Charles Greathouse on Tue, 02 Apr 2013 15:05:22 +0200 |
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Re: slice of matrices |
Dear PARI developers,
We are contemplating a minor change in the semantic of matrix slices.
Currently all matrix slices are t_MAT.
? M=[1,2,3;4,5,6]
%1 = [1,2,3;4,5,6]
? M[1,1..2]
%2 = Mat([1,2])
? M[1..2,1]
%3 = [1;4]
However in this two last cases, the user might legitimely expect that
the following holds:
M[1,1..2] = M[1,][1..2]
M[1..2,1] = M[,1][1..2]
Thus it should be:
? M[1,1..2]
%3 = [1,2]
? M[1..2,1]
%2 = [1,4]~
(i.e t_VEC/t_COL and not t_MAT).
Of course
M[1..1,1..2] and M[1..2,1..1] would still return a t_MAT.
Opinions ?
Cheers,
Bill.