This page lists the hard and optional dependencies of SymPy.
There are several packages that, when installed, can enable certain additional SymPy functionality. Most users and contributors will not need to install any of the packages mentioned below (except for the hard dependencies), unless they intend to use or contribute to the parts of SymPy that can use those packages.
Every dependency listed below can be installed with conda via
conda-forge, and most can also be installed with
This page does not list packages which themselves depend on SymPy, only those packages that SymPy depends on. An incomplete list of packages that depend on SymPy can be found on the main SymPy webpage, and a more complete list can be found on GitHub or libraries.io.
SymPy only has one hard dependency, which is required for it to work: mpmath.
SymPy cannot function without mpmath and will fail to import if it is not installed. If you get an error like
ImportError: SymPy now depends on mpmath as an external library. See https://docs.sympy.org/latest/install.html#mpmath for more information.
this means that you did not install mpmath correctly. This page explains how to install it.
Most methods of installing SymPy, such as the ones outlined in the installation guide, will install mpmath automatically. You typically only need to install mpmath manually if you did not actually install SymPy, e.g., if you are developing directly on SymPy in the git repository.
These dependencies are not required to use SymPy. The vast majority of SymPy functions do not require them, however, a few functions such as plotting and automatic wrapping of code generated functions require additional dependencies to function.
Additionally, as a contributor, when running the SymPy tests, some tests will be skipped if a dependency they require is not installed. The GitHub Actions CI which is run on every SymPy pull request will automatically install these dependencies in the “optional-dependencies” build, but you may wish to install them locally if you are working on a part of SymPy that uses them.
Recommended Optional Dependencies¶
These dependencies are not required for SymPy to function, but it is recommended that all users install them if they can, as they will improve the general performance of SymPy.
gmpy2: gmpy2 is a Python wrapper for the GMP multiple-precision library. It provides large integers that are faster than the built-in Python
int. When gmpy2 is installed, it is used automatically by certain core functions that operate on integers, such as the polys. See Reference docs for the Poly Domains for more details. SymPy uses
gmpy2automatically when it is installed. No further action is required to enable it.
The polys themselves are used by many parts of SymPy, such as the integration algorithms, simplification algorithms like
factor(), the matrices, and some parts of the core. Thus, installing
gmpy2can speed up many parts of SymPy. It is not a required dependency of SymPy because it makes use of a non-Python library (GMP), which is also non-BSD licensed. However, we recommended all users who are able to to install
gmpy2to get a better SymPy experience.
SymPy is designed to be used both interactively and as a library. When used interactively, SymPy is able to interface with IPython and Jupyter notebooks.
isympycommand will automatically start IPython if it is installed. In addition to the usual benefits of using IPython, this enables interactive plotting with matplotlib. Also some flags such as
auto_int_to_Integerwill only work in IPython.
IPythonpackage is required to run some of the tests in sympy/interactive.
preview() function automatically converts SymPy expressions into
images rendered with LaTeX.
preview() can either save the image to a file or
show it with a viewer.
Several functions in the
sympy.parsing submodule require external
dependencies to function. Note that not all parsers require external modules
at this time. The Python (
mathematica()), and Maxima (
parse_maxima()) parsers do not
require any external dependencies.
antlr-python-runtime: Antlr is used for the
LaTeX parserand Autolev parsers. They both require the Antlr Python runtime to be installed. The package for this is called
antlr4-python-runtimewith conda and
antlr4-python3-runtimewith pip). Also be aware that the version of the Antlr Python runtime must match the version that was used to compile the LaTeX and Autolev parsers (4.7).
Clang Python Bindings: The C parser (
sympy.parsing.c.parse_c) requires the Clang Python bindings. The package for this is called
python-clangwith conda and
lfortran: The Fortran parser (in
sympy.parsing.fortran) requires LFortran.
satisfiable() function includes a pure Python implementation of
the DPLL satisfiability algorithm. But it can optionally use faster C SAT
solvers if they are installed. Note that
satisfiable() is also used by
pycosat: Pycosat is used automatically if it is installed. The use of pycosat can be forced by using
sympy.plotting.plot module makes heavy use of external plotting
libraries to render plots. The primarily plotting module that is supported is
lambdify() is a function that converts SymPy expressions into functions
that can be evaluated numerically using various libraries as backends.
lambdify is the primary vehicle by which users interface between SymPy and
these libraries. It is the standard way to convert a symbolic SymPy expression
into an evaluable numeric function.
lambdify can interface with any external library if the user
passes in an appropriate namespace dictionary as the third argument, but by
lambdify is aware of several popular numeric Python libraries.
These libraries are enabled as backends in
lambdify with build-in
translations to convert SymPy expressions into the appropriate functions for
NumPy: By default, if it is installed,
lambdifycreates functions using NumPy (if NumPy is not installed,
lambdifyproduces functions using the standard library math module, although this behavior is primarily provided for backwards compatibility).
CuPy: CuPy is a library that provides a NumPy compatible interface for CUDA GPUs.
lambdifycan produce CuPy compatible functions using
TensorFlow: TensorFlow is a popular machine learning library.
lambdifycan produce TensorFlow compatible functions using
NumExpr: NumExpr is a fast numerical expression evaluator for NumPy.
lambdifycan produce NumExpr compatible functions using
lambdifycan also produce mpmath compatible functions. Note that mpmath is already a required dependency of SymPy. This functionality is useful for converting a SymPy expression to a function for use with pure mpmath.
SymPy can generate code for a large number of languages by converting SymPy expressions into valid code for those languages. It also has functionality for some languages to automatically compile and run the code.
Note that the dependencies below are not a list of supported languages
that SymPy can generate code for. Rather it is a list of packages that SymPy
can interface with in some way. For most languages that SymPy supports code
generation, it simply generates a string representing the code for that
language, so no dependency on that language is required to use the code
generation functionality. A dependency is typically only required for features
that automatically take the generated code and compile it to a function that
can be used within Python. Note that
lambdify() is a special case of
this, but its dependencies are listed above.
Most code printers generate Python strings, and therefore do not require the given library or language compiler as a dependency. However, a few code printers generate Python functions instead of strings:
sympy.printing.aesaracodemodule contains functions to convert SymPy expressions into a functions using the Aeseara (previously Theano) library. The Aesara code generation functions return Aesara graph objects.
sympy.printing.llvmjitcodemodule supports generating LLVM Jit from a SymPy expression. The functions make use of llvmlite, a Python wrapper around LLVM. The
llvm_callable()function generates callable functions.
sympy.printing.tensorflowmodule supports generating functions using the TensorFlow, a popular machine learning library. Unlike the above two examples,
tensorflow_code()function does generate Python strings. However,
tensorflowis imported if available in order to automatically detect the TensorFlow version. If it is not installed, the
tensorflow_code()function assumes the latest supported version of TensorFlow.
Wurlitzer: Wurlitzer is a Python package that allows capturing output from C extensions. It is used by some of the tests in the
sympy.codegensubmodule. It is only used by the test suite. It is not used by any end-user functionality. If it is not installed, some tests will be skipped.
Cython: Cython is also used in some of the
sympy.codegentests to compile some examples.
Compilers: The various compilers mentioned above are used in some of the codegen and autowrap tests if they are installed.
sympy.stats.sample() function uses an external library to produce
samples from the given distribution. At least one of the following libraries
is required to use the sampling functionality of
Optional SymEngine Backend¶
python-symengine: SymEngine is a fast symbolic manipulation library, written in C++. The SymEngine Python bindings may be used as an optional backend for SymPy core. To do this, first install the SymEngine Python bindings (with
pip install symengineor
conda install -c conda-forge python-symengine) and run SymPy with the
Presently, the SymEngine backend is only used by the sympy.physics.mechanics and sympy.liealgebras modules, although you can also interface with SymPy’s SymEngine backend directly by importing things from
>>> from sympy.core.backend import Symbol >>> # This will create a SymEngine Symbol object if the USE_SYMENGINE >>> # environment variable is configured. Otherwise it will be an ordinary >>> # SymPy Symbol object. >>> x = Symbol('x')
SymEngine backend support is still experimental, so certain SymPy functions may not work correctly when it is enabled.
Experimental Rubi Integrator¶
MatchPy: MatchPy is a library for doing pattern matching. It is used in the experimental sympy.integrals.rubi module, but presently, it is not used anywhere else in SymPy. SymPy and MatchPy are able to interface with each other.
Sage is an open source mathematics software that incorporates a large number of open source mathematics libraries. SymPy is one of the libraries used by Sage.
Most of the code that interfaces between SymPy and Sage is in Sage itself, but
_sage_ methods in SymPy that do some very basic setting up of the
Sage/SymPy wrappers. These methods should typically only be called by Sage
Typical development on SymPy does not require any additional dependencies beyond Python and mpmath.
Getting the Source Code¶
Running the Tests¶
The base SymPy tests do not require any additional dependencies, however most
of the above dependencies may be required for some tests to run. Tests that
depend on optional dependencies should be skipped when they are not installed,
either by using the
sympy.testing.pytest.skip() function or by setting
skip = True to skip the entire test file. Optional modules in tests and SymPy
library code should be imported with
pytest: Pytest is not a required dependency for the SymPy test suite. SymPy has its own test runner, which can be accessed via the
bin/testscript in the SymPy source directory or the
However, if you prefer to use pytest, you can use it to run the tests instead of the SymPy test runner. Tests in SymPy should use the wrappers in
sympy.testing.pytestinstead of using pytest functions directly.
Cloudpickle: The cloudpickle package can be used to more effectively pickle SymPy objects than the built-in Python pickle. Some tests in
sympy.utilities.tests.test_pickling.pydepend on cloudpickle to run. It is not otherwise required for any SymPy function.
Building the Documentation¶
Building the documentation requires several additional dependencies. This page outlines these dependencies and how to install them. It is only necessary to install these dependencies if you are contributing documentation to SymPy and want to check that the HTML or PDF documentation renders correctly. If you only want to view the documentation for the development version of SymPy, development builds of the docs are hosted online at https://docs.sympy.org/dev/index.html.
Running the Benchmarks¶
Note that the benchmarks are also run automatically on the GitHub Actions CI, so it is generally not necessary to run them yourself as a contributor unless you want to reproduce the benchmarks results on your computer or add a new benchmark to the suite.
asv: Airspeed Velocity is the package used for running the benchmarks. Note that the package name that you install is called