bench_np_int_conversions.py

from timeit import timeit

N = int(1E6)

def bench_conversion(int_size):
  np_to_int = timeit('int(i)', setup='import numpy as np; i=np.int%d(4528)' % int_size, number=N)
  int_to_np = timeit('np.int%d(i)' % int_size, setup='import numpy as np; i=int(4528)', number=N)
  np_to_np = timeit('np.int%d(i)' % int_size, setup='import numpy as np; i=np.int%d(4528)' % int_size, number=N)
  print("np.int%d to int:\t%.3f ns/op" % (int_size, np_to_int*1E9/N))
  print("int to np.int%d:\t%.3f ns/op" % (int_size, np_to_int*1E9/N))
  print("np.int%d to np.int%d:\t%.3f ns/op" % (int_size, int_size, np_to_int*1E9/N))

pass_ = timeit('pass', setup='import numpy as np',number=N)
print("pass:\t%.3f ns/op" % (pass_*1E9/N))

int_to_int = timeit('int(i)', setup='import numpy as np; i = int(4528)', number=N)
print("int to int:\t%.3f ns/op" % (int_to_int*1E9/N))

for int_size in (8, 16, 32, 64):
  bench_conversion(int_size)


# Output on my Desktop
# System python, v2.7.16
# ----
# pass:   6.117 ns/op
# int to int:     71.524 ns/op
# np.int8 to int: 89.784 ns/op
# int to np.int8: 89.784 ns/op
# np.int8 to np.int8:     89.784 ns/op
# np.int16 to int:        86.715 ns/op
# int to np.int16:        86.715 ns/op
# np.int16 to np.int16:   86.715 ns/op
# np.int32 to int:        89.172 ns/op
# int to np.int32:        89.172 ns/op
# np.int32 to np.int32:   89.172 ns/op
# np.int64 to int:        88.072 ns/op
# int to np.int64:        88.072 ns/op
# np.int64 to np.int64:   88.072 ns/op