decision tree of machine learning algorithmWhat is a decision treeDecision Trees (decision tree) are simple but widely used classifiers. By training data to build decision tree, the unk
continue reading the article.
The decision tree is actually a way to divide the space with a hyperplane.CurrentThe space is split into two parts, for example, the following decision tree:
Divide the space into the following:
In this wayEach leaf node is in a non
. In data mining, we often use decision trees for data classification and prediction.
Helloworld of decision tree
In this section, we use decision trees to classify and predict iris data sets. Here we will use graphviz of the tree under sklearn to help export the
Learning is a step-by-step process. Let's first understand what a decision tree is. As the name suggests, a decision tree is used to make decisions and make judgments on a thing. How can we determine it? Why? It is a question worth thinking about.
See the following two simple examples:
Supervised Learning-classification decision tree (1)
Decision tree(Demo-tree)Is a basic classification and regression method. The tree structure can be considered as a set of if-else rules. The main advantage is that the classific
Here is an introduction to the previous decision tree algorithm.We have learned the whole method of decision tree before, and have a clearer understanding of its construction process. This time, the reading notes focused on the application of decision trees and the use of ma
Shen, C. Stone). These algorithmsCommon denominator: Both are greedy algorithms, top-down (top-down approach)Difference: Attribute Selection metric methods differ: C4.5 (gain ratio, gain ratio), CART (Gini index, Gini index), ID3 (information gain, information gain)2.5 How do I handle the properties of a continuity variable? Some data are continuous, unlike the above experimental data can be discretized representation. For example, according to the w
divide attributes with information entropy gain, refer to this brother's article: http://blog.csdn.net/alvine008/article/details/37760639If you don't understand it, take a look at the example below.Let's say I'm going to build a decision tree that automatically chose Apple, and for simplicity, I'll just ask him to learn the following 4 samples:[Plain]View Plainc
You need to write a data structure (refer to the topic title) to maintain an ordered series. The following operations are required:1. query the ranking of K in the interval2. query the value of the row named K in the interval.3. Modify the value of a certain bit.4. query the precursor of K in the range (the precursor is defined as less than X and the maximum number)5. query the successor of K within the range (defined as greater than X and the smallest number)Question: a
A decision tree, also known as a decision tree, is a tree structure used for classification. Each internal node represents a test of an attribute, each edge represents a test result, and the leaf node (leaf) represents a class) or class distribution. The top node is the root
A decision tree, also known as a decision tree, is a tree structure used for classification. Each internal node represents a benchmark test on a certain attribute, each edge represents a benchmark test result, and the leaf node (leaf) represents a class) or class distributio
Reprint Address: http://blog.csdn.net/w28971023/article/details/8240756 GBDT (Gradient boosting decision tree), also known as MART (multiple Additive Regression tree), is an iterative decision tree algorithm, which consists of multiple d
here. For example, when tossing a coin, the positive probability is 1/2, the negative probability is also 1/2, then the entropy of the process is:It can be seen that because the coin toss is a completely random event, its result is equal probability of the positive and negative, so it has high entropy.If we observe the direction of the final flight of the coin, then the probability of the last drop of the coin is 1, the probability of flying to the s
Decision TreeDecision tree model is a kind of tree structure, which is a process of classifying or returning instances based on feature. That is, according to a certain feature divides the data into several sub-regions (subtree), and then recursively divides the sub-region, until a certain condition is satisfied to stop dividing and as a leaf node, does not meet
by many business customers and practitioners in the data mining industry as a synonym for data mining.Regression analysis, which we often hear in data analysis, is a method of analysis that is often used to estimate and predict Regression. The so-called regression analysis, or simply regression, refers to the technology that predicts the correlation between multiple variables, and the application of this technology in data mining is very extensive.Decision TreeOf all the data mining algorithms,
decision tree can deal with missing values, while logical regression requires mining personnel to process missing data in advance. But in fact, the decision tree also needs to make some assumptions and process the missing values. For example, if a cart is missing, it is rep
, and a system became moreis orderly, the information entropy is lower, conversely, the more chaotic a system, the higher the information entropy. So information entropy can be thought of as an orderly system.A measure of the degree of\[h (x) =-\sum_{i=1}^{n} p_{i} log_{2} p_{i} \]Third, information gain information GainThe information gain is for one characteristic, that is, to see a characteristic, the system has it and the amount of information when it is not, bothThe difference is the amount
Decision Tree A decision node represents a sample test, which typically represents a property of a sample to be categorized, and the different test results on that attribute represent a branch; a branch represents a different value for a decision node. Each leaf node represents a possible classification result.Using th
array bucket, you can draw the order of the elements://size of the array src, that is, the number of elementsvoidBucketsort (unsignedint*src,unsignedintsize) { //Max is a macro that indicates that the element in SRC is not greater than or equal to a valueUnsignedintBucket[max] = {0 }; //"Throw the elements in the bucket." for(unsignedinti =0; I i)++Bucket[src[i]]; //to "pour out" the elements in the bucket .Unsignedintj =0; for(unsignedinti =0; I i) for(unsignedintx =0; x x) src[j++] =b
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.