Gravitus's profile - activity

OK, I guess that makes sense... thanks!

That makes sense slelievre, but I am still confused as to why I can use "v" by itself. Why can I do v*A if A was a 2x2 matrix without having to tell it that v is a row vector?

Almost, tmonteil. I would like to know how/if it can show it, in matrix form. For example, instead of declaring x and y as variables, we declare a 2x1 vector x, so it shows the hessian in terms of the _vector_ x...

Thanks tmonteil, however I am more confused now. If I try v*vC it works just find, but vC*v doesnt work - why the discrepancy? That is, why does it complain about the 'type' of data structure in one case, but does not complain about it in the other? Another thing: I tried to multiply v with a matrix A. It seems that it 'knows' how to interpret v regardless of which side I put it around A. Yet it does not know how to interpret v with A is substituted for vC? Not complaining, just trying to understand how it thinks. Thanks.

Hello,

So I have a 2x1 vector $\mathbf{x} \in R^2$, and a function on it called $f(\mathbf{x}) = log(\mathbf{1}^T \mathbf{x})$ which of course, returns a scalar.

I would like to compute the Hessian of this function in Sage, symbolically. That is, I would like it so show me what the 2x2 Hessian matrix would look like, but in terms of the elements of $x$, or even better, in terms of the vector $\mathbf{x}$.

Is there such a way? Thanks.

Hello all. Sage noob here. My friend recently told me about sage and convinced me to give it a whirl. (My background is MATLAB).

I made an account, and went to sage cell for a quick run. I typed this in:

v = vector([3, 4]);
vC = v.column();
vC*v

I would like to simply get the outer product of those two vectors. However it errors out.

I would like to think that I am boneheading something here, because this is a legitimate operation. I have multiple tutorial/documentation tabs open but nothing really elucidating why/how this doesnt work.

Would appreciate any insight.