SymPy Changelog

What's new in SymPy 1.0

Mar 9, 2016

MAJOR CHANGES:mpmath is now a hard external dependency for SymPy. sympy.mpmath will no longer work (use import mpmath). See http://docs.sympy.org/latest/install.html#mpmath for more information on how to install mpmath.
The galgebra Geometric Algebra module has been removed. The module is now maintained separately at https://github.com/brombo/galgebra.
The new solveset function is a planned replacement for solve. solve is not yet deprecated, since solveset hasn't yet fully replicated all the functionality of solve. solveset offers an improved interface to solve. See http://docs.sympy.org/latest/modules/solvers/solveset.html for more information on solveset vs. solve.
This will be the last version of SymPy to support Python 2.6 and 3.2. Both of these Python versions have reached end-of-life. Support for other Python versions will continue at least until they have reached end-of-life.
NEW FEATURES:
The module sympy.series.ring_series has been updated. New methods for series inversion, expansion of hyperbolic and inverse functions, etc have been added. PR #9262
New module sympy.series.sequences for generating finite/infinite lazily evaluated lists. [PR #9435]
The string representation function srepr() now displays the assumptions used to create a Symbol. For example, srepr(Symbol('x', real=True)) now returns the string "Symbol('x', real=True)" instead of merely "Symbol('x')".
not_empty_in function added to util.py in calculus module which finds the domain for which the FiniteSet is not-empty for a given Union of Sets. [PR #9779]
A new and fast method rs_series has been added for calculating series expansions. It can handle multivariate Puiseux series with symbolic coefficients. It is especially optimized for large series, with speedup over the older series method being in the range 20-1000 times. PR #9775
Complex Sets has been added here: sympy.sets.fancysets, use S.Complexes for singleton ComplexRegion class. PR #9463
GeometryEntity now subclasses from sets.Set, so sets.Intersection and sets.Union can be used with GeometryEntitys. For example Intersection(Line((-1,-1),(1,1)), Line((-1,1), (1,-1))) == FiniteSet(Point2D(0,0)).
New module sympy.series.fourier for computing fourier sine/cosine series. [PR #9523]
Linsolve: General Linear System Solver in sympy.solvers.solveset, use linsolve() for solving all types of linear systems. PR #9438
New assumption system is now able to read the assumptions set over Symbol object. A new handler system has been added as sympy.assumptions.satask which uses satisfiable to answer queries related to assumptions. In case the legacy ask doesn't know the answer, it falls back on satask.
New module sympy.series.formal for computing formal power series. [PR #9639]
New set class ConditionSet was implemented. [PR #9696]
Differential calculus Methods, like is_increasing, is_monotonic, etc were implemented in sympy.calculus.singularities in [PR #9820]
New module sympy.series.limitseq for finding limits of terms containing sequences. [PR #9836]
New module sympy/polys/subresultants_qq_zz.py :: contains various functions for computing Euclidean, Sturmian and (modified) subresultant polynomial remainder sequences in Q[x] or Z[x]. All methods are based on the recently discovered theorem by Pell and Gordon of 1917 and an extension/generalization of it of 2015. [PR #10374]
MINOR CHANGES:
limit(sin(x), x, oo) now returns AccumulationBound object instead of un-evaluated sin(oo). Implemented in [PR #10051].
Point is now an n-dimensional point and subclassed to Point2D and Poin3D where appropriate. Point is also now enumerable and can be indexed (e.g., x=Point(1,2,3); x[0])
roots_cubic will no longer raise an error when the sign of certain expressions is unknown. It will return a generally valid solution instead.
Relational.canonical will put a Relational into canonical form which is useful for testing whether two Relationals are trivially the same.
Relational.reversed gives the Relational with lhs and rhs reversed and the symbol updated accordingly (e.g. (x < 1).reversed -> 1 > x
Simplification of Relationals will, if the threshold for simplification is met, also return the Relational in canonical form. One of the criteria of being in canonical form is that the Number will be on the rhs. This makes writing tests a little easier so S(1) > x can be entered as 1 > x or x < 1 (the former being turned into the latter by Python).
boolalg functions And, Or, Implies, Xor, Equivalent are aware of Relational complements and trivial equalities, so, for example, And(x=1) will reduce to False while And(S(1)>x,x

New in SymPy 1.0 RC 1 (Feb 29, 2016)

New in SymPy 0.7.6.1 (Sep 5, 2015)

New in SymPy 0.7.6 (Nov 28, 2014)

MAJOR CHANGES:
New module calculus.finite_diff for generating finite difference formulae approximating derivatives of arbitrary order on arbitrarily spaced grids.
New module physics.optics for symbolic computations related to optics.
geometry module now supports 3D geometry.
Support for series expansions at a point other then 0 or oo. See PR #2427.
Rules for the intersection of integer ImageSets were added. See PR #7587. We can now do things like {2⋅m | m ∊ ℤ} ∩ {3⋅n | n ∊ ℤ} = {6⋅t | t ∊ ℤ} and {2⋅m | m ∊ ℤ} ∩ {2⋅n + 1 | n ∊ ℤ} = ∅
dsolve module now supports system of ODEs including linear system of ODEs of 1st order for 2 and 3 equations and of 2nd order for 2 equations. It also supports homogeneous linear system of n equations.
New support for continued fractions, including iterators for partial quotients and convergents, and reducing a continued fraction to a Rational or a quadratic irrational.
Support for Egyptian fraction expansions, using several different algorithms.
Addition of generalized linearization methods to physics.mechanics.
Use an LRU cache by default instead of an unbounded one. See PR #7464. Control cache size by the environment variable SYMPY_CACHE_SIZE (default is 500). SYMPY_CACHE_SIZE=None restores the unbounded cache.
Added fastcache as an optional dependency. Requires v0.4 or newer. Control via SYMPY_CACHE_SIZE. May result in significant speedup. See PR #7737.
New experimental module physics.unitsystems for computation with dimensions, units and quantities gathered into systems. This opens the way to dimensional analysis and better quantity calculus. The old module physics.units will stay available until the new one reaches a mature state. See PR #2628.
New Complement class to represent relative complements of two sets. See Pr #7462.
New trigonometric functions (asec, acsc), many enhancements for other trigonometric functions (PR #7500).
New Contains class to represent the relation "is an element of" (see PR #7989).
The code generation tools (code printers, codegen, autowrap, and ufuncify) have been updated to support a wider variety of constructs, and do so in a more robust way. Major changes include added support for matrices as inputs/outputs, and more robust handling of conditional (Piecewise) statements.
ufuncify now uses a backend that generates actual numpy.ufuncs by default through the use of the numpy C api. This allows broadcasting on all arguments. The previous cython and f2py backends are still accessible through the use of the backend kwarg.
CodeGen now generates code for Octave and Matlab from SymPy expressions. This is supported by a new CodePrinter with interface octave_code. For example octave_code(Matrix([[x**2, sin(pi*x*y), ceiling(x)]])) gives the string [x.^2 sin(pi*x.*y) ceil(x)].
New general 3D vector package at sympy.vector. This package provides a 3D vector object with the Del, gradient, divergence, curl, and operators. It supports arbitrary rotations of Cartesian coordinate systems and arbitrary locations of points.
BACKWARDS COMPATIBILITY BREAKS AND DEPRECATIONS:
All usage of inequalities (>, >=,

New in SymPy 0.7.4.1 (Feb 14, 2014)

New in SymPy 0.7.2 (Oct 17, 2012)

Python 3 support:
SymPy now supports Python 3. The officially supported versions are 3.2 and 3.3, but 3.1 should also work in a pinch. The Python 3-compatible tarballs will be provided separately, but it is also possible to download Python 2 code and convert it manually, via the bin/use2to3 utility. See the README for more
PyPy support:
All SymPy tests pass in recent nightlies of PyPy, and so it should have full support as of the next version after 1.9.
Combinatorics:
A new module called Combinatorics was added which is the result of a successful GSoC project. It attempts to replicate the functionality of Combinatorica and currently has full featured support for Permutations, Subsets, Gray codes and Prufer codes.
In another GSoC project, facilities from computational group theory were added to the combinatorics module, mainly following the book "Handbook of computational group theory". Currently only permutation groups are supported. The main functionalities are: basic properties (orbits, stabilizers, random elements...), the Schreier-Sims algorithm (three implementations, in increasing speed: with Jerrum's filter, incremental, and randomized (Monte Carlo)), backtrack searching for subgroups with certain properties.
Definite Integration:
A new module called meijerint was added, which is also the result of a successful GSoC project. It implements a heuristic algorithm for (mainly) definite integration, similar to the one used in Mathematica. The code is automatically called by the standard integrate() function. This new algorithm allows computation of important integral transforms in many interesting cases, so helper functions for Laplace, Fourier and Mellin transforms were added as well.
Random Variables:
A new module called stats was added. This introduces a RandomSymbol type which can be used to model uncertainty in expressions.
Matrix Expressions:
A new matrix submodule named expressions was added. This introduces a MatrixSymbol type which can be used to describe a matrix without explicitly stating its entries. A new family of expression types were also added: Transpose, Inverse, Trace, and BlockMatrix. ImmutableMatrix was added so that explicitly defined matrices could interact with other SymPy expressions.
Sets:
A number of new sets were added including atomic sets like FiniteSet, Reals, Naturals, Integers, UniversalSet as well as compound sets like ProductSet and TransformationSet. Using these building blocks it is possible to build up a great variety of interesting sets.
Classical Mechanics:
A physics submodule named machanics was added which assists in formation of equations of motion for constrained multi-body systems. It is the result of 3 GSoC projects. Some nontrivial systems can be solved, and examples are provided.
Quantum Mechanics:
Density operator module has been added. The operator can be initialized with generic Kets or Qubits. The Density operator can also work with TensorProducts as arguments. Global methods are also added that compute entropy and fidelity of states. Trace and partial-trace operations can also be performed on these density operators.
To enable partial trace operations a Tr module has been added to the core library. While the functionality should remain same, this module is likely to be relocated to an alternate folder in the future. One can currently also use sympy.core.Tr to work on general trace operations, but this module is what is needed to work on trace and partial-trace operations on any sympy.physics.quantum objects.
The Density operators, Tr and Partial trace functionality was implemented as part of student participation in GSoC 2012
Expanded angular momentum to include coupled-basis states and product-basis states. Operators can also be treated as acting on the coupled basis (default behavior) or on one component of the tensor product states. The methods for coupling and uncoupling these states can work on an arbitrary number of states. Representing, rewriting and applying states and operators between bases has been improved.
Commutative Algebra:
A new module agca was started which seeks to support computations in commutative algebra (and eventually algebraic geometry) in the style of Macaulay2 and Singular. Currently there is support for computing Groebner bases of modules over a (generalized) polynomial ring over a field. Based on this, there are algorithms for various standard problems in commutative algebra, e.g., computing intersections of submodules, equality tests in quotient rings, etc....
Plotting Module:
A new plotting module has been added which uses Matplotlib as its back-end. The plotting module has functions to plot the following
2D line plots
2D parametric plots.
2D implicit and region plots.
3D surface plots.
3D parametric surface plots.
3D parametric line plots.
Differential Geometry:
Thanks to a GSoC project the beginning of a new module covering the theory of differential geometry was started. It can be imported with sympy.diffgeom. It is based on "Functional Differential Geometry" by Sussman and Wisdom. Currently implemented are scalar, vector and form fields over manifolds as well as covariant and other derivatives.
Backwards compatibility breaks:
The KroneckerDelta class was moved from sympy/physics/quantum/kronecker.py to sympy/functions/special/tensor_functions.py.
Merged the KroneckerDelta class in sympy/physics/secondquant.py with the class above.
The Dij class in sympy/functions/special/tensor_functions.py was replaced with KroneckerDelta.
The errors raised for invalid float calls on SymPy objects were changed in order to emulate more closely the errors raised by the standard library. The __float__ and __complex__ methods of Expr are concerned with that change.
The solve() function returns empty lists instead of None objects if no solutions were found. Idiomatic code of the form sol = solve(...); if sol:... will not be affected by this change.
Piecewise no longer accepts a Set or Interval as a condition. One should explicitly specify a variable using Set().contains(x) to obtain a valid conditional.
The statistics module has been deprecated in favor of the new stats module.
sympy/galgebra/GA.py:
set_main() is no longer needed
make_symbols() is deprecated (use sympy.symbols() instead)
the symbols used in this package are no longer broadcast to the main program
The classes for Infinity, NegativeInfinity, and NaN no longer subclass from Rational. Creating a Rational with 0 in the denominator will still return one of these classes, however.
Other Changes:
A new module gaussopt was added supporting the most basic constructions from Gaussian optics (ray tracing matrices, geometric rays and Gaussian beams).
New classes were added to represent the following special functions: classical and generalized exponential integrals (Ei, expint), trigonometric (Si, Ci) and hyperbolic integrals (Shi, Chi), the polylogarithm (polylog) and the Lerch transcendent (lerchphi). In addition to providing all the standard sympy functionality (differentiation, numerical evaluation, rewriting ...), they are supported by both the new meijerint module and the existing hypergeometric function simplification module.
An ImmutableMatrix class was created. It has the same interface and functionality of the old Matrix but is immutable and inherits from Basic.
A new function in geometry.util named centroid was added which will calculate the centroid of a collection of geometric entities. And the polygon module now allows triangles to be instantiated from combinations of side lengths and angles (using keywords sss, asa, sas) and defines utility functions to convert between degrees and radians.
In ntheory.modular there is a function (solve_congruence) to solve congruences such as "What number is 2 mod 3, 3 mod 5 and 2 mod 7?"
A utility function named find_unit has been added to physcis.units that allows one to find units that match a given pattern or contain a given unit.
There have been some additions and modifications to Expr's methods:
Although the problem of proving that two expressions are equal is in general a difficult one (since whatever algorithm is used, there will always be an expression that will slip through the algorithm) the new method of Expr named equals will do its best to answer whether A equals B: A.equals(B) might given True, False or None.
coeff now supports a third argument n (which comes 2nd now, instead of right). This n is used to indicate the exponent on x which one seeks: (x**2 + 3*x + 4).coeff(x, 1) -> 3. This makes it possible to extract the constant term from a polynomial: (x**2 + 3*x + 4).coeff(x, 0) -> 4.
The method round has been added to round a SymPy expression to a given a number of decimal places (to the left or right of the decimal point).
divmod is now supported for all SymPy numbers.
In the simplify module, the algorithms for denesting of radicals (sqrtdenest) and simplifying gamma functions (in combsimp) has been significantly improved.
The mathematica-similar TableForm function has been added to the printing.tableform module so one can easily generate tables with headings.
In addition to the more noticeable changes listed above, there have been numerous smaller additions, improvements and bug fixes in the commits in this release. See the git log for a full list of all changes. The command git log sympy-0.7.1..sympy-0.7.2 will show all commits made between this release and the last. You can also see the issues closed since the last release here.
The expand API has been updated. expand() now officially supports arbitrary _eval_expand_hint() methods on custom objects. _eval_expand_hint() methods are now only responsible for expanding the top-level expression. All deep=True related logic happens in expand() itself. See the docstring of expand() for more information and an example.
Two options were added to isympy to aid in interactive usage. isympy -a automatically creates symbols, so that typing something like a will give Symbol('a'), even if you never typed a = Symbol('a') or var('a'). isympy -i automatically wraps integer literals with Integer, so that 1/2 will give Rational(1, 2) instead of 0.5. isympy -I is the same as isympy -a -i. isympy -I makes isympy act much more like a traditional interactive computer algebra system. These both require IPython.
The official documentation at http://docs.sympy.org now includes an extension that automatically hooks the documentation examples in to SymPy Live.

SymPy Changelog

What's new in SymPy 1.0

New in SymPy 1.0 RC 1 (Feb 29, 2016)

New in SymPy 0.7.6.1 (Sep 5, 2015)

New in SymPy 0.7.6 (Nov 28, 2014)

New in SymPy 0.7.4.1 (Feb 14, 2014)

New in SymPy 0.7.2 (Oct 17, 2012)

New in SymPy 0.7.1 (Jul 31, 2011)

New in SymPy 0.7.0 (Jul 1, 2011)

New in SymPy 0.6.7 (Mar 24, 2010)

New in SymPy 0.6.5 (Jul 17, 2009)

New in SymPy 0.6.4 (Apr 8, 2009)

New in SymPy 0.6.3 (Nov 20, 2008)

New in SymPy 0.6.2 (Oct 30, 2008)