Machine Learning: Generative and Discriminative Models

Multiclass Logistic Regression - University at Buffalo

Probabilistic Discriminative Models •Generative vsDiscriminative 1.Fixed basis functions in linear classification 2.Logistic Regression (two-class) 3.Iterative Reweighted Least Squares (IRLS) 4.Multiclass Logistic Regression 5.ProbitRegression 6.Canonical Link Functions 2 Machine Learning Srihari

  Model, Logistics, Regression, Logistic regression

Machine Learning Basics: Estimators, Bias and Variance

Machine Learning Basics: Estimators, Bias and Variance Sargur N. Srihari srihari@cedar.buffalo.edu ... • To distinguish estimates of parameters from their true value, a point estimate of a parameter θ is represented by • Let {x(1), x(2),..x(m)} be m independent and

  Machine, Parameters

The Hessian Matrix - University at Buffalo

Diagonal Approximation • In many case inverse of Hessian is needed • If Hessian is approximated by a diagonal matrix (i.e., off-diagonal elements are zero), its inverse is trivially computed • Complexity is O(W) rather than O(W2) for full Hessian 7

  Matrix, Diagonal, Diagonal matrix

Backpropagation - University at Buffalo

Machine Learning Srihari Matrix Multiplication: Forward Propagation •Each layer is a function of layer that preceded it •First layer is given by z =h(W(1)T x +b(1)) •Second layer is y = σ(W(2)T x +b(2)) •Note that W is a matrix rather than a vector

Machine Learning Basics: Supervised Learning Algorithms

Deep Learning Probabilistic Supervised Classification Srihari • If we only have two classes we only need to specify the distribution for one of these classes – The probability of the other class is known – Linear regression has a closed-form solution – But …

  Learning

Gaussian Distribution - Welcome to CEDAR

• For a multivariate Gaussian distribution N(x| µ,Λ-1) for a D-dimensional variable x – Conjugate prior for mean µ assuming known precision is Gaussian – For known mean and unknown precision matrix Λ, conjugate prior is Wishart distribution – If both mean and precision are unknown conjugate prior is Gaussian-Wishart

  Distribution, Multivariate, Gaussian, Gaussian distribution, Multivariate gaussian distributions

Gaussian Derivatives - University at Buffalo

• Slice the surface with horizontal planes which the locus of points with the quadratic form. INFORMATION THEORY. Relative Entropy. ... great generality, and it is useful when we seek to know whether something other than the assumed case …

  Panels, Great

Iterative Reweighted Least Squares

•Derivative has the form •Setting equal to zero and solving we get Machine Learning Srihari 4 y(x,w)=w j ... 3.Gradient 4.Hessian 5.Newton-Raphsonupdate …

  Derivatives