model checker: Setup Promella description of parallel and distributed GB algorithm. Used to verify the safety and liveness properties of the algorithms.
2004, 1, 17
  New (minimal) class DistributedList in preparation of a distributed GB algorithm. Made all mutually transported objects Serializable. Fixed ChannelFactory and other classes in edu.unima.ky.parallel to be interuptable. Moved Semaphore back to edu.unima.ky.parallel. First version of a distributed memory GB. One problem was inner class Pair results in serialization of outer class OrderedPairlist, which is not intented. So Pair is now a proper class. Distributed version mainly working. Problem with signaling and termination if 1 in GB.
2004, 1, 10
  Refactored Groebner base for new OrderedPolynomials and split sequential and parallel GB implementations. New unit tests for sequential and parallel GBs. GB now works for arbitrary Coefficients.
2004, 1, 5
  New coefficient domains BigComplex and BigQuaternion. New test unit for all coefficients. Based on these coefficients are new polynomials, e.g. ComplexOrderedMapPolynomial and QuatOrderedMapPolynomial together with unit tests. Problem: RatPolynomial requires DEFAULT_EVORD be set correctly in ExpVector. This is now solved for the new OrderedMapPolynomials.
2003, 12, 29
  New organization of polynomials:
  2 interfaces: UnorderedPolynomial and OrderedPolynomial. Ordered polynomials have a term order and are implemented using some SortedMap (e.g. TreeMap). Unodered polynomials are implemented using some HashMap (e.g. LinkedHashMap).
  2 abstract classes: UnorderedMapPolynomial and OrderedMapPolynomial. Both implement all algorithms which do not need an explicit coeficient domain, i.e. they are formulated in terms of the Coefficient interface from jas.arith.
  2 or more classes which extend the respective abstract classes: RatUnorderedMapPolynomial and RatOrderedMapPolynomial both need explicitly coefficients from BigRational or others.

  Multiplication with ordered polynomials is about 8-10 times faster than the multiplication with unordered polynomials. Also the multiplication with semi-ordered polynomials (LinkedHashMap) with orderpreserving addition is about 7-8 times slower than multiplication with ordered polynomials.

  All implementations are based on Map interface and classes. The Map maps exponent vectors (from some monoid) to coefficients (from some domain). This is in sync with the mathematical definition of multivariate polynomials as mappings from some monoid to some domain. Term orders are represented by a TermOrder class which provides the desired Comparator classes for the SortedMap implementation.

2003, 12, 28
  Things to do: refactor and test HashPolynomial, check performance. Improve the parallel GB algorithm, e.g. parallelize the reduction algorithm. Develop a distributed memory version of the parallel GB algorithm.
2003, 12, 27
  Using ArgoUML to produce class diagramms for jas. Refactoring GB from edu.jas.poly to edu.jas.ring.
2003, 12, 21
  Setup for JUnit version 3.8.1. Added JUnit testing with Apache Ant version 1.6.0 to build.xml.
2003, September
  Experimented with LinkedHashMap instead of TreeMap (SortedMap) for the representation of polynomials. Algorithms which work also with LinkedHashMap have 1 or 2 in their names (now in new class HashPolynomial). LinkedHashMap has the property of using the insertion order for the iterator order. With LinkedHashMap the add() and subtract() can be reformulated to use a merging algorithm as in the original DIP implementation. Assuming the Map insertion order is the the same as the polynomial term order.

  However the merging add/subtact implementation is a factor of 2 slower than the TreeMap implementation. Complexity for a+b is
  2*(length(a)+length(b)) for access and merging pre sorted polynomials and
  2*length(a)+length(b)+length(b)*log2(length(a+b)) for TreeMap clone, access and insertion.

  The merging multiplication implementation is by a factor of 10 slower than the TreeMap implementation. Polynomial size was ~100 terms and the product contained ~8000 terms. Complexity for a*b is
  lab = length(a)*length(b) coefficient multiplications for both implementations
  plus 2*length(a*b)*length(b) for merging summands, respectively
  plus length(a)*length(b)*log2(length(a*b)) for TreeMap insertion. Since for sparse polynomials length(a*b) = lab, the TreeMap complexity is asymptotically better in this case:
  2*length(a)*length(b)*length(b) =>= length(a)*length(b)*log2(length(a*b))
  For dense polynomials with length(a*b) ~ length(a)[+length(b)], then the LinkedHashMap complexity is asymptotically better:
  2*length(a)*length(b) =<= length(a)*length(b)*log2(length(a*b))

2003, 3, 15
  Some testing with new AMD Athlon XP 2200+ @ 1.8 GHz, 133x2 MHz memory access.
  Trinks 6: 1.013 sec with log4j level WARN, parallel 1.058 - 1.740 sec.
  Trinks 7: 0.553 sec with log4j level WARN.
2003, 2, 2
  Replacing all System.out.println by Log4j logging calls. adding some Junit tests.
2003, 1, 28
  Some testing with gcj (Gnu Java Compiler). this compiler gernerates native executable binaries. the timings are not better than with a jit, often worser.

  Parallel computations with the Rose example are at 18 h with 4 threads on 2 Pentium 4 @ 2.4 GHz hyperthreading CPUs. With one thread the time is 40 h.

2003, 1, 26
  timings with JDK 1.3 (from IBM) are 30% to 40% faster than with JDK 1.4.1 (from Sun). timings on PowerPC 604 @ 200MHz JDK 1.3 (from IBM) JDK 1.2 (from Sun) are a factor 3.5-4.5 slower than on Intel PIII @ 450 MHz. on PowerPC not using jit is faster than using a jit, ca. 20% - 30%.
2003, 1, 12
  General differences between sequential and parallel GB algorithms
  - The parallelization is achieved by doing the normal form reductions in parallel.
  - Since the reductions may require different times to complete the normal forms may be entered into the list of polynomials in different (time) order than in the sequential case. So the pairs may be generated in different order. However since the list of pairs is ordered wrt. the lcm of the head terms this seems not to be a big issue.
  - Since several reductions are scheduled in parallel the pairs are taken from the list of pairs in different order than in the sequential case. One should not take more pairs from the list than can be reduced in parallel.

  Does this influence the validity of criterion 3? Access to pairlist is synchronized. Pairs are marked as reduced as soon they are taken from the list. But the algorithm terminates only after all reductions of pairs have terminated. So criterion 3 holds.

  New implementation of parallel version of GB. Removal of pairs is now also in parallel. But ordering of pair insertion is no more preserved

  Timings are more stable and slightly better than that of sequential GB.

  Todo: unit tests, comments, ...

2003, 1, 7-11
  Renamed jas to mas2jas, new cvs repository for jas, import and checkout.

  Improved parallel version of GB.

  - The sequence of polynomials added to the pair list is kept stable. i.e. a pair scheduled for reduction at time t will (if non zero) enter the list before any pair scheduled at time t+x.
  - This limits the parallelism since polynomials which reduce to zero keep a reducer thread occupied until older polynomials are finally reduced. One could eventualy hand over the blocking object to the next thread.
  - The number of pairs scheduled for reduction is now also limited to the number of parallel reduction threads. this avoids that to many pairs with high lcm will be scheduled before eventually new created pairs with lower lcm.
  - The limiting of scheduled pairs could also be implemented using a BoundedBuffer/Queue for the ThreadPool workpile. then addJob() would block until free Threads are avalilable.
  - The sequencing and limiting could eventually also achieved when the reducing threads take the pairs by themselves instead of the master thread. The main thread should then simply wait until all threads are idle.
  - The final reduction of the GB to a minimal GB is now also parallelized.

  Todo: CVS, comments, polynomial implementation using LinkedList, parallel GB simplify

  With the improved algorithm the running time of the parallel GB becomes more stable and not slower than the sequential GB. However there is still no significant speedup.

  parallel GB on one cpu
  # Threads | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 16
  # Reductions | 25 | 25 | 27 | 25 | 25 | 25 | 25 | 25 | 25

  parallel GB on 4 cpus
  # Threads | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 16
  # Reductions | 22 | 24 | 30, 28, 24, 29 | 28 | 29 | 42 | 32 | 32 | 37

2003, 1, 6
  implemented parallel version of GB using ThreadPool from tnj

  parallel results:
  Trinks 7: mas 0.598 sec, jas 0.918 sec, jas par 0.955 sec
  Trinks 6: mas 26.935 sec, jas 3.211 sec, jas par 3.656 sec
  mas: including startup and gc time, jas: excluding startup of jvm and including gc time, jas par on single processor timing on P-3@450

  this make for a penality of 12 percent, all tests with output to files,
2003, 1, 5
  timing benchmarks between BigRational and Coefficient versions of the algorithms, the difference seems to be less than 1 percent with no clear advantage of one side
  the sum and product algorithms have not jet optimal complexity, sum has 2 l log(l) instead of 2 l because of TreeMap.remove() and because of TreeMap.put(), prod has l^2 log(l^2/2) instead of l^2 because of TreeMap.put()
  TreeMap cannot used for this, some kind of SortedLinkedList or SortedHashMap would be required, the last would in turn require a hashValue() of an ExpVector

  implemented edu.jas.arith.BigInteger which implements Coefficient, tested with IntPolynomial which extends Polynomial

  todo: alternative Implementations, cleanup RatPolynomial, parallel GB, conversion RatPolynomial <--> IntPolynomial
2003, 1, 4
  added reading of PolynomialLists and Variable Lists to PolynomialTokenizer, implemented PolynomialList
  refactoring RatPolynomial to extend Polynomial, implementing IntPolynomial extends Polynomial
  to make BigInteger implement Coefficient will require a delegation extension of BigInteger
2003, 1, 3
  implemented PolynomialTokenizer to read RatPolynomials
2003, 1, 2
  file RatPolynomial split into RatGBase, criterion 3 implemented with BitSet

  second results (with new criterion 3 in jas):
  Trinks 7: mas 0.598 sec, jas 1.159 sec
  Trinks 6: mas 26.935 sec, jas 6.468 sec
  mas: including startup and gc time, jas: excluding startup of jvm and including gc time

  implemented DIGBMI, H-polynomal was not monic in DIRPGB

  third results (with new criterion 3 in jas and GBminimal):
  Trinks 7: mas 0.598 sec, jas 0.918 sec
  Trinks 6: mas 26.935 sec, jas 3.211 sec
  mas: including startup and gc time, jas: excluding startup of jvm and including gc time timing on P-3@450

  this makes for a factor of 8-9 better, all tests with output to files, startup of JVM is approx. 1.0-1.2 sec, most time is spent in BigInteger:

      java -Xrunhprof:cpu=times,format=a

      CPU TIME (ms) BEGIN (total = 136) Thu Jan  2 18:33:53 2003
      rank   self  accum   count trace method
         1 15,44% 15,44%  596610    21 java.math.MutableBigInteger.rightShift
         2 13,24% 28,68%  582132    15 java.math.MutableBigInteger.difference
         3 12,50% 41,18%  612760    19 java.math.MutableBigInteger.getLowestSetBit
         4  9,56% 50,74%       2     9 java.lang.Object.wait
         5  9,56% 60,29%    5271    22 java.math.MutableBigInteger.binaryGCD
         6  6,62% 66,91%  612760    23 java.math.BigInteger.trailingZeroCnt
         7  5,88% 72,79%  592152    18 java.math.BigInteger.bitLen
         8  5,88% 78,68%    6018    20 java.math.MutableBigInteger.binaryGCD
         9  5,15% 83,82%  578887    25 java.math.MutableBigInteger.normalize
        10  4,41% 88,24%  550992    24 java.math.MutableBigInteger.primitiveRightShift
        11  4,41% 92,65%       1    10 java.lang.Object.wait
        12  3,68% 96,32%  582132    12 java.math.MutableBigInteger.compare
        13  0,74% 97,06%   35965    13 edu.jas.poly.ExpVector.EVILCP
        14  0,74% 97,79%   11612    14 java.math.BigInteger.divide
        15  0,74% 98,53%    5866    11 java.math.MutableBigInteger.divide
        16  0,74% 99,26%    9032    16 java.math.MutableBigInteger.divide
        17  0,74% 100,00%   9032    17 java.math.BigInteger.divide
      CPU TIME (ms) END

2003, 1, 1
  renaming packages to edu.jas, renaming to arith, poly and ring, new Makefile, project dokumentation in XHTML, using JDK 1.4 with JIT

  first results (without criterion 3 in jas):
  Trinks 7: mas 0.598 sec, jas 1.373 sec
  Trinks 6: mas 26.935 sec, jas 30.935 sec
  mas: including startup and gc time, jas: excluding startup of jvm and including gc time. timing on P-3@450

2002, 12, 31
  starting with extraction of relevant files in new directory
2000, 7, 21
  keySet/get replaced by entrySet/getval.
  Implemented S-Polynomial, normal form, irreducible set. Implemented Groebner base with criterion 4. Criterion 3 left to to.
2000, 7, 16
  Implemented and tested BigRational based on Javas BigInteger.
  With and without I/O BigRational addition, multiplication and comparison is approx. 10 times faster than respective SACRN functions.

  Implemented and testet ExpVector based on Javas int arrays.

  Implemented and testet RatPolynomial based on Javas TreeMap.
  static methods: DIRPDF, DIRPWR via toString, DIRPON, DIRPMC, DIRPPR, DIRPSM, DIRRAS.
  Consider replacing keySet/get by entrySet/getval where appropriate. Can there be an generic Polynomial class?

2000, 7, 15
  Some testing with Javas builtin BigInteger class.
  Without I/O builtin multiplication is approx. 15 times faster than SAC product.
  With much I/O builtin multiplication is approx. 3 times faster than SAC product.
  Builtin uses also twos-complement representation, which is bad for decimal printing.

  This will be the end of list processing for Jas.

  DIPRNGB needs DIRPDF, DIRPWR, DIRPON, DIRPMC, DIRPPR, DIRPSM.
  These need RNDIF, RNDWR, RNINT, RNSIGN, ISRNONE, RNONE, RNZERO, RNINV (and DIRPRP), RNPROD, RNSUM.

2000, 7, 14
  Class BigInteger based on SACI with toString().
  Class List based on MASSTOR with toString().
  Problem with Modula-2 module initialization with main(args) method: initialization of static variables.
2000, 7, 5
  Finished testing most of masarith.
2000, 7, 2
  Finished porting masarith. Testing needs still to be done. MASAPF is ok.
2000, 6, 24
  Perl script getc.pl to grab comments in Modula-2 source and add to Java source. Comments grabbed on most working files so far. Generated new documentation.
2000, 6, 22
  Future directions:
  - Parallel GB.
  - Move to Java without Modula-2.
  - Develop an applet version.
  - Implement more of Mas.
  - Replace SACI by Java BigInteger.
  - Setup for real objects:
    implement constructor,
    implement methods: a.method(b) as STATIC_METHOD(a,b),
    use real objects instead of only Cell objects
    define interfaces e.g. for ring, polynomial ring, module, group, field
  - Small additions:
    toString equivalents of xWRITEs
  Problems identified:
  - LISTs over Beta-Integers are diffrent to LISTs over LISTs, when implementing LISTs as Java Types LISTs over other types will require also special handling.
2000, 6, 22
  GB running on Trinks (small and big). Jas ist about 5-8 times slower than MAS in GB computation. Using JDK 1.1.7 without JIT on Linux, PII-300. Using JDK 1.2.2-RC3 without JIT on Linux, PII-300 is about 6-9 times slower. Using JDK 1.2.2-RC4 with JIT (sunwjit) on Linux, PII-300 is about 2-4 times slower. Implemented Java input via BufferedReader.
2000, 6, 21
  Got GB running. Problem was in EQUAL.
2000, 6, 17
  Placed under control of CVS. Begining with a clean version from Uni Passau. Incorporated Java specific changes up to now.
2000, 6, 10
  Transformation of DIPRNGB finished. Important parts of maspoly finished.
2000, 6, 4
  Transformation of SACPRIM finished. Most of maskern finished. Important parts of masarith finished.
2000, 5, 29
  MASSTOR: Mapping MAS list direkt to a Java list class and using of the garbage collector from Java. Data types LIST and GAMMAINT are now distinct. Buying the MHC Compiler (UK Pound 59).
2000, 5, 28
  MASSTOR: First attempt to use list class with own garbage collection. Using the constructor to record list pointers.
2000, 5, 27:
  Beginning of the first tests. Conversion of .md to .def, .mi to .mod.
2000, 5, 26:
  Discovery of the MHC Modula-2 to Java compiler. Mill Hill & Canterbury Corporation, Ltd, URL http://www.mhccorp.com

## Done bevore 2003

- JUnit checker for every class.
- Switching to Java and abandoning Modula-2.
- Removal of the mas prefix in directory names.
- Improved Makefiles.

Last modified: Sun May 6 21:33:06 CEST 2012