I am attempting to create a function which increments a Gray code count, while returning which bit was flipped. I am implementing this in C with a Cython wrapper to be able to access it in Sage.
On the Sage command line, I am trying to load this Cython file:
cdef extern from "gray_2.c":
long next_gray_code(long* x, long* parity)
With this C file:
long next_gray_code(long* x, long* parity) {
y = -(*x)&(*x);
*x = (*x)^(y << 1);
return log2(y) + 1; }
And I am getting this error:
Compiling ./gray.spyx...
---------------------------------------------------------------------------
UnicodeDecodeError Traceback (most recent call last)
/usr/lib/python2.7/dist-packages/IPython/core/interactiveshell.pyc in run_code(self, code_obj, result)
2896 if result is not None:
2897 result.error_in_exec = sys.exc_info()[1]
-> 2898 self.showtraceback()
2899 else:
2900 outflag = 0
/usr/lib/python2.7/dist-packages/IPython/core/interactiveshell.pyc in showtraceback(self, exc_tuple, filename, tb_offset, exception_only)
1822 except Exception:
1823 stb = self.InteractiveTB.structured_traceback(etype,
-> 1824 value, tb, tb_offset=tb_offset)
1825
1826 self._showtraceback(etype, value, stb)
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in structured_traceback(self, etype, value, tb, tb_offset, number_of_lines_of_context)
1404 self.tb = tb
1405 return FormattedTB.structured_traceback(
-> 1406 self, etype, value, tb, tb_offset, number_of_lines_of_context)
1407
1408
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in structured_traceback(self, etype, value, tb, tb_offset, number_of_lines_of_context)
1312 # Verbose modes need a full traceback
1313 return VerboseTB.structured_traceback(
-> 1314 self, etype, value, tb, tb_offset, number_of_lines_of_context
1315 )
1316 else:
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in structured_traceback(self, etype, evalue, etb, tb_offset, number_of_lines_of_context)
1162
1163 formatted_exception = self.format_exception_as_a_whole(etype, evalue, etb, number_of_lines_of_context,
-> 1164 tb_offset)
1165
1166 colors = self.Colors # just a shorthand + quicker name lookup
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in format_exception_as_a_whole(self, etype, evalue, etb, number_of_lines_of_context, tb_offset)
1111 return ""
1112
-> 1113 last_unique, recursion_repeat = find_recursion(orig_etype, evalue, records)
1114
1115 frames = self.format_records(records, last_unique, recursion_repeat)
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in find_recursion(etype, value, records)
453 # quarter of the traceback (250 frames by default) is repeats, and find the
454 # first frame (from in to out) that looks different.
--> 455 if not is_recursion_error(etype, value, records):
456 return len(records), 0
457
/usr/lib/python2.7/dist-packages/IPython/core/ultratb.pyc in is_recursion_error(etype, value, records)
439 # a recursion error.
440 return (etype is recursion_error_type) \
--> 441 and "recursion" in str(value).lower() \
442 and len(records) > 500
443
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe2 in position 1542: ordinal not in range(128)
Which makes no sense to me since nothing I am doing has anything to do with strings, nor am I using anything but ascii characters in my code files (also, the trace is unhelpful since none of the referenced functions are in my code). What is going on here and how do I fix it?
