# Tag Info

Accepted

### Why aren't Krylov subspace methods popular in the Machine Learning community compared to Gradient Descent?

On a basic level, I don't buy the argument that you have to "solve a linear system for many machine learning algorithms". Much more, you usually have to optimize a non-linear equation which ...
• 2,477

### Why aren't Krylov subspace methods popular in the Machine Learning community compared to Gradient Descent?

They aren't popular because they don't work. Nicol N. Schraudolph spent a few years on Krylov-like methods for Machine Learning. I first learned of his work at 2004 Machine Learning Summer School in ...
• 1,159
Accepted

### Notation for an optimization function that receives a vector of pairs

That seems correct, but I would suggest two minor improvements: Rearrange the pairs in a $(n+1)\times 2$ matrix  M = \begin{bmatrix} t_0 & v_0\\ \vdots & \vdots\\ t_n & v_n \end{bmatrix}...
• 8,730
Accepted

### Optimization software for real-valued functions of complex arguments

I sat down and worked a bit on this. Since I am only interested in the magnitude of the polynomial it might be helpful to employ the polar representation, i.e., $1 - z_j \lambda = r_j e^{i\phi_j}$. ...
• 601