BLD: add language_level=3 to .pyx files.

Silences useless build warnings, and should generate more appropriate
code.

scipy/_lib/_ccallback_c.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 #
 # Test function exports
 #

scipy/_lib/_ccallback_c.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 from cpython.pycapsule cimport (

scipy/_lib/messagestream.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 cimport cython
 from libc cimport stdio, stdlib
 

scipy/_lib/messagestream.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 cimport cython
 from libc cimport stdio, stdlib
 from cpython cimport PyBytes_FromStringAndSize, PY_VERSION_HEX

scipy/cluster/_hierarchy.pyx

@@ -1,4 +1,4 @@
-# cython: boundscheck=False, wraparound=False, cdivision=True
+# cython: language_level=3, boundscheck=False, wraparound=False, cdivision=True
 from __future__ import absolute_import
 
 import numpy as np

scipy/cluster/_optimal_leaf_ordering.pyx

@@ -1,3 +1,4 @@
+# cython: language_level=3
 # cython: profile=False
 # cython: linetrace=False
 # distutils: define_macros=CYTHON_TRACE_NOGIL=1
@@ -88,7 +89,7 @@ cdef int _simultaneous_sort(float* dist, int* idx,
         # The smallest of the three is moved to the beginning of the array,
         # the middle (the pivot value) is moved to the end, and the largest
         # is moved to the pivot index.
-        pivot_idx = size / 2
+        pivot_idx = size // 2
         if dist[0] > dist[size - 1]:
             dual_swap(dist, idx, 0, size - 1)
         if dist[size - 1] > dist[pivot_idx]:

scipy/cluster/_vq.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Cython rewrite of the vector quantization module, originally written
 in C at src/vq.c and the wrapper at src/vq_module.c. This should be

scipy/interpolate/_bspl.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Routines for evaluating and manipulating B-splines.
 

scipy/interpolate/_ppoly.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Routines for evaluating and manipulating piecewise polynomials in
 local power basis.

scipy/interpolate/interpnd.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Simple N-D interpolation
 

scipy/io/matlab/mio5_utils.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 ''' Cython mio5 utility routines (-*- python -*- like)
 
 '''

scipy/io/matlab/mio_utils.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 cimport numpy as np
 
 cpdef object squeeze_element(np.ndarray)

scipy/io/matlab/mio_utils.pyx

@@ -1,4 +1,7 @@
 # -*- python -*- like file
+
+# cython: language_level=3
+
 ''' Utilities for generic processing of return arrays from read
 '''
 

scipy/io/matlab/streams.pxd

@@ -1,5 +1,7 @@
 # -*- python -*- or rather like
 
+# cython: language_level=3
+
 cdef class GenericStream:
     cdef object fobj
 

scipy/linalg/_decomp_update.pyx.in

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Routines for updating QR decompositions
 

scipy/linalg/_generate_pyx.py

@@ -110,7 +110,8 @@ def pyx_decl_sub(name, args, header_name):
                                    argnames=argnames, header_name=header_name)
 
 
-blas_pyx_preamble = '''# cython: boundscheck = False
+blas_pyx_preamble = '''# cython: language_level=3
+# cython: boundscheck = False
 # cython: wraparound = False
 # cython: cdivision = True
 
@@ -158,7 +159,10 @@ def make_blas_pyx_preamble(all_sigs):
     return blas_pyx_preamble.format("\n- ".join(names))
 
 
-lapack_pyx_preamble = '''"""
+lapack_pyx_preamble = '''# cython: language_level=3
+
+"""
+
 LAPACK functions for Cython
 ===========================
 
@@ -470,7 +474,9 @@ def pxd_decl(name, ret_type, args):
     return pxd_template.format(name=name, ret_type=ret_type, args=args)
 
 
-blas_pxd_preamble = """# Within scipy, these wrappers can be used via relative or absolute cimport.
+blas_pxd_preamble = """# cython: language_level=3
+
+# Within scipy, these wrappers can be used via relative or absolute cimport.
 # Examples:
 # from ..linalg cimport cython_blas
 # from scipy.linalg cimport cython_blas
@@ -494,7 +500,9 @@ def generate_blas_pxd(all_sigs):
     return blas_pxd_preamble + body
 
 
-lapack_pxd_preamble = """# Within scipy, these wrappers can be used via relative or absolute cimport.
+lapack_pxd_preamble = """# cython: language_level=3
+
+# Within scipy, these wrappers can be used via relative or absolute cimport.
 # Examples:
 # from ..linalg cimport cython_lapack
 # from scipy.linalg cimport cython_lapack

scipy/linalg/_solve_toeplitz.pyx

@@ -1,6 +1,6 @@
 # Author: Robert T. McGibbon, December 2014
 #
-# cython: boundscheck=False, wraparound=False, cdivision=True
+# cython: language_level=3, boundscheck=False, wraparound=False, cdivision=True
 from __future__ import absolute_import
 
 from numpy import zeros, asarray, complex128, float64

scipy/ndimage/src/_cytest.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from numpy cimport npy_intp as intp
 
 cdef int _filter1d(double *input_line, intp input_length, double *output_line,

scipy/ndimage/src/_cytest.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 from cpython.mem cimport PyMem_Malloc, PyMem_Free

scipy/ndimage/src/_ni_label.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 ######################################################################
 # Cython version of scipy.ndimage.measurements.label().
 # Requires Cython version 0.17 or greater due to type templating.

scipy/optimize/_group_columns.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Cython implementation of columns grouping for finite difference Jacobian
 estimation. Used by ._numdiff.group_columns.

scipy/optimize/_lsq/givens_elimination.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 cimport cython

scipy/optimize/_trlib/_trlib.pyx

@@ -1,6 +1,8 @@
+# cython: language_level=3
+
 from scipy.optimize._trustregion import (_minimize_trust_region, BaseQuadraticSubproblem)
 import numpy as np
-cimport ctrlib
+from . cimport ctrlib
 cimport libc.stdio
 cimport numpy as np
 

scipy/optimize/_trlib/ctrlib.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # MIT License
 #
 # Copyright (c) 2016--2017 Felix Lenders

scipy/signal/_max_len_seq_inner.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Author: Eric Larson
 # 2014
 

scipy/signal/_peak_finding_utils.pyx

@@ -1,6 +1,7 @@
-#cython: wraparound=False
-#cython: boundscheck=False
-#cython: nonecheck=False
+# cython: language_level=3
+# cython: wraparound=False
+# cython: boundscheck=False
+# cython: nonecheck=False
 
 """Utility functions for finding peaks in signals."""
 

scipy/signal/_spectral.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Author: Pim Schellart
 # 2010 - 2011
 

scipy/signal/_upfirdn_apply.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # -*- coding: utf-8 -*-
 
 # Code adapted from "upfirdn" python library with permission:

scipy/sparse/_csparsetools.pyx.in

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # -*- cython -*-
 #
 # Tempita-templated Cython file

scipy/sparse/csgraph/_min_spanning_tree.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Author: Jake Vanderplas  -- <vanderplas@astro.washington.edu>
 # License: BSD, (C) 2011
 

scipy/sparse/csgraph/_reordering.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Author: Paul Nation  -- <nonhermitian@gmail.com>
 # Original Source: QuTiP: Quantum Toolbox in Python (qutip.org)
 # License: New BSD, (C) 2014

scipy/sparse/csgraph/_shortest_path.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Routines for performing shortest-path graph searches
 

scipy/sparse/csgraph/_tools.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Tools and utilities for working with compressed sparse graphs
 """

scipy/sparse/csgraph/_traversal.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Routines for traversing graphs in compressed sparse format
 """

scipy/spatial/_hausdorff.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Directed Hausdorff Code
 

scipy/spatial/_voronoi.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Spherical Voronoi Cython Code
 

scipy/spatial/ckdtree.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Copyright Anne M. Archibald 2008
 # Additional contributions by Patrick Varilly and Sturla Molden 2012
 # Revision by Sturla Molden 2015

scipy/spatial/qhull.pxd

@@ -1,4 +1,7 @@
 # -*-cython-*-
+
+# cython: language_level=3
+
 """
 Qhull shared definitions, for use by other Cython modules
 

scipy/spatial/qhull.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 """
 Wrappers for Qhull triangulation, plus some additional N-D geometry utilities
 

scipy/special/_comb.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 cdef extern from "limits.h":

scipy/special/_ellip_harm.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 # Copyright (c) 2012, Jaydeep P. Bardhan
 # Copyright (c) 2012, Matthew G. Knepley
 # Copyright (c) 2014, Janani Padmanabhan
@@ -63,7 +65,7 @@ cdef inline double* lame_coefficients(double h2, double k2, int n, int p,
 
     cdef double s2, alpha, beta, gamma, lamba_romain, pp, psi, t1, tol, vl, vu
     cdef int r, tp, j, size, i, info, lwork, liwork, c, iu
-    cdef char t
+    cdef Py_UNICODE t
 
     r = n/2
     alpha = h2

scipy/special/_ellip_harm_2.pxd

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 cdef double _F_integrand(double t, void *data) nogil
 cdef double _F_integrand1(double t, void *data) nogil
 cdef double _F_integrand2(double t, void *data) nogil

scipy/special/_ellip_harm_2.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 import ctypes

scipy/special/_generate_pyx.py

@@ -77,6 +77,9 @@
 UFUNCS_EXTRA_CODE_COMMON = """\
 # This file is automatically generated by _generate_pyx.py.
 # Do not edit manually!
+
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 include "_ufuncs_extra_code_common.pxi"
@@ -94,11 +97,15 @@
 """
 
 CYTHON_SPECIAL_PXD = """\
+# cython: language_level=3
+#
 # This file is automatically generated by _generate_pyx.py.
 # Do not edit manually!
 """
 
 CYTHON_SPECIAL_PYX = """\
+# cython: language_level=3
+#
 # This file is automatically generated by _generate_pyx.py.
 # Do not edit manually!
 \"\"\"
@@ -1180,6 +1187,8 @@ def generate_ufuncs(fn_prefix, cxx_fn_prefix, ufuncs):
     # for _ufuncs_cxx*
     cxx_defs = []
     cxx_pxd_defs = [
+        "# cython: language_level=3",
+        "",
         "from . cimport sf_error",
         "cdef void _set_action(sf_error.sf_error_t, sf_error.sf_action_t) nogil"
     ]

scipy/special/_test_round.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 import numpy as np

scipy/stats/_stats.pyx

@@ -1,3 +1,5 @@
+# cython: language_level=3
+
 from __future__ import absolute_import
 
 from cpython cimport bool