Experimental purposes
Recently intend to systematically start learning machine learning, bought a few books, but also find a lot of practicing things, this series is a record of their learning process, from the most basic KNN algorithm began; experiment Introduction
Language
Vi. more hyper-parameters in grid search and K-nearest algorithmVii. Normalization of data Feature ScalingSolution: Map all data to the same scaleViii. the Scaler in Scikit-learnpreprocessing.pyImportNumPy as NPclassStandardscaler:def __init__(self): Self.mean_=None Self.scale_=NonedefFit (self, X):"""get the mean and variance of the data based on the training data set X""" assertX.ndim = = 2,"The dimension of X must be 2"Self.mean_= Np.array ([Np.mean (X[:,i]) forIinchRange (x.shape[1]))
(a) KNN is still a supervised learning algorithmThe KNN (K Nearest neighbors,k nearest neighbor) algorithm is the simplest and best understood theory in all machine learning algorithms. KNN is an instance-based
point with the smallest distance
Volteilabel = lables[sorteddistindicies[i]]
Classcount[volteilabel] = classcount.get (Volteilabel, 0) + 1
sortedclasscount = sorted (Classcount.iteritems (), Key=operator.itemgetter (1), reverse=true) return
sortedclasscount[0][0]
v. Summary
AdvantagesThe KNN algorithm itself is simple and effective, it is a lazy-learning algorithm. There is no nee
KNN (K Nearest Neighbor) for Machine Learning Based on scikit-learn package-complete example, scikit-learnknn
KNN (K Nearest Neighbor) for Machine Learning Based on scikit-learn package)
Scikit-learn (sklearn) is currently the mos
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Catalogue [−]
Iris Data Set
KNN k Nearest Neighbor algorithm
Training data and Forecasts
Evaluation
Python Code implementation
This series of articles describes how to use the Go language for data analysis and machine learning.
Go
I. OverviewK Nearest neighbor (k-nearest NEIGHBOR,KNN) classification algorithm is a theoretically mature method and one of the simplest machine learning algorithms. The idea of this approach is that if a sample is in the K most similar in the feature space (that is, the nearest neighbor in the feature space) Most of the samples belong to a category, then the sam
) Print("the results of the classification are:,", Classifyresult)Print("The original result is:", Datinglabels[i])if(Classifyresult! =Datinglabels[i]): Errorcount+ = 1.0Print("the rate of error is:", (errorcount/float (testnum))) ## #预测函数defClassifyperson (): Resultlist= ['I don't like it at all.','There was a loss like','Grey often likes'] Percenttats= Float (Input ("How much time does it take to play video?")) Miles= Float (Input ("how many frequent flyer miles are earned each year?"))
First, K Nearest Neighbor Algorithm FoundationKNN-------K-Nearest neighbor algorithm--------K-nearest NeighborsThought is extremely simpleLess applied Mathematics (nearly 0)Good effect (disadvantage?) )Can explain many of the details of the machine learning algorithm use processA more complete process for characterizing machine
recently in the "Machine learning actual Combat" this book, because I really want to learn more about machine learning algorithms, coupled with want to learn python, in the recommendation of a friend chose this book to learn. A. An overview of the K-Nearest neighbor algorithm (KNN
-dimensional look at its truth:Since we have already written the KNN code, we just need to invoke the line. People who have learned about machine learning should know that many sample data should be normalized before the generation algorithm, where we normalized the data in the [0,1] range, normalized as follows:Where Max is the maximum value of OldData, Min is t
"Machine Learning Algorithm Implementation" series of articles will record personal reading machine learning papers, books in the process of the algorithm encountered, each article describes a specific algorithm, algorithm programming implementation, the application of practical examples of the algorithm. Each algorith
size as the input matrix.>>> Import knn>>> Reload (KNN) Six, the test algorithmone of the most important tasks in machine learning algorithms is to evaluate the correctness of the algorithm, usually we train the classifier with 90% of the existing data, and use the remaining 10% data to test the classifier to detect t
=1: , M is the total number of data categoriesWhen the data sample volume n tends to infinity, m=2:;It is shown from the formula that KNN algorithm is better than 1-NN algorithm because it reduces the lower bound of error. And with the increase of K, P_KNN asymptotic to the optimal error rate p_b; in fact, when k->∞ (but still accounted for a small portion of the sample total N), the KNN algorithm is approa
K-Nearest-neighbor algorithm for machine learning (KNN algorithm)
first, the conceptK-Nearest Neighbor algorithm is a simple machine learning method based on the distance between different eigenvalues. This paper simply introduces the next
points with the minimum distance from the current point;4. Determine the frequency of the category where the first K points are present5. Return to the category with the highest frequency of the first K points as the current point of the forecast classificationThe KNN algorithm for Python code implementationdef KNN (InX, DataSet, labels, k): datasetsize = dataset.shape[0] #shape [
applied to the numerical attribute, for the ordinal attribute can be transformed to a numerical type, the nominal attribute normalization is also better, but the two-dollar attribute may not be very good. Main advantages and Disadvantages:Advantages: High accuracy, insensitive to noise, no data input assumptions requiredCons: High complexity of time and space, need to determine K value (k value determination may require a lot of experience)Here is the implementation of the
KNNAlgorithmIt is an excellent entry-level material for machine learning. The book explains as follows: "There is a sample data set, also known as a training sample set, and each data in the sample set has tags, that is, we know the correspondence between each piece of data in the sample set and its category. After entering new data without tags, compare each feature of the new data with the features corres
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