CSymPy is a standalone fast C++ symbolic manipulation library. Optional thin Python wrappers allow easy usage from Python and integration with SymPy.

All files are licensed under MIT license, see the LICENSE for more information. The src/teuchos directory is licensed under the Trilinos BSD license (see the LICENSE file).

Install prerequisites. For Debian based systems (Ubuntu etc.):

apt-get install cmake libgmp-dev

For RPM based systems (Fedora etc.):

yum install cmake gmp-devel

Install csympy:

cmake .
make

This will configure and build CSymPy in the default Release mode with all code and compiler optimizations on.

Run tests:

ctest

The optional Python wrappers can be turned on by

cmake -DWITH_PYTHON=yes .
make

Use CSymPy from Python as follows:

>>> from csympy import var
>>> var("x y z")
(x, y, z)
>>> e = (x+y+z)**2
>>> e.expand()
2x*z + x^2 + 2y*x + 2y*z + z^2 + y^2

You can read Python tests in csympy/tests to see what features are implemented. Supported versions of Python are: 2.6, 2.7, 3.2, 3.3. You need Cython >= 0.19.1 in order to compile the wrappers. CMake will report at configure time if the Cython version is too old.

The Travis-CI checks the code in both Release and Debug mode with all possible checks, so just sending a GitHub pull request is enough and you can use any mode you want to develop it. However, the best way to develop CSymPy is to use the Debug mode, turn assertions on and turn BFD support on (prints very nice stacktraces on exceptions, segfaults or assert errors):

cmake -DCMAKE_BUILD_TYPE=Debug \
    -DWITH_CSYMPY_ASSERT=yes \
    -DWITH_BFD=yes \
    .

To make WITH_BFD=yes work, you need to install binutils-dev first, otherwise you will get a CMake error during configuring. For Debian based systems (Ubuntu etc.)

apt-get install binutils-dev

For RPM based systems (Fedora etc.)

yum install binutils-devel

Here are all the CMake options that you can use to configure the build, with their default values indicated below:

cmake -DCMAKE_INSTALL_PREFIX:PATH="/usr/local" \  # Installation prefix
    -DCMAKE_BUILD_TYPE:STRING="Release" \         # Type of build, one of: Debug or Release
    -DWITH_BFD:BOOL=OFF \                         # Install with BFD library (requires binutils-dev)
    -DWITH_PYTHON:BOOL=OFF \                      # Build Python wrappers
    -DWITH_CSYMPY_ASSERT:BOOL=OFF \               # Test all CSYMPY_ASSERT statements in the code
    -DWITH_CSYMPY_RCP:BOOL=ON \                   # Use our faster special implementation of RCP
    .

CMake prints the value of its options at the end of the run. If you want to use a different compiler, do:

CXX=clang cmake .

and check that CMake picked it up.

Please follow the C++ Style Guide when developing.

The design decisions are documented in Design.

Memory management is handled by RCP (reference counted pointers) from Trilinos (module Teuchos). We have copied the relevant files into src/teuchos, so no external dependency is needed. Brief code snippets of the most frequent operations are given in our C++ Style Guide, this is useful to consult if you are unsure about the syntax. In order to understand how it works under the hood, read Teuchos::RCP Beginner's Guide (pdf). Finally, more thorough exposition is given in Teuchos C++ Memory Management Classes, Idioms, and Related Topics --- The Complete Reference (pdf).

Teuchos' RCP implements reference counting of objects, exactly like Python works. When an object runs out of scope, its reference count is decreased. When it is copied, its reference count is increased. When reference count goes to zero, it is deallocated. This all happens automatically, so as long as our C++ Style Guide is followed, things just work.

When CMAKE_BUILD_TYPE=Debug is set in our CMake (the default), then Teuchos is compiled with debugging support, which means that as long as you follow our C++ Style Guide, the C++ code should never segfault (since you never access raw pointers that could segfault and Teuchos raises nice exception with full stacktrace if there is any problem, very similar to Python). Use this mode when developing.

When CMAKE_BUILD_TYPE=Release, then Teuchos is compiled without debugging support, which means that all pointer operations become either as fast as raw pointers, or very close. As such, there is pretty much zero overhead. However, in this mode, the program can segfault if you access memory incorrectly. This segfault however would be prevented if CMAKE_BUILD_TYPE=Debug, so always use the Debug build to test your code, only when all tests pass you can enable Release mode.

The Trilinos RCP pointers as described above are only used when WITH_CSYMPY_RCP=OFF is set in CMake. The default option is WITH_CSYMPY_RCP=ON, which uses our own implementation of RCP (see src/csympy_rcp.h). Our implementation is faster, but it only implements a subset of all the functinoality and it requires all our objects to have a refcount_ variable. Otherwise the usage of our RCP is identical to Teuchos::RCP, and Travis-CI tests both implementations of RCP to make sure the code works with both.