Changes for efficiency

[sapiris]

No description provided.

[mmaiers-nmdp]

Cython needs to be added to requirements.txt

Traceback (most recent call last):
  File "/private/tmp/py-graph-imputation/setup.py", line 30, in <module>
    from Cython.Build import cythonize
ModuleNotFoundError: No module named 'Cython'
make: *** [install] Error 1```

[mmaiers-nmdp]

even after pip install Cython the build fails with this error

[1/1] Cythonizing grim/imputation/imputegl/cutils.pyx

Error compiling Cython file:
------------------------------------------------------------
...
#cython: language_level=3
^
------------------------------------------------------------

grim/imputation/imputegl/cutils.pyx:1:0: 'grim/imputation/imputegl/cutils' is not a valid module name
Traceback (most recent call last):
  File "/private/tmp/py-graph-imputation/setup.py", line 85, in <module>
    ext_modules=cythonize([Extension("grim/imputation/imputegl/cutils", ["grim/imputation/imputegl/cutils.pyx"])])
  File "/private/tmp/py-graph-imputation/venv/lib/python3.9/site-packages/Cython/Build/Dependencies.py", line 1127, in cythonize
    cythonize_one(*args)
  File "/private/tmp/py-graph-imputation/venv/lib/python3.9/site-packages/Cython/Build/Dependencies.py", line 1250, in cythonize_one
    raise CompileError(None, pyx_file)
Cython.Compiler.Errors.CompileError: grim/imputation/imputegl/cutils.pyx
make: *** [install] Error 1

[mmaiers-nmdp]

There appear to be conflicts with:

 grim/imputation/imputegl/impute.py
grim/imputation/imputegl/networkx_graph.py
setup.py 

[pbashyal-nmdp]

Closing as the fixes for Cython and merge conflicts are fixed in #13