Fast and lightweight set for unsigned 32 bits integers.
Project description
An efficient and light-weight ordered set of 32 bits integers. This is a Python wrapper for the C library CRoaring.
The wrapping used to be done with Ctypes. We recently switched to Cython for the following reasons:
Much better performances for short function calls (e.g. addition/deletion of a single element).
Easier installation, no need to install manually the C library, it is now distributed with PyRoaring.
Extensibility, it will be easier to write efficient codes with Cython (e.g. some data structures based on roaring bitmaps).
If for some reason you wish to keep using the old version, based on Ctypes, use PyRoaring 0.0.7.
Requirements
Environment like Linux and MacOS
Python 2.7, or Python 3.4 or better
A recent C compiler like GCC
The package manager pip
The Python package hypothesis (optional, for testing)
The Python package Cython (optional, for compiling pyroaring from the sources)
The Python package wheel (optional, to build a wheel for the library)
Installation
To install pyroaring on your local account, use the following command:
pip install pyroaring --user # installs PyRoaringBitMapFor a system-wide installation, use the following command:
pip install pyroaringNaturally, the latter may require superuser rights (consider prefixing the commands by sudo).
If you want to use Python 3 and your system defaults on Python 2.7, you may need to adjust the above commands, e.g., replace pip by pip3.
Manual compilation / installation
If you want to compile (and install) pyroaring by yourself, for instance to modify the Cython sources or because you do not have pip, follow these steps. Note that the Python package Cython is required.
Clone this repository.
git clone https://github.com/Ezibenroc/PyRoaringBitMap.git
cd PyRoaringBitMap
git submodule init && git submodule updateBuild pyroaring locally, e.g. to test a new feature you made.
python setup.py build_ext -i
python test.py # run the tests, optionnal but recommendedInstall pyroaring (use this if you do not have pip).
python setup.py install # may require superuser rights, add option --user if you wish to install it on your local accountPackage pyroaring.
python setup.py sdist
pip install dist/pyroaring-0.1.?.tar.gz # optionnal, to install the packageBuild a wheel.
python setup.py bdist_wheelFor all the above commands, two environment variables can be used to control the compilation.
DEBUG=1 to build pyroaring in debug mode.
ARCHI=<cpu-type> to build pyroaring for the given platform. The platform may be any keyword given to the -march option of gcc (see the documentation). Note that cross-compiling for a 32-bit architecture from a 64-bit architecture is not supported.
Example of use:
DEBUG=1 ARCHI=x86-64 python setup.py build_extUtilization
First, you can run the tests to make sure everything is ok:
pip install hypothesis --user
python test.pyYou can use a bitmap nearly as the classical Python set in your code:
from pyroaring import BitMap
bm1 = BitMap()
bm1.add(3)
bm1.add(18)
bm2 = BitMap([3, 27, 42])
print("bm1 = %s" % bm1)
print("bm2 = %s" % bm2)
print("bm1 & bm2 = %s" % (bm1&bm2))
print("bm1 | bm2 = %s" % (bm1|bm2))Output:
bm1 = BitMap([3, 18]) bm2 = BitMap([3, 27, 42]) bm1 & bm2 = BitMap([3]) bm1 | bm2 = BitMap([3, 18, 27, 42])
Benchmark
Pyroaring is compared with the built-in set and other implementations:
A Python wrapper of CRoaring called python-croaring
A Cython implementation of Roaring bitmaps called roaringbitmap
A Python implemenntation of ordered sets called sortedcontainers
The script quick_bench.py measures the time of different set operations. It uses randomly generated sets of size 1e6 and density 0.125. For each operation, the average time (in seconds) of 30 tests is reported.
The results have been obtained with:
CPU Intel i7-7820HQ
CPython version 3.5.3
gcc version 6.3.0
pyroaring commit 6c86765d0357492895fee99de8841ce42340f879
python-croaring commit 3aa61dde6b4a123665ca5632eb5b089ec0bc5bc4
roaringbitmap commit a32915f262eb4e39b854d942e005dc7381796808
sortedcontainers commit 53fd6c54aebe5b969adc87d4b5e6331be1e32079
operation |
pyroaring |
python-croaring |
roaringbitmap |
set |
sortedcontainers |
|---|---|---|---|---|---|
range constructor |
1.08e-04 |
1.14e-04 |
8.89e-05 |
4.18e-02 |
1.33e-01 |
ordered list constructor |
2.58e-02 |
5.25e-02 |
1.01e-01 |
1.23e-01 |
3.88e-01 |
list constructor |
9.18e-02 |
1.05e-01 |
1.26e-01 |
6.80e-02 |
3.47e-01 |
ordered array constructor |
4.07e-03 |
5.05e-03 |
2.19e-01 |
6.30e-02 |
2.13e-01 |
array constructor |
8.55e-02 |
9.11e-02 |
3.88e-01 |
1.05e-01 |
3.63e-01 |
element addition |
1.48e-07 |
5.23e-07 |
1.45e-07 |
1.06e-07 |
9.74e-07 |
element removal |
1.40e-07 |
5.41e-07 |
1.26e-07 |
1.02e-07 |
4.41e-07 |
membership test |
7.39e-08 |
6.59e-07 |
8.03e-08 |
5.90e-08 |
3.74e-07 |
union |
1.03e-04 |
1.37e-04 |
1.02e-04 |
1.03e-01 |
7.09e-01 |
intersection |
8.44e-04 |
8.05e-04 |
7.90e-04 |
3.73e-02 |
1.20e-01 |
difference |
1.02e-04 |
1.40e-04 |
9.97e-05 |
9.24e-02 |
3.16e-01 |
symmetric diference |
1.02e-04 |
1.36e-04 |
9.81e-05 |
1.34e-01 |
5.94e-01 |
equality test |
5.36e-05 |
5.62e-05 |
4.30e-05 |
1.56e-02 |
1.53e-02 |
subset test |
6.97e-05 |
6.00e-05 |
5.91e-05 |
1.54e-02 |
1.55e-02 |
conversion to list |
3.37e-02 |
2.12e-01 |
3.18e-02 |
3.50e-02 |
3.83e-02 |
pickle dump & load |
2.25e-04 |
3.56e-04 |
2.47e-04 |
1.46e-01 |
3.88e-01 |
“naive” conversion to array |
3.35e-02 |
2.25e-01 |
3.16e-02 |
6.39e-02 |
6.10e-02 |
“optimized” conversion to array |
1.20e-03 |
2.42e-02 |
nan |
nan |
nan |
selection |
7.69e-07 |
3.76e-05 |
1.13e-06 |
nan |
8.57e-06 |
slice |
3.23e-03 |
2.35e-01 |
1.23e-01 |
nan |
5.76e-01 |
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