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3. Bayesian Statistics and regularizationContent3. Bayesian statistics and regularization.3.1 Underfitting and overfitting.3.2 Bayesian statistics and regularization.3.3 Optimize cost function by regularization.3.3.1 regularized linear regression.3.3.2 regularized Logistic regression.3.4 Advanced Optimization.3.1 underfitting and overfittingThe linear regression model and logistic regression model have been studied before, and they have been applied i
did you not mention? A: The JVM is an unusually complex thing, writing a brick book is not too much, there are a few to explain:Chang (Constant pool): The area in which the constants in the program are stored sequentially and indexed. For example, int i = 100, this 100 is placed in the constant pool.SecurityManager: Provides security controls for Java runtime to prevent malicious attacks, such as specifying read files, write file permissions, network access, create processes, and so on, Class l
a development set (validation set)Validate cross-validation with a model verification methodLeave a validation (for early)A certain percentage of random sampling is used as a training set, leaving the usual proportion of 7 3 as a validation set, but the performance of the model is unstable due to the uncertainty of the validation set random samplingCross-validation (leave an advanced version of authentication)The average result is obtained after leav
another feature of the library Numarray of the same nature, and added other extensions and developed the NumPy. NumPy is open source and co-maintained by many collaborators to develop.2 Matplotlib Brief IntroductionMatplotlib is a library of very similar MATLAB environments that generate publishing quality data. The user can output the data in a pop-up window as a raster format (PNG, TIFF, JPG) or as a vector file (e.g. EPS, PS). Matlab users are familiar with the graphics types and syntax for
machine learning algorithms.In this section, we mainly introduce the use of naive Bayesian method for the classification of text, we will use a set of tagged categories of text documents to train naive Bayesian classifier, and then to the unknown data instances of the category prediction. This method can be used as a filter for spam messages.Data setThe data of this experiment can get a set of news informa
SAS graphical user interfaces help you build machine-learning models and implement an iterative machine learning process. You don ' t have a advanced statistician. Our comprehensive selection of the machine
Tags: 9.png update regular des mini RAC spam ORM ProofOrganize the machine learning course from Adrew Ng week3Directory:
Two classification problems
Model representation
Decision Boundary
Loss function
Multi-Classification problem
Over-fitting problems and regularization
What is overfitting
How to resolve a fit
Regularization method
Tools used: NumPy and MatplotlibNumPy is the most basic Python programming library in the book. In addition to providing some advanced mathematical algorithms, it also has a very efficient vector and matrix operations function. These are particularly important for computational tasks for machine learning. Because both the characteristics of the data, or the batch
Machine learning methods can be divided into generative and discriminative methods.
Generative model: assume that the input is X and the category label is Y. The generative model estimates the joint probability P (X, Y) Because samples can be generated based on the joint probability.
Discriminative model: assume that the input is X and the category label is Y. The discriminant model estimates the conditiona
according to this parameter estimation and the sample calculation category distribution Q.3 The extremum of the nether function is obtained, and the parameter distribution is updated.4 iterations are calculated until convergence.Say Ah, the EM algorithm is said to be a machine learning advanced algorithm, but at least for the moment, it is still easy to understa
: One-to-multiple
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Sometimes the problem is not as simple as determining whether a patient's tumor is malignant or benign. For example, determining whether the weather is sunny, cloudy, raining, Or snowing is necessary. We can use a line to separate binary classification. What about multiclass classification?
There is a simple method, that is, to separate only one category at a time. There are several categories to construct several decision edge, that is, severalH (x):
In th
First, cross-validation.Cross-validation (validation) is an evaluation of statistical analysis, machine learning algorithms for data sets independent of the training data generalization ability (generalize), can avoid overfitting problems.Cross-validation generally needs to be as satisfying as possible:1) The proportion of the training set should be enough, generally more than half2) uniform sampling of tra
Omit the use of octave end, later use to see itWeek Three:Logistic Regression:For 0-1 categoriesHypothesis representation:: Sigmoid function or Logistic functionDecision Boundary:Theta's Transpose * small x>=0 is boundaryMay:non-linear decision boundaries, constructing the polynomial of XCost function:Simplified cost function and gradient descent:Because Y has only two values, merging:To find the least biased guide:(The denominator should be ignored)Advanced
programThe example comes from the Wunda machine learning programming problem. The sample is the same as the digital recognition of multiple classifications in logistic regression.1, calculate the loss function, and gradientfunction [J Grad] = nncostfunction (Nn_params, ... input_layer_size, ... Hidden_layer_size, ... num_labels, ... X, Y, lambda) Theta1 = reshape (Nn_param
Here is still to recommend my own built Python development Learning Group: 483546416, the group is the development of Python, if you are learning Python, small series welcome you to join, everyone is the software Development Party, not regularly share dry goods (only Python software development-related), Including a copy of my own 2018 of the latest Python advanced
and linear regression appear to be the same:But its hypothetical function is different.Linear regression assumption function:Logical regression assumption function:6. Advanced Optimization
In addition to the gradient descent method, there are conjugate gradient method, BFGS (variable scale method) and L-BFGS (limited variable scale method), the advantage of these three algorithms is not to manually select the lea
following function to represent its cost function average (i.e. empirical risk)The best model is to calculate a set of θ values so that J (θ) is the smallest, and the gradient descent method can be used here as well, and it is amazing that the gradient function here is the same as the linear regression model. I have specifically proved that interested students point here: Machine learning-logic regression
posterior probability of the obtained implicit parameter is used to estimate the traditional likelihood function and correct the required parameter. Iteration until the two parameters are the same
In fact, it can be simply understood that we do not know the model parameters (such as Gaussian distribution) in unsupervised clustering ), at this time, we will randomly assign a value to the undetermined parameters (U and ó) of the model ). Then we can calculate the data that belongs to that catego
Author: Thuy T. Pham
Selected from the Heart of Kdnuggets Machine compilation participation: Wu Yu
Artificial intelligence is becoming the basic technology for a new generation of technology change, but developing artificial intelligence programs for their applications and businesses from scratch is expensive and often difficult to achieve the performance they want, but fortunately we have a large number of Ready-to-use APIs available to use. These A
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