Add pure Python implementation

Author: gjbex

source-code/cython/Exceptions/.gitignore

@@ -0,0 +1,2 @@
+average.c
+average_pure.c

source-code/cython/Exceptions/Makefile

@@ -1,11 +1,16 @@
-VERSION = cpython-34m
+VERSION = cpython-311-x86_64-linux-gnu
 AVERAGE_LIB = average.$(VERSION).so
+AVERAGE_PURE_LIB = average_pure.$(VERSION).so
 
-all: $(AVERAGE_LIB)
+all: $(AVERAGE_LIB) $(AVERAGE_PURE_LIB)
 
 $(AVERAGE_LIB): average.pyx
 	python setup.py build_ext --inplace
 
+$(AVERAGE_PURE_LIB): average_pure.py
+	python setup.py build_ext --inplace
+
 clean:
 	python setup.py clean
-	rm -f average.c $(AVERAGE_LIB)
+	$(RM) average.c average_pure.c $(AVERAGE_LIB) $(AVERAGE_PURE_LIB)
+	$(RM) -r build

source-code/cython/Exceptions/README.md

@@ -2,9 +2,12 @@
 Error handling in Cython code.
 
 ## What is it?
-1. `average.pyx`: code to be compiled using Cython, implements two
+1. `average.pyx`: Cython code to be compiled using Cython, implements two
     functions to compute the average of an array slice, one with, the
     other without error handling.
+1. `average_pure.py`: pure Python code to be compiled using Cython,
+   implements two functions to compute the average of an array slice,
+   one with, the other without error handling.
 1. `setup.py`: Python build script.
 1. `Makefile`: make file to build the extension.
 1. `compute_average.py`: script to load the compiled module and call the

source-code/cython/Exceptions/average_pure.py

@@ -0,0 +1,29 @@
+import cython
+
+
+def average(data, m=0, n=None):
+    if n is None:
+        n = len(data)
+    return _average(memoryview(data), m, n)
+
+def average_no_except(data, m=0, n=None):
+    if n is None:
+        n = len(data)
+    return _average_no_except(memoryview(data), m, n)
+
+@cython.cfunc
+@cython.exceptval(-1.0, check=True)
+def _average(data, m: cython.int=0, n: cython.int=-1) -> cython.double:
+    i: cython.int
+    mean: cython.double = 0.0
+    for i in range(m, n):
+        mean += data[i]
+    return mean/(n - m + 1)
+
+@cython.cfunc
+def _average_no_except(data, m: cython.int=0, n: cython.int=-1) -> cython.double:
+    i: cython.int
+    mean: cython.double = 0.0
+    for i in range(m, n):
+        mean += data[i]
+    return mean/(n - m + 1)

source-code/cython/Exceptions/compute_average.py

@@ -2,24 +2,31 @@
 
 from argparse import ArgumentParser
 import array
-import average
 
-
-size = 10
+DEFAULT_SIZE = 10
 
 arg_parser = ArgumentParser(description='test Cython errors')
 arg_parser.add_argument('--m', type=int, default=0, help='lower bound')
-arg_parser.add_argument('--n', type=int, default=size, help='upper bound')
+arg_parser.add_argument('--n', type=int, default=DEFAULT_SIZE,
+                        help='upper bound')
+arg_parser.add_argument('--size', type=int, default=DEFAULT_SIZE,
+                        help='array size')
+arg_parser.add_argument('--implementation', choices=['pure', 'cython'],
+                        default='cython', help='implementation to use')
 options = arg_parser.parse_args()
-data = array.array('d', list(range(size)))
+if options.implementation == 'cython':
+    from average import average, average_no_except
+elif options.implementation == 'pure':
+    from average_pure import average, average_no_except
+data = array.array('d', list(range(options.size)))
 print('with except:')
 try:
-    print(average.average(data, options.m, options.n))
+    print(average(data, options.m, options.n))
 except Exception as e:
     print('caught exception {0}: {1}'.format(str(e.__class__), str(e)))
 print('without except:')
 try:
-    print(average.average_no_except(data, options.m, options.n))
+    print(average_no_except(data, options.m, options.n))
     print('no exception caught')
 except Exception as e:
     print('caught exception {0}: {1}'.format(e.__class__, str(e)))

source-code/cython/Exceptions/setup.py

@@ -4,5 +4,6 @@
 from Cython.Build import cythonize
 
 setup(
-    ext_modules=cythonize('average.pyx')
+    ext_modules=cythonize(['average.pyx', 'average_pure.py'],
+                          language_level='3str')
 )