[Numpy-discussion] boolean operations on boolean arrays
This is a very basic question. Suppose `a` and `b` are boolean arrays with the same shape. Are there any considerations besides convenience in choosing between: ab a*b logical_and(a,b) a|b a+b logical_or(a,b) ~aTrue-a logical_not(a) I somewhat expect the last column to be slowest as well as least convenient, since it is built to first convert non-booleans to booleans. Are there other differences? Also, is this made clear anywhere in the docs? Thanks, Alan Isaac ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] boolean operations on boolean arrays
On Sat, Apr 12, 2014 at 8:02 AM, Alan G Isaac alan.is...@gmail.com wrote: This is a very basic question. Suppose `a` and `b` are boolean arrays with the same shape. Are there any considerations besides convenience in choosing between: ab a*b logical_and(a,b) a|b a+b logical_or(a,b) ~aTrue-a logical_not(a) I somewhat expect the last column to be slowest as well as least convenient, since it is built to first convert non-booleans to booleans. Are there other differences? Also, is this made clear anywhere in the docs? The Python operators for ndarrays can be dynamically set, but they are initialized by the ufunc module (don't ask) as follows. #define BOOL_invert BOOL_logical_not #define BOOL_negative BOOL_logical_not #define BOOL_add BOOL_logical_or #define BOOL_bitwise_and BOOL_logical_and #define BOOL_bitwise_or BOOL_logical_or #define BOOL_bitwise_xor BOOL_logical_xor #define BOOL_multiply BOOL_logical_and #define BOOL_subtract BOOL_logical_xor So they are all equivalent to logical_* functions. Chuck ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] boolean operations on boolean arrays
On Sat, Apr 12, 2014 at 10:02 AM, Alan G Isaac alan.is...@gmail.com wrote: Are there any considerations besides convenience in choosing between: ab a*b logical_and(a,b) a|b a+b logical_or(a,b) ~aTrue-a logical_not(a) Boolean - is being deprecated: https://github.com/numpy/numpy/pull/4105 The choice between | and *+ is best dictated by what is more natural in your problem domain and how your functions should treat non-boolean types. ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
