from brian2 import diagonal)
diagonal(a, offset=0, axis1=0, axis2=1)¶
Return specified diagonals.
ais 2-D, returns the diagonal of
awith the given offset, i.e., the collection of elements of the form
a[i, i+offset]. If
ahas more than two dimensions, then the axes specified by
axis2are used to determine the 2-D sub-array whose diagonal is returned. The shape of the resulting array can be determined by removing
axis2and appending an index to the right equal to the size of the resulting diagonals.
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.
Starting 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 some future release, it will return a read/write view and writing to the returned array will alter your original array. The returned array will have the same type as the input array.
If you don’t write to the array returned by this function, then you can just ignore all of the above.
If you depend on the current behavior, then we suggest copying the returned array explicitly, i.e., use
np.diagonal(a).copy()instead of just
np.diagonal(a). This will work with both past and future versions of NumPy.