Merge sherpa#696 (DougBurke) - Support python 3.8

Support python 3.8

.travis.yml

@@ -12,7 +12,7 @@ matrix:
     # We need to use TEST=none to remove the test-data submodule.
     # This used to be the Python 2.7 build (so used an old NumPy) but it has now
     # been bumped to "nearly latest" versions
-    - env: INSTALL_TYPE=develop TEST=none NUMPYVER="1.17" TRAVIS_PYTHON_VERSION="3.7"
+    - env: INSTALL_TYPE=develop TEST=none NUMPYVER="1.17" TRAVIS_PYTHON_VERSION="3.8"
     # Full build (including ds9 and xspec), Python 3.5, setup.py develop, astropy, matplotlib 2
     - env: XSPECVER="12.10.1b" NUMPYVER="1.11" FITS="astropy" INSTALL_TYPE=develop TEST=submodule MATPLOTLIBVER=2 TRAVIS_PYTHON_VERSION="3.5"
       sudo: required

README.md

@@ -70,6 +70,10 @@ documentation, and should be read if the following is not sufficient.
 It is strongly recommended that some form of *virtual environment* is
 used with Sherpa.
 
+Sherpa is tested against Python versions 3.5, 3.6, and 3.7. It is
+expected that it will work with Python 3.8 but testing has been
+limited.
+
 The last version of Sherpa which supported Python 2.7 is
 [Sherpa 4.11.1](https://doi.org/10.5281/zenodo.3358134).
 

docs/index.rst

@@ -30,6 +30,8 @@ Sherpa is released under the
 `GNU General Public License v3.0
 <https://github.com/sherpa/sherpa/blob/master/LICENSE>`_,
 and is compatible with Python versions 3.5, 3.6, and 3.7.
+It is expected that it will work with Python 3.8 but testing has been
+limited.
 Information on recent releases and citation information for
 Sherpa is available using the Digital Object Identifier (DOI) 
 `10.5281/zenodo.593753 <https://doi.org/10.5281/zenodo.593753>`_.

docs/install.rst

@@ -27,7 +27,8 @@ Requirements
 
 Sherpa has the following requirements:
 
-* Python 3.5, 3.6, or 3.7
+* Python 3.5, 3.6, or 3.7 (there has been limited testing with
+  Python 3.8)
 * NumPy (the exact lower limit has not been determined,
   but it is likely to be 1.7.0 or later)
 * Linux or OS-X (patches to add Windows support are welcome)

sherpa/astro/data.py

@@ -1,5 +1,5 @@
 #
-#  Copyright (C) 2008, 2015, 2016, 2017, 2018, 2019
+#  Copyright (C) 2008, 2015, 2016, 2017, 2018, 2019, 2020
 #            Smithsonian Astrophysical Observatory
 #
 #
@@ -2597,7 +2597,7 @@ def _world_to_physical(self, x0=None, x1=None):
     def get_logical(self):
         coord = self.coord
         x0, x1 = self.get_indep()
-        if coord is not 'logical':
+        if coord != 'logical':
             x0 = x0.copy()
             x1 = x1.copy()
             x0, x1 = getattr(self, '_' + coord + '_to_logical')(x0, x1)
@@ -2606,7 +2606,7 @@ def get_logical(self):
     def get_physical(self):
         coord = self.coord
         x0, x1 = self.get_indep()
-        if coord is not 'physical':
+        if coord != 'physical':
             x0 = x0.copy()
             x1 = x1.copy()
             x0, x1 = getattr(self, '_' + coord + '_to_physical')(x0, x1)
@@ -2615,7 +2615,7 @@ def get_physical(self):
     def get_world(self):
         coord = self.coord
         x0, x1 = self.get_indep()
-        if coord is not 'world':
+        if coord != 'world':
             x0 = x0.copy()
             x1 = x1.copy()
             x0, x1 = getattr(self, '_' + coord + '_to_world')(x0, x1)
@@ -2808,7 +2808,7 @@ def _init_data_space(self, filter, *data):
     def get_logical(self):
         coord = self.coord
         x0lo, x1lo, x0hi, x1hi = self.get_indep()
-        if coord is not 'logical':
+        if coord != 'logical':
             x0lo = x0lo.copy()
             x1lo = x1lo.copy()
             convert = getattr(self, '_' + coord + '_to_logical')
@@ -2823,7 +2823,7 @@ def get_logical(self):
     def get_physical(self):
         coord = self.coord
         x0lo, x1lo, x0hi, x1hi = self.get_indep()
-        if coord is not 'physical':
+        if coord != 'physical':
             x0lo = x0lo.copy()
             x1lo = x1lo.copy()
             convert = getattr(self, '_' + coord + '_to_physical')
@@ -2838,7 +2838,7 @@ def get_physical(self):
     def get_world(self):
         coord = self.coord
         x0lo, x1lo, x0hi, x1hi = self.get_indep()
-        if coord is not 'world':
+        if coord != 'world':
             x0lo = x0lo.copy()
             x1lo = x1lo.copy()
             convert = getattr(self, '_' + coord + '_to_world')

sherpa/instrument.py

@@ -1,6 +1,7 @@
 from __future__ import division
 #
-#  Copyright (C) 2008, 2016, 2018, 2019  Smithsonian Astrophysical Observatory
+#  Copyright (C) 2008, 2016, 2018, 2019, 2020
+#        Smithsonian Astrophysical Observatory
 #
 #
 #  This program is free software; you can redistribute it and/or modify
@@ -296,14 +297,20 @@ def init_kernel(self, kernel):
         # be centered on brightest pixel.
         brightPixel = list(numpy.where(kernel == kernel.max())).pop()
 
-        origin = None
         # if more than one pixel qualifies as brightest, such as const2D
         # use the middle of subkernel -- assumes the user provided center at
         # time of kernel extraction, so that should be middle of subkernel.
+        origin = None
         if (not numpy.isscalar(brightPixel)) and len(brightPixel) != 1:
             origin = set_origin(kshape)
         else:
-            origin = set_origin(kshape, brightPixel)
+            # brightPixel is a NumPy index (int64) which - as of NumPy 1.18
+            # and Python 3.8 - causes a TypeError with the message
+            # "only integer scalar arrays can be converted to a scalar index"
+            # to be thrown here if sent directly to set_origin. So
+            # we convert to a Python integer type.
+            #
+            origin = set_origin(kshape, int(brightPixel))
 
         if self.origin is None:
             self.origin = origin