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Questions tagged [weighted-least-squares]

This tag is for questions relating to weighted least squares, a generalization of ordinary least squares and linear regression in which the errors covariance matrix is allowed to be different from an identity matrix.

1 vote
1 answer
94 views

I have a question that is related to weighted least-squares and operator norm. Assume we have a model $y(x) = a_1 \psi_1 + \dots + a_n \psi_n(x)$ and its noisy $N (>n)$meaurements $$ \{ (x_1, y(x_1)...
박희인's user avatar
  • 141
0 votes
1 answer
288 views

I am trying to solve a standard least-squares problem of the form: $x = \text{argmin}|Ax-b|^2$, where $A$ has a non-trivial null space. I want the minimum 2-norm solution with the norm $\|x\|^2 = x^T ...
Amir Vaxman's user avatar
0 votes
0 answers
47 views

I'm trying to generate a decent $[3,1]$ rational least squares polynomial approximation to $\arcsin(x)+\sqrt{1-x^2}$ and failing dismally :( The problem is that for this particular combination of $N,D$...
Martin Brown's user avatar
4 votes
1 answer
124 views

The left pseudoinverse of $(A^TA)^{-1}A^T$ solves the problem of $\text{min} ||b-Ax||^2$. i.e. $x=(A^TA)^{-1}A^Tb$ is the solution to above problem. And there is a well-know property that if we add a ...
zvi's user avatar
  • 309
1 vote
2 answers
170 views

If I have a $(X, Y)$ dataset and want to model $y = f(x, \beta)$. In that case for OLS, I would have $$e(x_i, \beta) = f(x_i, \beta) - y_i$$ Then obviously I would have $$SSE = \sum_{i}e(x_i, \beta)^2$...
Ghosal_C's user avatar
  • 557
1 vote
0 answers
84 views

I've been tasked to calculate/forecast the weighted exposure of a financial product. I work with bunker prices and we have access to bunker future prices everyday. They look similar to this in an ...
zacchhh's user avatar
  • 11
2 votes
0 answers
95 views

I am considering a weighted least square problem with data $X \in \mathbb{R}^{n \times p}$, (diagonal) weight matrix $W \in \mathbb{R}^{n \times n}$ and responses $y \in \mathbb{R}^n$, i.e. finding $$\...
Fabi's user avatar
  • 21
0 votes
0 answers
175 views

I have a problem I fail to research properly, so I hope you may at least push me in the right direction (or maybe even provide me an answer right away?). I know how linear regression works, that it ...
AlpaY's user avatar
  • 111
0 votes
0 answers
44 views

I am currently working on a problem involving the minimization of the $\chi^2$ deviation between a model matrix ($C_{model}$) and a measured matrix ($C_{measured}$). by finding the best fit parameters ...
Accelerator's user avatar
2 votes
0 answers
178 views

Considering following linear model \begin{equation} y_t = X_t f_t + \varepsilon_t, \qquad t=1,\cdots, T \end{equation} where $y_t\in\Re^{300\times 1}$ and $X_t\in\Re^{300\times 60}$ are two given ...
Stephen Ge's user avatar
0 votes
0 answers
137 views

(also posted on CV, but I will try here too) I am trying to find out if what I am looking at is a known problem. I am considering the case of weighted least squares, and I am trying to find the ...
smallStackBigFlow's user avatar
1 vote
1 answer
228 views

I am trying to understand Jun Shao's proof of the asymptotic normality of weighted LSE in his book Mathematical Statistics. The theorem: Consider the model $X = Z\beta + \varepsilon$ with a full rank $...
mlcv2022's user avatar
  • 713
0 votes
1 answer
230 views

I was studying the weighted least squares algorithm and came across this formula for calculating the weighted result in terms of the original. Here $x_{LS}$ is the solution for $D=I$ I can't figure ...
Arthur's user avatar
  • 35
3 votes
0 answers
139 views

Let $x_1,...x_K \geq 0$ and $f$ be the piecewise-linear function given by $f(k)=x_k$ for every $1 \leq k \leq K$. Denote by $m$ the number of modes (i.e. local maxima) of $f$. Let's associate with ...
Skywear's user avatar
  • 383
2 votes
0 answers
114 views

We need to solve the following least square problem $$\min_x (Y-Ax)^TW(Y-Ax)$$ $$s.t. x^TA^TAx=1$$ $$c^Tx=0$$ in a closed form, where $Y \in \mathbb{R}^{n\times 1}$, $A \in \mathbb{R}^{n\times n}$, $W ...
user1034188's user avatar

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