143 lines
9.6 KiB
Plaintext
143 lines
9.6 KiB
Plaintext
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Apache Commons Math 2.1 RELEASE NOTES
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This is primarily a maintenance release, but it also includes new features and enhancements.
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Users of version 2.0 are encouraged to upgrade to 2.1, as this release includes some important
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bug fixes. See the detailed list of changes below for full description of all bug fixes and
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enhancements.
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This release contains some minor API compatibility breaks with version 2.0:
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--------------------------------------------------------------------------
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- the return type of RealVector.copy() has been changed to AbstractRealVector
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- the no-argument constructor of MatrixUtils() has been made private
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- the mapXxxToSelf methods of OpenMapRealVector have been removed and some method return types
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have been changed in this class
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- new methods have been added to the RealVector interface
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- several fields in AdaptiveStepSizeIntegrator have been made final
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- DummyStepInterpolator requires an additional argument for one of its constructors
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- some protected fields have been removed from AbstractLeastSquaresOptimizer,
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AbstractScalarDifferentiableOptimizer and AbstractLinearOptimizer
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- the isOptimal(SimplexTableau) method has been removed from SimplexSolver
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Changes in this version include:
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New features:
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o MATH-357: Implementation of bicubic interpolation.
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o Added a way to compute both the final state in an Initial Value Problem (IVP)
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for Ordinary Differential Equations (ODE) and its derivatives with respect to
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initial state and with respect to some problem parameters. This allows wrapping
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ODE solvers into optimization or root finding algorithms, which in turn can be
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used to solve Boundary Value Problems (BVP). There are no implementations (yet)
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of BVP solvers in the library.
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o MATH-323: Added SemiVariance statistic. Thanks to Larry Diamond.
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o MATH-341: Added a warning in the getCoefficients method documentation for
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PolynomialFunctionLagrangeForm. Computation may be ill-conditioned
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so this method should be used with care.
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o MATH-340: Fixed an error in BigFraction multiplication for large numerators that don't
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fit in a primitive int.
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o MATH-334: Added min/max getters for real vectors (not yet in the RealVector interface for
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compatibility purposes, but in the AbstractRealVector abstract class).
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o MATH-321: Singular Value Decomposition now computes either the compact SVD (using only
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positive singular values) or truncated SVD (using a user-specified maximal
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number of singular values).
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o MATH-300: Added support for multidimensional interpolation using the robust microsphere algorithm. Thanks to Gilles Sadowski.
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o MATH-287: Added support for weighted descriptive statistics. Thanks to Matthew Rowles.
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o Added normalizeArray method to MathUtils.
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Fixed Bugs:
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o MATH-360: Fix use of wrong variable in SmoothingBicubicSplineInterpolatorTest.testPreconditions()
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o MATH-335: Fraction.hashCode() implementation was not fully consistent with Fraction.equals().
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Changed hashCode() to use fields directly to agree with equals().
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o MATH-282: Resolved multiple problems leading to inaccuracy and/or failure to compute Normal,
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ChiSquare and Poisson probabilities, Erf and Gamma functions. Made Brent solver
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absolute accuracy configurable for all continuous distributions.
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o MATH-347: Fixed too stringent interval check in Brent solver: initial guess is now
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allowed to be at either interval end
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o MATH-358: Fixed an error in events handling in ODE solvers. In some rare cases, events
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occurring close to a step start were handled without truncating the step, making
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them appear as is they occurred close to the step end
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o Fixed a problem with getInterpolatedDerivatives returning zero derivatives when
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an ODE step handler is configured to not use interpolation. It now returns a
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constant but non-zero value consistent with at least one point inside the step
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o MATH-344: Fixed wrong return values when enpoints are roots in Brent solver with
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a user provided initial guess
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o MATH-343: Fixed a missing bracketing check of initial interval in Brent solver.
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o MATH-342: In SVD, the matrices passed to EigenDecomposition are now symmetric
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by construction (rather than simply by definition). In EigenDecomposition,
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once the tridiagonal form is obtained, the non-significant elements are
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set to 0.
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o MATH-333: A EigenDecompositionImpl simplified makes it possible to compute
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the SVD of a singular matrix (with the right number of elements in
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the diagonal matrix) or a matrix with singular value(s) of multiplicity
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greater than 1.
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o Fixed a spurious exception in EigenDecompositionImpl when a 3x3 block
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had two identical eigenvalues.
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o MATH-338: Fixed automatic step initialization in embedded Runge-Kutta integrators.
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The relative tolerance setting was never used, only the absolute tolerance
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was used. Thanks to Vincent Morand.
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o MATH-329: Fixed regression in Frequency.getPct(Object) introduced in 2.0. Cumulative
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percent was being returned for Object arguments in place of percent.
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o MATH-320: Fixed Singular Value Decomposition solving of singular systems.
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o MATH-326: Fixed a wrong implementation of the Linf norm in vectors. Thanks to Jake Mannix.
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o MATH-324: Fixed a convergence discrepancy with respect to theory in Gragg-Bulirsch-Stoer
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integrator. Thanks to Vincent Morand.
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o Fixed a wrong dimension check in SVD solver. Thanks to Dimitri Pourbaix.
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o MATH-313: Added composition features for real functions. Thanks to Jake Mannix.
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o MATH-312: Added mapping and iteration methods to vectors. Provided a default implementation
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for the numerous simple methods in the RealVectorInterface. Thanks to Jake Mannix.
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o MATH-322: Fixed an error in handling very close events in ODE integration.
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o MATH-305: Fixed an overflow error in MathUtils.distance that was causing KMeansPlusPlusClusterer
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to fail with a NullPointerException when component distances between points
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exceeded Integer.MAXVALUE. Thanks to Erik van Ingen.
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o MATH-318: Fixed an index computation error in eigen decomposition. Once again, kudos to Dimitri
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for debugging this. Thanks to Dimitri Pourbaix.
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o MATH-308: Fixed an ArrayIndexOutOfBoundsException in eigen decomposition. Kudos to Dimitri
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for debugging this, it was really difficult. Thanks to Dimitri Pourbaix.
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o MATH-309: Fixed parameter test in RandomDataImpl#nextExponential. The method now throws
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IllegalArgumentException for mean = 0. Thanks to Mikkel Meyer Andersen.
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o MATH-306: Removed dead code from Complex#divide. Thanks to Joerg Huber.
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o MATH-294: Fixed implementation of RandomDataImpl#nextPoisson by implementing an alternative
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algorithm for large means.
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o MATH-298: Fixed implementation of EmpiricalDistributionImpl#getUpperBounds to match
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interface contract. Added getGeneratorUpperBounds method to
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EmpiricalDistributionImpl providing previous behavior.
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o MATH-296: Fixed wrong results on Loess interpolation, also added a way to set weights
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for smoothing and to ignore zero weights for coefficients computation Thanks to Eugene Kirpichov.
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o MATH-293: Fixed a OutOfBoundException in simplex solver when some constraints are tight. Thanks to Benjamin McCann.
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o MATH-291: Fixed misleading number formats in error messages for adaptive
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stepsize integrators. Thanks to Sebb.
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o MATH-290: Fixed a NullPointerException in simplex solver when no solution is possible
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and some constraints are negative. Thanks to Benjamin McCann.
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o MATH-289: Removed an unused argument in a private method in simplex solver.
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o MATH-288: Fixed an error induced by entries set to 0 in simplex solver. Thanks to Benjamin McCann.
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o MATH-286: Fixed an error leading the simplex solver to compute the right solution
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but return another one. Thanks to Benjamin McCann.
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o MATH-283: Prevent infinite loops in multi-directional direct optimization method when
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the start point is exactly at the optimal point. Thanks to Michael Nischt.
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o MATH-297: Prevent possible zero divides on eigenvectors of indefinite matrices Thanks to Axel Kramer.
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Changes:
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o MATH-356: Added method to clear the list of observations in CurveFitter.
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o MATH-332: Added density functions to remaining continuous distributions (F, T, Weibull, Cauchy).
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As of Math 2.1, all continuous distributions implement density functions. The HasDensity
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interface has been deprecated and in version 3.0, density(double) will be added to the
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ContinuousDistribution interface. Thanks to Mikkel Meyer Andersen.
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o MATH-337: Changed equals() methods to use instanceof check rather than catching ClassCastException;
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this also allows some null checks to be omitted.
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o MATH-336: Removed unnecessary null checks in equals methods.
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o MATH-239: Added MathUtils methods to compute gcd and lcm for long arguments. Thanks to Christian Semrau.
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o MATH-287: Added support for weighted univariate statistics. Thanks to Matthew Rowles.
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o MATH-315: Added generationsEvolved property to GeneticAlgorithm to track the number of generations
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evolved by the evolve() method before reaching the StoppingCondition. Thanks to Mikkel Meyer Andersen.
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o MATH-311: Changed probability calculations for Binomial, Poisson, and Hypergeometric
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distributions to use Catherine Loader's saddle point approximations. Thanks to Nipun Jawalkar.
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For complete information on Commons Math, including instructions on how to submit bug reports,
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patches, or suggestions for improvement, see the Apache Commons Math website:
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http://commons.apache.org/math/
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