Impeller is a rotor used to increase (or decrease in case of turbines) the pressure and flow of a fluid.
It is also a thin Cython wrapper around modified fork of libxlsxwriter, partially compatible with Python XlsxWriter.
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Since the only reason to create this package is speed obsession, here are some crude results (work in progress and current problem is API compatibility). Results was received by running misc/simple_bench.py on Windows machine. Benchmark saving 10000 * 10 cells with extensive styling (every even row styled).
| Lib name | Timing in seconds | Times slower than Impeller |
|---|---|---|
| Impeller | Close time: 0.29 Total: 0.43 | 1x |
| Python XlsxWriter | Close time: 1.32 Total: 2.00 | 4.7x |
| xlwt | Close time: 0.34 Total: 1.30 | 3.0x |
| pyexcelerate | Close time: 1.88 Total: 2.17 | 5.0x |
| openpyxl | Close time: 2.21 Total: 7.56 | 17.6x |
Some comments: xlwt produces .xls files, not .xlsx and unable to handle more than 65536 cells (.xls format limitation and xlwt is not participating in second competition). openpyxl can actually not only write, but read and edit files (the only one who builds the elements tree, I suppose). openpyxl however was tested in write_only mode. XlsxWriter and Impeller are sharing the same API.
It is possible to run Impeller faster: instead of all-in-one write method you can use type-stricted methods like:
write_number_strict
write_string_strict
write_blank_strict
etc.
This methods are much faster, than simple write (so you can dump an array faster), but requires correct third parameter type. Also you can not use Excel notation to provide row and col ("A2", "E15" not working) in fast methods - you can convert this notation to indexes via xl_cell_to_rowcol function.
Another table for 100000 * 10 cells:
| Lib name | Timing in seconds | Times slower than Impeller |
|---|---|---|
| Impeller | Close time: 3.23 Total: 4.69 | 1x |
| Python XlsxWriter | Close time: 10.61 Total: 18.17 | 3.9x |
| pyexcelerate | Close time: 17.48 Total: 20.74 | 4.4x |
| openpyxl | Close time: 21.22 Total: 69.00 | 14.7x |
TODO: benchmark.c, comparing Cython, C and modified C versions
Unstable, not usable at all, work in progress.
TODO: Move to docs.
TODO: Other compilers
2.7, 3.5 Python supported.
How to build from source:
Since there are submodules, you will need to clone them too:
git clone --recursive https://github.com/m9psy/Impeller
- You will need to build zlib first. The build process is usual, CmakeLists for zlib was not changed. The only difference is different install path:
cd Impeller\zlib
mkdir msvc_solution64
cd msvc_solution64
cmake .. -G"Visual Studio 14 2015 Win64" -DCMAKE_INSTALL_PREFIX="..\..\libs\zlib" -DFAST_LMATCH=ON
cmake --build . --config Release --target INSTALL
Alternatively it is possible to find precompiled (or use modified one) zlib. By default zlib will be compiled with __cdecl convention. For __stdcall you can find ready-to-use solutions in contrib/vc folder.
- You will need to build libxlsxwirter and tell where zlib should be found.
cd Impeller\libxlsxwriter
mkdir msvc_solution64
cd msvc_solution64
cmake .. -G"Visual Studio 14 2015 Win64" -DBUILD_STATIC=OFF -DZLIB_ROOT=..\..\libs\zlib -DZLIB_INCLUDE_DIR=..\..\libs\zlib\include -DZLIB_LIBRARY=..\..\libs\zlib\lib\zlib.lib -DCMAKE_INSTALL_PREFIX=..\..\libs\XLSX
cmake --build . --config Release --target INSTALL
On Windows pointing to correct zlib location is somewhat tricky - you will see Performing Test ZLIB_COMPILES - Success message if everything is OK.
Both commands can be called via build_c_libs.cmd
- Cython is required for the next step. wheel is required - (
pip install -r dev_requirements.txt). You will need to build the extension:
cd Impeller
python setup.py build_ext bdist_wheel
As a result there will be .whl file in the dist directory - you can install it with pip install <wheel_name>.whl command.
- zlib is required. Use your favorite package manager like
sudo apt-get install zlib1g-dev. - build-essential is requried.
- checkinstall is required.
cd libxlsxwriter
make
sudo checkinstall make install
cd ..
python setup.py build_ext bdist_wheel
As a result there will be .whl file in the dist directory - you can install it with pip install <wheel_name>.whl command.