Just wanted to check in again - we've transitioned all the codegen of pycalphad from SymPy+Cython to symengine. Our test suite has gone from taking almost 30 minutes on my local dev machine to 3m 30s! 30s of that is just calling sympify, which we hope to remove in the future (I think pickle support is a blocker). The codegen and differentiation are about 10x faster and it looks like calling our objective is somewhere around 2x faster. The codegen boost is really impactful for our users and startup times will go from 1-5 minutes to just a few seconds. Thank you for this effort!
Nice. We would like to have serialization, but unfortunately none of us have experience in doing that in C++. symengine/symengine#1394
Any idea what some use cases of symengine would be where you need guarantees of compatibility as mentioned in the last comment?
Their 2 main downsides are that 1) they serialize into some custom format, which is not much usable as a data exchange format with other libraries/programs 2) they offer few guarantees of forward compatibility (e.g., if you serialize an object with Boost 1.66 it's not guaranteed to be deserializable with Boost 1.65).
and independent of platform
if you pickle in python 2 on osx, you can unpickle in python 3 on linux
you can't pickle in python3 on osx and unpickle in python 2 on linux
so, pickle is not forward compatible, but if 2 people used the same python minor version, they'll be compatible. If we use boost, there's an additional constraint on boost version
Though I very much understand that you don't want to implement serialization with a footgun that users might not notice
We are SymEngine and LLVM newbies though, if there are any new superpowers we may have gained, please let us know. ;)
python >3.4
Pickling and unpickling the LLVMDouble does not correctly reset the LLVMDoubleVisitor that is supposed to be in llvm_double[0].
Reproducing the bug
from symengine import symbols
x, y, z = symbols('x y z')
ex = x**2 + y**2 + z**2
from symengine import lambdify
l = lambdify([x, y, z], [ex], backend='llvm')
import pickle
print('pickle.loads(pickle.dumps(l)) == l :: ', pickle.loads(pickle.dumps(l)) == l)
print(l.__reduce__())
print(pickle.loads(pickle.dumps(l)).__reduce__())gives
pickle.loads(pickle.dumps(l)) == l :: False
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(<built-in function llvm_loading_func>, (3, 1, [()], True, 1, 'C', [0, 1], <class 'numpy.float64'>, b''))You can see that the pickled/unpickled version gives an empty byte string for the dumped LLVMDoubleVisitor bytes. @richardotis and I were tracking this down and the issue looks to be that the membuffer is not correctly reset in LLVMDoubleVisitor.loads here when called in self.llvm_double[0].loads as part of the LLVMDouble._load method here. In that case, the root fix would be to set the membuffer in LLVMDoubleVisitor.loads in the same way as LLVMDoubleVisitor.__init__.
A test for this might be to do pickle.loads(pickle.dumps(pickle.loads(pickle.dumps(l)))), which currently will kill the kernel with a LLVM ERROR: The file was not recognized as a valid object file
I'm not very fluent in C++
membuffer = s at the beginning of loads should fix it
Btw,
pickle.loads(pickle.dumps(l)) == l is always False because they don't have __eq__ implemented.
I'll open a PR first (symengine/symengine#1549) with an addition to the dump/save test to verify it fails and the test is working as intended, then I'll push the fix
I'm trying to get a symengine development environment set up and I'm having some trouble. SymEngine builds and the test binaries pass, but when I try to build symengine.py, I get
(calphadpy3) rotis@x86_64-conda_cos6-linux-gnu ~/git/symengine.py (master) $ python setup.py install build_ext --symengine-dir=$HOME/git/symengine/build --inplace
running install
running build
running build_ext
SymEngine_DIR : /home/rotis/git/symengine/build/lib/cmake/symengine
SymEngine Version : 0.4.0
-- Python include path: /home/rotis/anaconda3/envs/calphadpy3/include/python3.7m
-- Python version: 3.7
-- Python install path: /home/rotis/anaconda3/envs/calphadpy3/lib/python3.7/site-packages
-- Found CYTHON: cython
CMAKE_BUILD_TYPE : Release
CMAKE_CXX_FLAGS : -fvisibility-inlines-hidden -std=c++17 -fmessage-length=0 -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-strong -fno-plt -O2 -ffunction-sections -pipe
CMAKE_CXX_FLAGS_RELEASE : -Wall -Wextra -Wno-unused-parameter -fno-common -O3 -march=native -funroll-loops -std=c++11 -fPIC -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -DNDEBUG -fopenmp
CMAKE_CXX_FLAGS_DEBUG : -Wall -Wextra -Wno-unused-parameter -fno-common -g -ggdb -std=c++11 -fPIC -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -fopenmp
HAVE_SYMENGINE_MPFR : False
HAVE_SYMENGINE_MPC : False
HAVE_SYMENGINE_PIRANHA : False
HAVE_SYMENGINE_FLINT : False
HAVE_SYMENGINE_LLVM : True
Copying source of python wrappers into: /home/rotis/git/symengine.py
-- Configuring done
-- Generating done
-- Build files have been written to: /home/rotis/git/symengine.py
[ 25%] Building CXX object symengine/lib/CMakeFiles/symengine_wrapper.dir/symengine_wrapper.cpp.o
In file included from /home/rotis/git/symengine/build/lib/cmake/symengine/../../../include/symengine/mp_class.h:7:0,
from /home/rotis/git/symengine.py/symengine/lib/symengine_wrapper.cpp:620:
/home/rotis/git/symengine/build/lib/cmake/symengine/../../../include/symengine/mp_wrapper.h:5:10: fatal error: gmp.h: No such file or directory
#include <gmp.h>
^~~~~~~
compilation terminated.
gmake[2]: *** [symengine/lib/CMakeFiles/symengine_wrapper.dir/build.make:69: symengine/lib/CMakeFiles/symengine_wrapper.dir/symengine_wrapper.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:177: symengine/lib/CMakeFiles/symengine_wrapper.dir/all] Error 2
gmake: *** [Makefile:130: all] Error 2
error: error building project