numpy memory leak

a.py

from __future__ import print_function
import objgraph
import numpy as np

print('--------------------------------------------------')
print('Numpy info:')
print()
print(np.__version__)
print()
np.show_config()
print()
print('--------------------------------------------------')

def show_usage():
    import resource
    gb = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1024 / 1024
    print('max memory usage: {:.02f} GiB'.format(gb))

def show_growth():
    print('========= new instances =========')
    objgraph.show_growth()
    print('=================================')

print('BEFORE')
show_usage()
show_growth()
print()

a = np.array([])
b = np.array([])
for _ in range(10**7):
    np.dot(a, b)

print('AFTER')
show_usage()
show_growth()

python-2.out

$ python2 a.py            
--------------------------------------------------
Numpy info:

1.14.0.dev0+0032e53

lapack_opt_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    define_macros = [('HAVE_CBLAS', None)]
    language = c
blas_opt_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    define_macros = [('HAVE_CBLAS', None)]
    language = c
openblas_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    define_macros = [('HAVE_CBLAS', None)]
    language = c
blis_info:
  NOT AVAILABLE
openblas_lapack_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    define_macros = [('HAVE_CBLAS', None)]
    language = c
lapack_mkl_info:
  NOT AVAILABLE
blas_mkl_info:
  NOT AVAILABLE

--------------------------------------------------
BEFORE
max memory usage: 0.00 GiB
========= new instances =========
function                       3373     +3373
wrapper_descriptor             2241     +2241
dict                            937      +937
builtin_function_or_method      934      +934
tuple                           890      +890
method_descriptor               824      +824
weakref                         769      +769
getset_descriptor               576      +576
list                            462      +462
type                            311      +311
=================================

AFTER
max memory usage: 1.00 GiB
========= new instances =========
wrapper_descriptor     2250        +9
getset_descriptor       580        +4
member_descriptor       242        +3
weakref                 771        +2
dict                    939        +2
=================================

python-3.out

$ python3 a.py
--------------------------------------------------
Numpy info:

1.14.0.dev0+0032e53

blas_mkl_info:
  NOT AVAILABLE
blis_info:
  NOT AVAILABLE
openblas_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    language = c
    define_macros = [('HAVE_CBLAS', None)]
blas_opt_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    language = c
    define_macros = [('HAVE_CBLAS', None)]
lapack_mkl_info:
  NOT AVAILABLE
openblas_lapack_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    language = c
    define_macros = [('HAVE_CBLAS', None)]
lapack_opt_info:
    libraries = ['openblas', 'openblas']
    library_dirs = ['/usr/lib64']
    language = c
    define_macros = [('HAVE_CBLAS', None)]

--------------------------------------------------
BEFORE
max memory usage: 0.03 GiB
========= new instances =========
function                       4894     +4894
wrapper_descriptor             2033     +2033
dict                           1971     +1971
tuple                          1753     +1753
weakref                        1264     +1264
method_descriptor              1035     +1035
builtin_function_or_method      949      +949
getset_descriptor               827      +827
list                            579      +579
set                             538      +538
=================================

AFTER
max memory usage: 1.09 GiB
========= new instances =========
=================================

sysinfo.txt

$ uname -a
Linux arch-t430s 4.12.8-2-ARCH #1 SMP PREEMPT Fri Aug 18 14:08:02 UTC 2017 x86_64 GNU/Linux
$ python2 --version
Python 2.7.13
$ python3 --version
Python 3.6.2
$ ls -l /usr/lib64/libopenblas.so
lrwxrwxrwx 1 root root 35 Aug  9 12:50 /usr/lib64/libopenblas.so -> libopenblas_sandybridgep-r0.2.20.so