Merge pull request #520 from carterbox/lib-warnings

DOC: Make it clearer which shared libraries are optional

source/tomopy/util/extern/__init__.py

@@ -49,12 +49,10 @@
 import ctypes
 import os
 import sys
-import logging
+import warnings
 
-logger = logging.getLogger(__name__)
 
-
-def c_shared_lib(lib_name, do_warn=True):
+def c_shared_lib(lib_name, error=True):
     """Get the path and import the C-shared library."""
     load_dll = ctypes.cdll.LoadLibrary
     ext = '.so'
@@ -67,17 +65,19 @@ def c_shared_lib(lib_name, do_warn=True):
     sharedlib = os.path.join(base_path, '%s%s' % (lib_name, ext))
     if os.path.exists(sharedlib):
         return load_dll(sharedlib)
-    # cannot find shared lib:
-    if do_warn is True:
-        logger.warning(
-            'OSError: ' +
-            'The following shared lib is missing!\n{}'.format(sharedlib))
+    if error:
+        raise ModuleNotFoundError(
+            f'The following shared library is missing:\n{sharedlib}')
+    warnings.warn(
+        'Some compiled functions are unavailable because an optional shared'
+        f' library is missing:\n{sharedlib}', ImportWarning)
 
 
-def MissingLibrary(function):
-    print(f"The {function} algorithm is unavailable."
-          " Check CMake logs to determine if TomoPy was"
-          " built with dependencies required by this algorithm.")
+def _missing_library(function):
+    raise ModuleNotFoundError(
+        f"The {function} algorithm is unavailable because its shared library"
+        " is missing. Check CMake logs to determine if TomoPy was"
+        " built with all dependencies required by this algorithm.")
 
 
 from tomopy.util.extern.recon import *

source/tomopy/util/extern/accel.py

@@ -52,21 +52,21 @@
 
 import tomopy.util.dtype as dtype
 from . import c_shared_lib
-from . import MissingLibrary
+from . import _missing_library
 
 __author__ = "Doga Gursoy"
 __copyright__ = "Copyright (c) 2015, UChicago Argonne, LLC."
 __docformat__ = 'restructuredtext en'
 __all__ = ['c_accel_mlem',
            'c_accel_sirt']
 
-LIB_TOMOPY_ACCEL = c_shared_lib("libtomopy-accel")
+LIB_TOMOPY_ACCEL = c_shared_lib("libtomopy-accel", error=False)
 
 
 def c_accel_mlem(tomo, center, recon, theta, **kwargs):
 
     if LIB_TOMOPY_ACCEL is None:
-        MissingLibrary("MLEM ACCEL")
+        _missing_library("MLEM ACCEL")
 
     if len(tomo.shape) == 2:
         # no y-axis (only one slice)
@@ -97,7 +97,7 @@ def c_accel_mlem(tomo, center, recon, theta, **kwargs):
 def c_accel_sirt(tomo, center, recon, theta, **kwargs):
 
     if LIB_TOMOPY_ACCEL is None:
-        return MissingLibrary("SIRT ACCEL")
+        _missing_library("SIRT ACCEL")
 
     if len(tomo.shape) == 2:
         # no y-axis (only one slice)

source/tomopy/util/extern/gridrec.py

@@ -51,21 +51,21 @@
 """
 import tomopy.util.dtype as dtype
 from . import c_shared_lib
-from . import MissingLibrary
+from . import _missing_library
 
 __author__ = "Doga Gursoy"
 __copyright__ = "Copyright (c) 2015, UChicago Argonne, LLC."
 __docformat__ = 'restructuredtext en'
 __all__ = ['c_gridrec']
 
 
-LIB_TOMOPY_GRIDREC = c_shared_lib("libtomopy-gridrec")
+LIB_TOMOPY_GRIDREC = c_shared_lib("libtomopy-gridrec", error=False)
 
 
 def c_gridrec(tomo, center, recon, theta, **kwargs):
 
     if LIB_TOMOPY_GRIDREC is None:
-        return MissingLibrary("gridrec")
+        _missing_library("gridrec")
 
     if len(tomo.shape) == 2:
         # no y-axis (only one slice)

test/test_tomopy/test_recon/test_rotation.py

@@ -94,6 +94,7 @@ def test_write_center(self):
                         str('{0:.2f}'.format(cen[m]) + '.tiff'))), True)
         shutil.rmtree(dpath)
 
+    @unittest.skipUnless(found_mkl, "Requires MKL")
     def test_find_center(self):
         sim = read_file('sinogram.npy')
         ang = np.linspace(0, np.pi, sim.shape[0])