Numba is a Python package, usually you import numba
from Python and use the
Python application programming interface (API). However, Numba also ships with a
command line interface (CLI), i.e. a tool numba
that is installed when you
install Numba.
Currently, the only purpose of the CLI is to allow you to quickly show some information about your system and installation, or to quickly get some debugging information for a Python script using Numba.
To use the Numba CLI from the terminal, use numba
followed by the options
and arguments like --help
or -s
, as explained below.
Sometimes it can happen that you get a “command not found” error when you type
numba
, because your PATH
isn’t configured properly. In that case you can
use the equivalent command python -m numba
. If that still gives “command
not found”, try to import numba
as suggested here:
Dependency List.
The two versions numba
and python -m numba
are the same. The first is
shorter to type, but if you get a “command not found” error because your
PATH
doesn’t contain the location where numba
is installed, having the
python -m numba
variant is useful.
To use the Numba CLI from IPython or Jupyter, use !numba
, i.e. prefix the
command with an exclamation mark. This is a general IPython/Jupyter feature to
execute shell commands, it is not available in the regular python
terminal.
To see all available options, use numba --help
:
$ numba --help
usage: numba [-h] [--annotate] [--dump-llvm] [--dump-optimized]
[--dump-assembly] [--dump-cfg] [--dump-ast]
[--annotate-html ANNOTATE_HTML] [-s]
[filename]
positional arguments:
filename Python source filename
optional arguments:
-h, --help show this help message and exit
--annotate Annotate source
--dump-llvm Print generated llvm assembly
--dump-optimized Dump the optimized llvm assembly
--dump-assembly Dump the LLVM generated assembly
--dump-cfg [Deprecated] Dump the control flow graph
--dump-ast [Deprecated] Dump the AST
--annotate-html ANNOTATE_HTML
Output source annotation as html
-s, --sysinfo Output system information for bug reporting
The numba -s
(or the equivalent numba --sysinfo
) command prints a lot of
information about your system and your Numba installation and relevant
dependencies.
Remember: you can use !numba -s
with an exclamation mark to see this
information from IPython or Jupyter.
Example output:
$ numba -s
System info:
--------------------------------------------------------------------------------
__Time Stamp__
2019-05-07 14:15:39.733994
__Hardware Information__
Machine : x86_64
CPU Name : haswell
CPU count : 8
CPU Features :
aes avx avx2 bmi bmi2 cmov cx16 f16c fma fsgsbase invpcid lzcnt mmx movbe pclmul
popcnt rdrnd sahf sse sse2 sse3 sse4.1 sse4.2 ssse3 xsave xsaveopt
__OS Information__
Platform : Darwin-18.5.0-x86_64-i386-64bit
Release : 18.5.0
System Name : Darwin
Version : Darwin Kernel Version 18.5.0: Mon Mar 11 20:40:32 PDT 2019; root:xnu-4903.251.3~3/RELEASE_X86_64
OS specific info : 10.14.4 x86_64
__Python Information__
Python Compiler : Clang 4.0.1 (tags/RELEASE_401/final)
Python Implementation : CPython
Python Version : 3.7.3
Python Locale : en_US UTF-8
__LLVM information__
LLVM version : 7.0.0
__CUDA Information__
CUDA driver library cannot be found or no CUDA enabled devices are present.
Error class: <class 'numba.cuda.cudadrv.error.CudaSupportError'>
__ROC Information__
ROC available : False
Error initialising ROC due to : No ROC toolchains found.
No HSA Agents found, encountered exception when searching:
Error at driver init:
HSA is not currently supported on this platform (darwin).
:
__SVML Information__
SVML state, config.USING_SVML : False
SVML library found and loaded : False
llvmlite using SVML patched LLVM : True
SVML operational : False
__Threading Layer Information__
TBB Threading layer available : False
+--> Disabled due to : Unknown import problem.
OpenMP Threading layer available : False
+--> Disabled due to : Unknown import problem.
Workqueue Threading layer available : True
__Numba Environment Variable Information__
None set.
__Conda Information__
conda_build_version : 3.17.8
conda_env_version : 4.6.14
platform : osx-64
python_version : 3.7.3.final.0
root_writable : True
__Current Conda Env__
(output truncated due to length)
As shown in the help output above, the numba
command includes options that
can help you to debug Numba compiled code.
To try it out, create an example script called myscript.py
:
import numba
@numba.jit
def f(x):
return 2 * x
f(42)
and then execute one of the following commands:
$ numba myscript.py --annotate
$ numba myscript.py --annotate-html myscript.html
$ numba myscript.py --dump-llvm
$ numba myscript.py --dump-optimized
$ numba myscript.py --dump-assembly