Py_Initialize/Py_Finalize Not Working Twice with Numpy

Py_initialize / Py_Finalize not working twice with numpy

From the Py_Finalize docs:

Some extensions may not work properly if their initialization routine is called more than once; this can happen if an application calls Py_Initialize() and Py_Finalize() more than once.

Apparently Numpy is one of those. See also this message from Numpy-discussion.

Calling Py_Initialize() only once, and cleaning up at exit, is the way to go. (And it's should be faster, too!)

Python - C embedded Segmentation fault

I'm not quite sure how you don't seem to understand the solution posted in Py_initialize / Py_Finalize not working twice with numpy. The solution posted is quite simple: call Py_Initialize and Py_Finalize only once for each time your program executes. Do not call them every time you run the loop.

I assume that your program, when it starts, runs some initialization commands (which are only run once). Call Py_Initialize there. Never call it again. Also, I assume that when your program terminates, it has some code to tear down things, dump log files, etc. Call Py_Finalize there. Py_Initialize and Py_Finalize are not intended to help you manage memory in the Python interpreter. Do not use them for that, as they cause your program to crash. Instead, use Python's own functions to get rid of objects you don't want to keep.

If you really MUST create a new environment every time you run your code, you can use Py_NewInterpreter and to create a sub-interpreter and Py_EndInterpreter to destroy that sub-interpreter later. They're documented near the bottom of the Python C API page. This works similarly to having a new interpreter, except that modules are not re-initialized each time a sub-interpreter starts.

Unhandled exception at multiarray.pyd the 2nd time the program runs

I managed to work past this problem. It seems that some modules have problems when their initialization routines are called more than once, and numpyis one of those. The solution is to call Py_Finalize() only once at the very end of the program. Py_Initialize() can be called as many times as you want, as if Python is already initialized, Py_Initialize() is a non-op ...

And also, discovered that this solution turns the application faster since python doesn't need to restart every time there's a call to some of its function.

More information about it here

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