Thank you Charles for the corrections. Cheers, N.Maniteja _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion On Thu, Jan 15, 2015 at 10:41 PM, Charles R Harris < charlesr.harris@gmail.com> wrote:
On Thu, Jan 15, 2015 at 9:44 AM, Maniteja Nandana < maniteja.modesty067@gmail.com> wrote:
Hello everyone,
I just wanted to highlight the point made by Charles, it would be great if he would clarify any mistakes in the points that I put forward.
Quoting the documentation,
In versions of NumPy prior to 1.7, this function always returned a new,independent array containing a copy of the values in the diagonal.
In NumPy 1.7 and 1.8, it continues to return a copy of the diagonal,but depending on this fact is deprecated. Writing to the resulting array continues to work as it used to, but a FutureWarning is issued.
In NumPy 1.9 it returns a read-only view on the original array. Attempting to write to the resulting array will produce an error.
In NumPy 1.10, it will return a read/write view, Writing to the returned array will alter your original array.
Though the expected behaviour has its pros and cons,the points put forward are :
1. revert the changes so that *PyArray_Diagonal *returns a *copy.* 2. introduce new API function *PyArray_Diagonal2, *which has a *copy *argument, so that copy or view can be returned. 3. if a *view* is to be returned, its *write-ability *depends on whether the *input* is writeable. 4. implement *PyArray_Diagonal *in terms of the new function, thought the default value of *copy *is unsure.
copy=True
1. Raise a *FutureWarning*, when trying to write to the result.
Old function should behave exactly as before, returning a writable copy.
1. add *copy *argument to the *diagonal *function and method, updating the function in *methods.c *and *fromnumeric.py, *probably in other places also. 2. Also update the release notes and documentation.
I would love to do the PR once a decision is reached.
Chuck
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