Use symengine's new interface for lambda double

[isuruf]

Depends on symengine/symengine#1094

[isuruf]

Ready for review. LLVMDoubleVisitor should be another PR.

[certik]

That looks good, thanks!

[bjodah]

Looks great!

[isuruf]

Tests fail with
symengine.tests.test_lambdify.test_cse_list_input ... bin/test_travis.sh: line 19: 22264 Segmentation fault: 11 nosetests -v
I'll try to reproduce this locally

[bjodah]

Do you think #105 might be related?

[isuruf]

I just pushed a fix, let's see.

[sighingnow]

Hi @isuruf I'm afraid that simplify expressions before sending to sympy can't fix #105. In the implementation of sympy's cse function, line 530 of cse_main.py, we can see that all expressions must be instances of sympy's Basic class. However, we can't inherit symengine's Basic class from sympy's Basic class, as cdef classes can't inherit from normal Python classes, see cython doc. So, just simplify the expressions can't fix #105.

I think the correct way to fix it is casting expression to sympy's value before sending to the sympy.cse function. I mean, something like this:

    subs, new_exprs = cse([expr._sympy_() for expr in exprs])

[isuruf]

@sighingnow, sympy's sympify call Basic._sympy_(). So, it's the same thing

[sighingnow]

OK, I got it. Thanks very much for your reply @isuruf .

[isuruf]

Anybody have access to a Mac?

[isuruf]

On OS X, Python=3.5 Release mode fails while Debug mode passes

[bjodah]

I have ssh access to a Mac OS X machine, never used OX X though, I will try to debug.
EDIT: The Debug mode build on osx uses Python 2.7 as far as I can tell, no Python 3.5 build on OSX with Debug mode enabled?

[bjodah]

I'm struggling on OSX, I can't even get libsymengine ctest suite to pass, all tests fail like this:

Test project /Users/user/isuruf-llvm/symengine.py-llvm/symengine-cpp/build
      Start  1: test_rcp
 1/34 Test  #1: test_rcp .........................***Exception: Other  0.07 sec
...
The following tests FAILED:
      1 - test_rcp (OTHER_FAULT)
...

[isuruf]

Hmm, can you try the conda package for symengine?

[bjodah]

I will, but I'm afraid I've run out of time for today. I can try again next weekend. If you want to make progress earlier I could try to provide you with an account on that box with ssh access? Just email me your public ssh key or preferred password to my gmail: bjodah
and I'll try to set it up tomorrow.

[isuruf]

Thanks to @bjodah, I got access to a Mac and I was able to reproduce this.
Python 3.5 in Release mode with AppleClang triggers this segfault. Segfault is not there when a different Python version is used or in Debug mode or with gcc.
All the lambdify tests segfault and the segfault happens in init, before the __call__.
I'll update this thread, when I find something more.

[isuruf]

Added a fix. I'm not happy with the fix, but this is the best I could come up for now. I'll try to get a proper fix in later. Meanwhile, can somebody review the last commit , so that we can move on the LLVMDoubleVisitor?

[certik]

I think this is fine.

In the long run, I still think we should switch our Python wrappers to use the C API. Still use Cython, but just a C compiler and C API. This will speedup the compilation greatly, and get rid of all these bugs. We already have an issue for this at #91.

[certik]

+1 to merge as it is.