Fisher — 22 discussions

  1. shahbaznihal

    Graduate Computing the Fisher Matrix numerically

    Hi, I have been studying the Fisher matrix to apply in a project. I understand how to compute a fisher matrix when you have a simple model for example which is linear in the model parameters (in that case the derivatives of the model with respect to the parameters are independent of the...
  2. F

    Undergrad How to Get Final Fisher Matrix from 2 Matrices

    I have 2 Fisher matrixes which represent information for the same variables (I mean columns/rows are the same in the 2 matrixes). Now I would like to make the cross synthesis of these 2 matrixes by applying for each parameter the well known formula (coming from Maximum Likelihood Estimator...
  3. J

    Graduate Why is the quantum Fisher information useful in quantum metrology?

    I'm getting interested in quantum-enhanced metrology and have come across the quantum Fisher information (QFI) as a measure of how much a quantum state ##|\Psi(\theta)\rangle## changes with respect to some variable, for example, the phase accumulated during an interferometer, ##\theta##. This is...
  4. F

    Graduate Fisher matrix information gain from merging galaxy bias data

    In the context of a forecast, I am currently working on Fisher's formalism which is part of a more general theory, that of information. My problem applies to estimating cosmological parameters from input data with the Fisher formalism and recipes to build a Fisher matrix. The context is...
  5. F

    Undergrad Cross-correlations: what size to select for the matrix?

    Hello, I am working on Fisher's formalism in order to get constraints on cosmological parameters. I am trying to do cross-correlation between 2 types of galaxy populations (LRG/ELG) into a total set of 3 types of population (BGS,LRG,ELG). From the following article...
  6. F

    Undergrad Fisher matrix - equivalence or not between sequences

    I am currently studying Fisher's formalism as part of parameter estimation. From this documentation : They that Fisher matrix is the inverse matrix of the covariance matrix. Initially, one builds a matrix "full" that takes into account all the parameters. 1) Projection : We can then do...
  7. T

    Showing Rejection Region Equality with Fisher Distribution

    Homework Statement [/B] For reference: Book: Mathematical Statistics with Applications, 7th Ed., by Wackerly, Mendenhall, and Scheaffer. Problem: 10.81 From two normal populations with respective variances ##\sigma_1^2## and ##\sigma_2^2##, we observe independent sample variances ##S_1^2## and...
  8. diegzumillo

    Graduate Zeros of the partition function (Yang-Lee and Fisher zeros)

    Hey there, Just wondering where I can get a nice treatment of this with derivations. I could swear I read about this in Jon Cardy's Scaling and renormalization in statistical physics but I can't find it again so maybe I was wrong.
  9. X

    Undergrad What is the C_l in the Fisher Matrix For An CMB Survey?

    I'm trying to construct a Fisher Forecast for the upcoming S4 CMB survey. I don't understand what the C_l is in this formula. It is H(z) and the Angular Distance? Or is it some covariance matrix and if it is a covariance matrix how do I calculate it considering the experiment hasn't been done...
  10. X

    Graduate Fisher matrix elements too large for EUCLID survey constraints

    I'm trying to recreate the results of this paper https://arxiv.org/pdf/1607.08016.pdf to obtain the constraints for the matter density and Hubble constant h. However every time I try to create there results my Fisher Matrix has elements of order of 10^14 which is far to high. I suspect this is...
  11. X

    Graduate How To Do Fisher Forecasting For Constraining Parameters

    I'm doing a Fisher Forecast to satisfy my experimental physics requirement. I never done anything like this before so I'm kind of in the dark of how to proceed. I have done some readings on Fisher Forecasting and would like to outline how I would do it and then ask if you can tell me if I'm...
  12. Greg Bernhardt

    News Carrie Fisher dies at 60

    Carrie Fisher, Child of Hollywood and ‘Star Wars’ Royalty, Dies at 60 http://www.nytimes.com/2016/12/27/movies/carrie-fisher-dead-star-wars-princess-leia.html?_r=0
  13. RooksAndBooks

    Carrie Fisher, Actress of Princess Leia, Dies at 60

    More at http://www.rollingstone.com/movies/news/carrie-fisher-princess-leia-in-star-wars-dead-at-60-w457713 You will be missed, Carrie Fisher.
  14. D

    Graduate Maximum Likelihood and Fisher Information

    Homework Statement Let X1, X2,...Xn be a random sample from pdf, f(x|θ) = θx-2 where 0 < θ ≤ x < ∞ Find the MLE of θMy attempt: Likelihood fxn: L(θ|x) = ∏θx-2 = θn∏ θx-2 And to find MLE, I take Log of that function and partial derivative (w.r.t θ, of log L(θ|x) and set that = 0, and get...
  15. J

    Mathematica Computing Fisher information of exponential sum pdf in Mathematica

    Hello, I'm trying to calculate Fisher information (and eventually the Cramer-Rao lower bound) for this particular pdf with Mathematica: \text{pte}[t,\Theta ] = \frac{P_{\text{ec}}}{\tau _d-\tau _r}\left[e^{\frac{-(t-\Theta )}{\tau _d}}-e^{\frac{-(t-\Theta )}{\tau _r}}\right]...
  16. W

    Graduate Fisher Information Matrix: Equivalent Expressions

    I don't understand the following step regarding the (i,j)^{th} element of the Fisher Information Matrix, \textbf{J}: J_{ij}\triangleq\mathcal{E}\left\{ \frac{\partial}{\partial\theta_{i}}L_{\textbf{x}}(\textbf{θ})\frac{\partial}{\partial\theta_{j}} L_{\mathbf{x}}(\textbf{θ})\right\} \\...
  17. A

    [Quantum Mechanics] Quantum Fisher Information for a Pure State

    Hi everyone. Homework Statement We are given N spins 1/2. A rotation is defined as \rho_\theta=e^{-i\theta J_n}\rho_\theta e^{i\theta J_n} on an Hilbert Space H, with J_n=n_xJ_x+n_yJ_y+n_zJ_z\:,\quad n_x^2+n_y^2+n_z^2=1, and \theta isn't related to any observable. Given a quantum state...
  18. S

    Graduate How to understand fisher information ?

    How to understand "fisher information"? Hello, I am trying to understand what "fisher information is." It is defined as V [∂/∂∅(lnf(X,∅)) ]=E[ (∂/∂∅[lnf(X,∅)])^2 ]. From Wikipedia: Can you please help me understand why this is the case? How can this be explained by looking at the...
  19. L

    Graduate Invariance of the Fisher matrix

    Fisher matrix=(minus the) average of the second derivative of the log-likelihood with respect to the parameters It seems to me the Fisher matrix for Gaussian data is invariant with respect to any (non-singular) linear transformation of the data; if correct this is a very useful property...
  20. H

    Graduate Fisher matrix for multivariate normal distribution

    The fisher information matrix for multivariate normal distribution is said at many places to be simplified as: \mathcal{I}_{m,n} = \frac{\partial \mu^\mathrm{T}}{\partial \theta_m} \Sigma^{-1} \frac{\partial \mu}{\partial \theta_n}.\ even on...
  21. S

    Graduate What is Fisher information and how does it relate to information geometry?

    Maybe it is a good idea to have mathematical tutorials like in the subforum about Physics. I have no homework anymore :smile: but tend to think that doing mathematics is a skill that always pays back at the end. First thing I want to know what https://en.wikipedia.org/wiki/Fisher_information...
  22. L

    Have You Considered the Role of Fisher Information in Physics?

    Have some of you read this book by Roy Friedel? What are your comment? I am also interrested in other sources about "information" and "Fisher information" as it could be used in physics. Thanks Michel