On Wed, Apr 16, 2008 at 11:01 AM, Gael Varoquaux < [EMAIL PROTECTED]> wrote:
> On Wed, Apr 16, 2008 at 10:06:05AM -0400, Alan G Isaac wrote: > > > if you want a submatrix you should provide both indices > > > (possibly including a ":"). > > > Yes. We exactly agree on this. > > Please persuade Stefan. > > Alan, instead of trying blindly to persuade Stefan, please listen to his > arguments. Or code an example implementation and show it to us. Stefan, > and incidently myself, believe your position cannot be described in a > consistent way, and that the day you try to code it, it will fall down. > This is why the RowVector and ColumnVector idea was proposed. For me it > is the only consistent proposal I have heard so far. I don't care that > much about all this, but I do care that you are trying to get developpers > lose their time on something that cannot work. > > > But none of this answers the question: > > what should you get when you iterate over a matrix. > > Stefan seems to agree with me to this extent: > > we should get its "rows". This disagreement is > > over what that means: > > are these submatrices, a new vector object, or 1d arrays? > > I claim that if you use matrices, you will find it > > natural for these to be 1d arrays. > > OK, let us pretend A[:, 1] returns a 1D array, as you seem to be wanting, > (A and B are matrices), > > What is A[1, :] * B then? You are multiply an array with a matrix. That > already is dodgy, but numpy deals with it, and you get what you want. > > What about B*A[:, 1]? You don't get what you want here. So you have > broken the user's expectation once again. > > The question is should we break this expectation (1), the expectation that > A[x][y] = A[x, y] (2), or add RowVector and ColumnVector (3)? > Dirac called them bra and ket vectors; put them together and you get bracket (inner product). Those might be alternative, shorter names. Chuck
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