Changelog for hspray

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to the Haskell Package Versioning Policy.

0.1.0.0 - 2022-12-11

First release.

0.1.1.0 - 2022-12-12

• New functions toList, sprayTerms and bombieriSpray.

• New operation .^, to multiply a spray by an integer.

• Added some unit tests.

0.1.2.0 - 2023-02-24

New function derivSpray, to differentiate a spray.

0.1.3.0 - 2023-08-29

• Powers(..) is now exported.

• Completed the README to show how to deal with symbolic coefficients.

0.2.0.0 - 2024-03-14

• New functions prettySpray' and prettySprayXYZ.

• New function substituteSpray.

• New function sprayDivision, to perform the division of a spray by a list of sprays.

• New function groebner, to compute a Gröbner basis of a list of sprays.

• New function isSymmetricSpray, to check whether a spray is a symmetric polynomial.

• New function isPolynomialOf, to check whether a spray can be expressed as a polynomial of a given list of sprays.

0.2.1.0 - 2024-03-22

• New functions permuteVariables and swapVariables.

• New function resultant, to compute the resultant of two sprays.

• New function subresultants, to compute the subresultants of two sprays.

0.2.1.1 - 2024-03-25

• Improved the documentation.

• Flipped the order of appearance of the terms in the output of the prettySpray functions.

0.2.2.0 - 2024-03-26

• Fixed an error in esPolynomial, which resulted to a bug in isSymmetricSpray.

0.2.3.0 - 2024-03-28

• New unit tests.

• Fixed resultant and subresultants: the variables of the sprays they return were incorrect.

• New function gcdQX, to compute the greatest common divisor of two univariate sprays with rational coefficients.

0.2.4.0 - 2024-03-30

• Flipped the order of the arguments in permuteVariables and swapVariables.

• New function gcdSpray, to compute the greatest common divisor of two sprays with coefficients in a field.

• The function gcdQX has been removed since gcdSpray is more general.

• The function sprayDivision has been renamed to sprayDivisionRemainder.

• New function sprayDivision, returning the quotient and the remainder of the division of two sprays.

0.2.5.0 - 2024-04-02

• New function resultant' which computes the resultant of two sprays with coefficients in a field. Thus it is less general than the function resultant but it is more efficient.

• Fixed a small mistake in isSymmetricSpray and isPolynomialOf: these functions didn't deal with the constant term of the spray.

• New function psPolynomial which computes the power sum polynomials.

• A particular type of sprays, namely SymbolicSpray a, has been introduced. The coefficients of these sprays are ratios of univariate polynomials with a coefficients. There is a specialization SymbolicQSpray for the case when a is a type of rational numbers. The necessary instances have been defined and there is the function prettySymbolic(Q)Spray to display such sprays. There are also some functions to perform evaluation of such sprays.

0.2.6.0 - 2024-04-15

• New function collinearSprays which checks whether two sprays are collinear.

• The function isPolynomialOf threw an error when the number of variables in the spray to be tested was less than the number of variables in the list of sprays. That is me who programmed this error and this was wrong: for example, x = p1 - p2^*^p3 with p1 = x + y^*^z, p2 = y, and p3 = z.

• New functions to print sprays with numeric coefficients, such as prettyNumSpray and prettyQSpray.

• The functions prettySpray, prettySpray' and prettySpray'' have been changed.

• New functions to print symbolic sprays.

• Documentation and README have been improved.

0.2.7.0 - 2024-04-19

• Defined qlone, which is the same as lone but always returns a rational spray (a QSpray spray).

• The function sprayDivision ran into an infinite loop when the divisor was constant. This has been fixed.

• New function characteristicPolynomial, to compute the characteristic polynomial of a matrix.

• Gegenbauer polynomials. They have been implemented mainly to provide an illustration of the type Spray (Spray a) in README.

• New function evalSpraySpray, to evaluate the spray coefficients of a Spray (Spray a) spray, thereby yielding a Spray a spray.

• New type RatioOfSprays a, whose objects represent ratios of polynomials represented by two Spray a objects. Thus the type Spray (RatioOfSprays a) allows more possibilities than the type SymbolicSpray a because it is not restricted to univariate fractions of polynomials, and obviously it also allows more possibilities than the type Spray (Spray a). Instances and arithmetic operations for these ratios of sprays have been defined. The result of an arithmetic operation always is an irreducible fraction. See README for examples.

• Jacobi polynomials. They have been implemented mainly to experiment the type Spray (RatioOfSprays a). By the way, this type has been named ParametricSpray a, but this is possibly temporary.

• The class HasVariables a has been introduced in order to have some functions which apply to both Spray a objects and RatioOfSprays a objects.

• The function derivSpray no longer exists. To get a derivative of a spray, use the derivative function, which is also applicable to a ratio of sprays (this is a method of the class HasVariables).

• A spray with coefficients in a field can now be divided by a scalar by using the /> operator. This operator can also be used to divide a ratio of sprays (with coefficients in a field) by a scalar.

0.3.0.0 - 2024-04-21

• The type SymbolicSpray a has been renamed to OneParameterSpray a, and all functions names which contained the string Symbolic have been changed by replacing Symbolic with OnePerameter.

• The class HasVariables, which is instantiated for Spray and RatioOfSprays, has a new method changeVariables allowing to perform polynomial transformations of the variables of a spray and of a ratio of sprays. For sprays, this is the same as the composeSpray function.

• The class HasVariables is now also instantiated for RatioOfPolynomials.

• The type alias ParametricSpray a = Spray (RatioOfSprays a) has been kept and the type alias SimpleParametricSpray a = Spray (Spray a) has been introduced. We say that a Spray b spray is parametric when b has the HasVariables instance. So this applies to a ParametricSpray a spray, to a SimpleParametricSpray a spray, and also to a OneParameterSpray a spray (recall that OneParameterSpray a = Spray (RatioOfPolynomials a)).

• Functions to print ParametricSpray sprays and SimpleParametricSpray sprays.

• Function numberOfParameters, returning the number of parameters of a parametric spray, that is to say the number of variables occurring in the coefficients of this spray.

• Function changeParameters, to perform polynomial transformations of the parameters of a parametric spray.

• Function substituteParameters, to replace the parameters of a parametric spray with some values. For a SimpleParametricSpray spray, this function is the same as evalSpraySpray(which will probably disappear in the future).

• Function evalParametricSpray, to replace the variables of a parametric spray with some values.

0.4.0.0 - 2024-04-27

• The efficiency of the arithmetic on the RatioOfSprays fractions of polynomials has been greatly improved for the univariate case. According to some benchmarks on the Jack polynomials, the ParametricSpray sprays with only one parameter are now more efficient than the OneParameterSpray sprays.

• For this reason, the Jack polynomials with a symbolic Jack parameter, implemented in the 'jackpolynomials' package, are represented by ParametricSpray sprays in a new version of the package, while there were previously represented by OneParameterSpray sprays.

• Slight improvements of the code in general.

• Function lone' to construct monomials like x_n^p more efficiently than lone n ^**^ p.

• Function monomial to construct monomials like x_1^4.x_3^7.

0.5.0.0 - 2024-05-01

• The class HasVariables has been renamed to FunctionLike, and the arithmetic operations for sprays (^+^, ^-^, ^*^, ^**^, *^) have been moved to this class. Therefore it is now possible to apply these operations to the ratios of sprays. Moreover, there are two new operators in this class, (+>) and (<+), which allow to add a constant to an object of this class. For example, x +> spray gives the same result as constantSpray x ^+^ spray but is more efficient.

• There was an error in gcdSpray.

• There was a small mistake in collinearSprays.

• The functions changeParameters and changeVariables did not remove the possibly null terms of their result.

• The function groebner has been renamed to groebnerBasis.

• Function isHomogeneousSpray, to check whether a spray defines a homogeneous polynomial.

0.5.1.0 - 2024-05-03

• An error in an internal function resulted in an error in groebnerBasis. It has been fixed.

• A limit on the number of elements of a Gröbner basis has been set in the algorithm performed by groebnerBasis. When this limit is attained, an error is thrown. The reason of this limit is that I encountered an example of a large Gröbner basis and the algorithm took a quite long time.

• There was an error in esPolynomial.

• The FunctionLike class provides two new functions: involvesVariable, to check whether a variable is involved in a function-like object (a spray or a ratio of sprays), and dropVariables, to drop a given number of leading variables in a function-like object. The dropVariables functions is very unsafe: if a variable is dropped while it is involved, the result can be an invalid function-like object.

0.5.2.0 - 2024-05-05

• Function polynomialSubresultants, to compute the polynomial subresultants of two sprays (while the subresultants function computes the principal subresultants).

• Function sturmHabichtSequence, to compute the Sturm-Habicht sequence of a spray.

• Function principalSturmHabichtSequence, to compute the principal Sturm-Habicht sequence of a spray.

• Functions numberOfRealRoots, numberOfRealRootsInOpenInterval and numberOfRealRootsInClosedInterval, to compute the total number of real roots of a suitable univariate spray or its number of real roots in a given interval. This can be very slow if the degree of the spray is not small.

0.5.3.0 - 2024-06-03

• Now the denominator of a RatioOfSprays is always monic, i.e. it is a polynomial whose leading coefficient is 1.