gradient descent algorithm is the simplest and most direct method to solve the optimization problem. The gradient descent method is an iterative optimization algorithm for optimization problems:The basic steps are:1) Randomly select an initial point2) Repeat the following procedure:Determine the direction of descent:Select Step SizeUpdate:Until the termination condition is metThe specific process of the gradient descent method is as follows:2. Optimization in function spaceThe above is the sear
differences between the learners, such an integration algorithm will have better results, but in fact, accuracy and diversity are often conflicting, This requires us to find a better critical point to ensure the effectiveness of the integration algorithm. Depending on how the individual learner is generated, we can divide the integration algorithm into two categories:1) There is a strong dependency between individual learners, it is necessary to serialize the generated serialization method, thi
decision tree and neural network. The existence of dependency between individual learners in a homogeneous learner can be divided into two categories, the first is the existence of strong dependency between individual learners, a series of individual learners need to be serial generation, the representative algorithm is the boosting series algorithm, the second is the individual learners there is no strong dependency relationship, A series of individ
=2,y=2, using the above formula to launch the SAT (x, y), compares the SAT (x, y) you get on paper.After the integral graph is obtained, the calculation of the pixels in the rectangular region will be done with only four lookups and subtraction operations, as shown in 3:Figure 2: Calculation of the pixel value of the rectangular region in the integration graphAssuming that the four vertices of region D are a,b,c,d, the pixels within the region D are:It can be seen that the integral graph can acc
Elasticlunr.jsProject Address: http://elasticlunr.com/Code Address: Https://github.com/weixsong/elasticlunr.jsDocument Address: http://elasticlunr.com/docs/index.htmlElasticlurn.js is a lightweight full-text search engine in Javascript for browser search and offline search.Elasticlunr.js is developed based on Lunr.js, but more flexible than lunr.js. Elasticlunr.js provides query-time boosting and field search.Elasticlunr.js is a bit like SOLR, but muc
Rattle implementation of AdaBoost algorithmThe boosting algorithm is a simple, efficient and easy-to-use modeling method. The AdaBoost (Adaptive lifting algorithm) is often referred to as the best-available classifier in the world.The boosting algorithm builds multiple models using other weak learning algorithms, adds weights to objects that have a large impact on the data set, creates a series of models, a
. Integrated learning-Individual learner (question 1)
The first problem with integrated learning is how to get a few individual learners. Here we have two options.
The first: Individual learner is a kind of, such as the decision tree individual learner, or the neural network of individual learners. (Application is the most extensive)
The most common models used by homogeneous individual learners are cart decision tree and neural network.
There are two kinds of homogeneous individual learners acc
"Young Mans, in the mathematics you don ' t understand things. You just get used to them. "
Xgboost (eXtreme Gradient boosting) algorithm is an efficient implementation version of Gradient boosting algorithm, because it shows good effect and efficiency in application practice, so it is widely admired by industry.To understand the principle of the xgboost algorithm, we first need to understand the
;
(5) The algorithm is easy to understand;
(6) can be processed in parallel.
Disadvantages.
(1) The classification of small data sets and low dimensional datasets may not be very good results.
(2) The speed of execution is faster than boosting, but it is much slower than a single decision tree.
(3) There may be some very small differences in the tree, drown some of the right decisions.1.2 Build Step Introduction
1, from the original training data se
I. About the origins of the boosting algorithmThe boost algorithm family originates from PAC learnability (literal translation called Pac-Learning). This set of theories focuses on when a problem can be learned.We know that computable is already defined in computational theory, and that learning is what the PAC learnability theory defines. In addition, a large part of the computational theory is devoted to the study of the problem is computable, and
In the summary of integrated learning principle, we discuss whether there are two kinds of dependencies between the individual learners, the first one is the strong dependence between individual learners, and the other is that there is no strong dependency between individual learners. The former representative algorithm is the boosting series algorithm. In the boosting series algorithm, AdaBoost is one of t
When I recently made a mobile-phone page, I encountered a strange problem: The font display size is inconsistent with the size specified in the CSS. You can view this demo (remember to open chrome DevTools).As shown, you can find that the originally specified font size is 24px, but the final calculation is 53px, see this bizarre result, my heart cursed a sentence: What a ghost!Then began to troubleshoot the problem: A label caused? One of the CSS causes? Or a certain sentence JS code caused by.
When I recently made a mobile-phone page, I encountered a strange problem: The font display size is inconsistent with the size specified in the CSS. You can view this demo (remember to open chrome DevTools).As shown, you can find that the originally specified font size is 24px, but the final calculation is 53px, see this bizarre result, my heart cursed a sentence: What a ghost!Then began to troubleshoot the problem: A label caused? One of the CSS causes? Or a certain sentence JS code caused by.
any given weak learning algorithm, can it be promoted to strong learning algorithm? If they are equivalent, It is only necessary to promote the weak learning algorithm to strong learning algorithm, instead of looking for hard to obtain strong learning algorithm. The theory proves that, in fact, as long as the number of weak classifiers tends to infinity, the error rate of the combination of the strong classifiers will tend to zero.Weak Learning Algorithm---Recognition error rate is less than 1/
Http://www.cnblogs.com/hrhguanli/p/3932488.htmlBoosting Brief introduction
Classification is often used to classify multiple weak classifiers into strong classifiers, collectively referred to as Integrated Classification (Ensemble method). A simpler method, such as a bagging before boosting, is to train a weak classifier from a sample collection of the population, and then use multiple weak classifiers to voting, and finally the result is the winning
A. Xgboost Introduction
Xgboost (EXtreme Gradient boosting) is an efficient, convenient and extensible machine Learning Library based on the GB (Gradient boosting) model framework. The library was started by Chen Tianchi in 2014 after the completion of the v0.1 version of Open source to Github[1], the current latest version is v0.6. At present, in all kinds of related competitions can see its appearance, su
' $.Sampling a set of B Bootstrap samples $D _1, D_2, ..., d_b$, training a base learner $T _b (x) $ for this B sample set, together with these base-based learners to make decisions. In the decision-making, the voting method is usually used in the classification task, if the two categories of votes, the simplest way is to randomly select one, whereas the regression task generally uses the simple averaging method. The entire process is as follows:In this paper, we give the learning algorithm of
Regionlets for Generic Object Detection, regionletsgeneric
Regionlets for Generic Object Detection
This article is the translation and self-understanding of this article, the article: http://download.csdn.net/detail/autocyz/8569687
Abstract:
For general object detection, the current problem is how to use a relatively simple calculation method to solve the recognition problem caused by the angle change of the object. To solve this problem, a flexible object description method must be required, an
Copyright Notice:This article is published by Leftnoteasy in Http://leftnoteasy.cnblogs.com, this article can be reproduced or part of the use, but please indicate the source, if there is a problem, please contact [email protected]. can also add my Weibo: @leftnoteasyObjective:Decision tree This algorithm has many good characteristics, for example, the training time complexity is low, the prediction process is relatively fast, the model is easy to display (easy to get the decision tree into a pi
the data. The second principal component captures the remaining variance in the data, but has a variable that is not related to the first component. Similarly, all successive principal components (PC3, PC4, etc.) capture the remaining variance, which is not related to the previous component.Figure 7:3 Primitive variables (genes) reduced to 2 new variables called principal components (PCS)Integrated Learning TechnologyCombination means to improve results by voting or averaging, combining the res
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