Improve symengine import time

[eendebakpt]

During the symengine import the pytest package is imported which adds to the import duration. The pytest package is only required for the unit testing. This PR moves the pytest import to a seperate file.

Output of importtime-waterfall symengine

symengine (2072)
  symengine.lib.symengine_wrapper (6247)
    symengine.lib (878)
    collections.abc (525)
    backports_abc (1292)
    numbers (537)
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                          email.errors (857)
                          email.encoders (292)
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                  importlib.metadata._meta (464)
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                  importlib.metadata._itertools (312)
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            _pytest._code.source (1124)
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            _pytest.pathlib (1087)
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        _pytest.assertion (1187)
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                _pytest.config.findpaths (671)
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              _pytest.fixtures (4043)
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            atomicwrites (882)
              tempfile (646)
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                ctypes._endian (605)
          _pytest.assertion.truncate (599)
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        _pytest.freeze_support (562)
        _pytest.legacypath (1176)
          _pytest.monkeypatch (861)
          _pytest.pytester (1799)
            gc (55)
            _pytest.tmpdir (1015)
          _pytest.terminal (1604)
        _pytest.logging (1252)
          logging (2000)
        _pytest.python_api (1145)
          decimal (433)
            _decimal (968)
        _pytest.recwarn (928)
    numpy (2141)
      numpy._globals (623)
      numpy.__config__ (345)
      numpy._distributor_init (278)
      numpy.core (814)
        numpy.version (281)
          numpy._version (249)
        numpy.core.multiarray (686)
          numpy.core.overrides (498)
            numpy.core._multiarray_umath (2904)
            numpy.compat._inspect (26)
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                numpy.core._ufunc_config (412)
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        numpy.core.memmap (364)
        numpy.core.function_base (354)
        numpy.core._machar (310)
        numpy.core.getlimits (421)
        numpy.core.einsumfunc (403)
        numpy.core._add_newdocs (1269)
          numpy.core._multiarray_tests (773)
        numpy.core._add_newdocs_scalars (558)
        numpy.core._dtype_ctypes (458)
        numpy.core._internal (875)
        numpy._pytesttester (308)
      numpy.lib (874)
        numpy.lib.mixins (532)
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          numpy.lib.type_check (347)
            numpy.lib.ufunclike (361)
        numpy.lib.index_tricks (502)
          numpy.matrixlib (350)
            numpy.matrixlib.defmatrix (509)
              numpy.linalg (356)
                numpy.linalg.linalg (682)
                  numpy.lib.twodim_base (435)
                    numpy.lib.stride_tricks (341)
                  numpy.linalg._umath_linalg (739)
          numpy.lib.function_base (760)
            numpy.lib.histograms (418)
        numpy.lib.nanfunctions (451)
        numpy.lib.shape_base (381)
        numpy.lib.polynomial (1045)
        numpy.lib.utils (792)
        numpy.lib.arraysetops (709)
        numpy.lib.npyio (2646)
          numpy.lib.format (659)
          numpy.lib._datasource (1053)
          numpy.lib._iotools (668)
        numpy.lib.arrayterator (385)
        numpy.lib.arraypad (374)
        numpy.lib._version (318)
      numpy.fft (435)
        numpy.fft._pocketfft (604)
          numpy.fft._pocketfft_internal (758)
        numpy.fft.helper (355)
      numpy.polynomial (427)
        numpy.polynomial.polynomial (635)
          numpy.polynomial.polyutils (459)
          numpy.polynomial._polybase (506)
        numpy.polynomial.chebyshev (528)
        numpy.polynomial.legendre (541)
        numpy.polynomial.hermite (431)
        numpy.polynomial.hermite_e (424)
        numpy.polynomial.laguerre (418)
      numpy.random (419)
        numpy.random._pickle (528)
          numpy.random.mtrand (1537)
            numpy.random.bit_generator (985)
              numpy.random._common (1074)
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                hmac (521)
                  _hashlib (1111)
                  hashlib (765)
                    _blake2 (75)
            numpy.random._bounded_integers (1014)
            numpy.random._mt19937 (781)
          numpy.random._philox (719)
          numpy.random._pcg64 (847)
          numpy.random._sfc64 (781)
          numpy.random._generator (924)
      numpy.ctypeslib (596)
      numpy.ma (449)
        numpy.ma.core (2536)
        numpy.ma.extras (1184)
  symengine.functions (1180)
  symengine.printing (638)

This PR: output of importtime-waterfall symengine

symengine (309)
  symengine.lib.symengine_wrapper (4226)
    symengine.lib (144)
    collections.abc (180)
    backports_abc (161)
    numbers (355)
    symengine.utilities (342)
      re (538)
        enum (614)
        sre_compile (280)
          _sre (66)
          sre_parse (333)
            sre_constants (252)
        copyreg (150)
      string (649)
        _string (36)
    numpy (1977)
      numpy._globals (310)
      numpy.__config__ (173)
      numpy._distributor_init (109)
      numpy.core (840)
        numpy.version (142)
          __future__ (137)
          numpy._version (113)
            json (368)
              json.decoder (465)
                json.scanner (380)
                  _json (156)
              json.encoder (410)
        numpy.core.multiarray (586)
          numpy.core.overrides (258)
            numpy.core._multiarray_umath (2305)
              datetime (719)
                math (58)
                _datetime (151)
            numpy.compat._inspect (29)
              numpy.compat (248)
                numpy.compat._inspect (176)
                numpy.compat._pep440 (2067)
                numpy.compat.py3k (207)
                  pathlib (620)
                    fnmatch (142)
                    ntpath (251)
                      nt (129)
                      nt (120)
                      nt (124)
                      nt (115)
                    errno (66)
                    urllib.parse (859)
                      urllib (127)
                  pickle5 (138)
                  pickle (701)
                    struct (286)
                      _struct (70)
                    _compat_pickle (222)
                    _pickle (107)
                    org.python.core (14)
                      org.python (25)
                        org (126)
        numpy.core.umath (186)
        numpy.core.numerictypes (348)
          numpy.core._string_helpers (140)
          numpy.core._type_aliases (344)
            numpy.core._dtype (153)
        numpy.core.numeric (841)
          numpy.core.shape_base (294)
            numpy.core.fromnumeric (839)
              numpy.core._methods (219)
                numpy.core._exceptions (333)
          numpy.core._ufunc_config (190)
          numpy.core.arrayprint (496)
          numpy.core._asarray (153)
        numpy.core.defchararray (763)
        numpy.core.records (276)
        numpy.core.memmap (181)
        numpy.core.function_base (209)
        numpy.core._machar (250)
        numpy.core.getlimits (249)
        numpy.core.einsumfunc (237)
        numpy.core._add_newdocs (1083)
          numpy.core._multiarray_tests (253)
        numpy.core._add_newdocs_scalars (2235)
          platform (1721)
          subprocess (471)
            signal (737)
            threading (465)
              _weakrefset (771)
            msvcrt (152)
            _posixsubprocess (52)
            select (66)
            selectors (441)
        numpy.core._dtype_ctypes (204)
        numpy.core._internal (958)
          ast (377)
            _ast (810)
          ctypes (845)
            _ctypes (377)
            ctypes._endian (247)
        numpy._pytesttester (151)
      numpy.lib (363)
        numpy.lib.mixins (245)
        numpy.lib.scimath (281)
          numpy.lib.type_check (319)
            numpy.lib.ufunclike (246)
        numpy.lib.index_tricks (375)
          numpy.matrixlib (120)
            numpy.matrixlib.defmatrix (264)
              numpy.linalg (145)
                numpy.linalg.linalg (662)
                  numpy.lib.twodim_base (429)
                    numpy.lib.stride_tricks (281)
                  numpy.linalg._umath_linalg (307)
          numpy.lib.function_base (904)
            numpy.lib.histograms (245)
        numpy.lib.nanfunctions (387)
        numpy.lib.shape_base (411)
        numpy.lib.polynomial (503)
        numpy.lib.utils (588)
          textwrap (1131)
        numpy.lib.arraysetops (269)
        numpy.lib.npyio (502)
          weakref (424)
          numpy.lib.format (201)
          numpy.lib._datasource (219)
          numpy.lib._iotools (299)
        numpy.lib.arrayterator (159)
        numpy.lib.arraypad (224)
        numpy.lib._version (161)
      numpy.fft (198)
        numpy.fft._pocketfft (490)
          numpy.fft._pocketfft_internal (124)
        numpy.fft.helper (164)
      numpy.polynomial (265)
        numpy.polynomial.polynomial (351)
          numpy.polynomial.polyutils (187)
          numpy.polynomial._polybase (934)
        numpy.polynomial.chebyshev (291)
        numpy.polynomial.legendre (249)
        numpy.polynomial.hermite (248)
        numpy.polynomial.hermite_e (372)
        numpy.polynomial.laguerre (250)
      numpy.random (203)
        numpy.random._pickle (260)
          numpy.random.mtrand (1068)
            numpy.random.bit_generator (461)
              numpy.random._common (537)
                backports_abc (160)
              secrets (170)
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                  binascii (79)
                hmac (325)
                  _hashlib (559)
                  hashlib (287)
                    _blake2 (61)
                    _sha3 (50)
                random (377)
                  bisect (144)
                    _bisect (34)
                  _sha512 (45)
                  _random (41)
            numpy.random._bounded_integers (213)
            numpy.random._mt19937 (167)
          numpy.random._philox (191)
          numpy.random._pcg64 (181)
          numpy.random._sfc64 (226)
          numpy.random._generator (501)
      numpy.ctypeslib (369)
      numpy.ma (256)
        numpy.ma.core (2471)
          inspect (1335)
            dis (398)
              opcode (250)
                _opcode (124)
            linecache (164)
              tokenize (860)
                token (156)
        numpy.ma.extras (913)
    atexit (42)
  symengine.functions (141)
  symengine.printing (136)

[bjodah]

This looks good. Out of curiosity: what was the import time before and after this change on your system?

[eendebakpt]

@bjodah Benchmark: time python -c "import time; t0=time.perf_counter(); import symengine; print(f'{1e3*(time.perf_counter()-t0):.2f} [ms]')" results in:

main: 126.40 [ms]
PR: 70.20 [ms]

(linux, python 3.8)

[bjodah]

Thanks!