I'm glad to have won the hackathon championship this time! The accuracy of our music prediction algorithm reaches RMSE = 13.24598.
The implicit feedbacks of SVD ++ did not play a major role this time. On the contrary, 86 feature columns in words are of great help and used in logistic regression. In addition, the combination of various profiles, items, and artist of users also brings good results.
The competition is described as follows:Competition go
columns. No row of data represents the probability that a sample belongs to each category.
"Rank:pairwise" –set xgboost to does ranking task by minimizing the pairwise loss
(2) ' eval_metric ' The choices is listed below, evaluation index:
"Rmse": Root mean square error
"Logloss": Negative Log-likelihood
"Error": Binary classification Error rate. It is calculated as # (wrong cases)/# (all cases). For the predictions, the evaluation w
1 Learning Goals:
Learn the basic TensorFlow concept
Using classes in TensorFlow LinearRegressor and predicting the median house value of each city block based on a single input feature
Estimating the accuracy of model predictions using RMS error (RMSE)
Improve model accuracy by adjusting the model's hyper-parameters
Note: Data is based on California State 1990 census data.2 settingsYou first need to load the necessary librar
This article introduces the content of the detailed classification evaluation indicators and regression evaluation indicators and Python code implementation, has a certain reference value, now share to everyone, there is a need for friends to refer to.
1. Concept
Performance measurement (evaluation) indicators, the main divided into two major categories:1) Classification Evaluation Index (classification), main analysis, discrete, integer. Specific indicators include accuracy (accuracy rate), pre
Treeclusteringrecommender (model, clustersimilarity, 10);Note that the similarity between the two cluster is defined by the clustersimilarity.The similarity between cluster and nearestneighborclustersimilarity is optional.Spit Groove:For the selection of algorithms, we are actually going to hook up with the target we want to recommend. Why the recent academia to SVD that system of algorithms so fire, what lda,plsa various algorithms, in fact, because Netflix's requirements are to optimize the
variance becomes square meters, more difficult to compare.4, RMS error (Rootmeansquarederror, RMSE) ≈ standard deviationThis is the square root of the mean square error, which represents the discrete degree of the predicted value, also called the standard error, the best fitting case is. The RMS error is also one of the comprehensive indexes of error analysis.Advantages: standardized mean variance is standardized to improve the mean variance, by calc
should be compared to the item I hit the score of 0.5 points, it is 2.5 points.Because the thought is so simple, so we come to practice a, of course, here is the most simple implementation, just to detect how the algorithm effect ... Data set is the same as the above blog, with a small data set inside the Movielens, which has 1000 users of 2000 items scored, 80% for training, 20% for testing.The specific code is as follows:#include The experimental results are as follows:In the test set on the
deviations.I used the paper "A Guide to Singular Value decomposition for collaborative Filtering, a single-machine version of SVD matrix decomposition Prediction Score is realized.Https://github.com/linger2012/svd-for-recommendation-implemented-by-javaThe loss function used isSolution with SGD, the model is updated once for each known User-item score.1000-time traversal training set, for the test set of Rmse can reach 0.96, is still good.The data set
, the range of cosine similarity is also between 1 and + 1. So we can also get it normalized to between 0 and 1.The time based on the calculation of item similarity will increase with the increase of the number of items, and the time complexity based on the user's similarity will increase with the increase of the number of users.The evaluation index of the recommended engine system is an indicator called the minimum RMS error (RMSE), which first calcu
maximum likelihood. The difference between the two was asked when interviewing Ali, then blurted out a classification is a return, but the deep meaning may be one is iterative solution, one is directly solved. Hope Advice4, How to optimize the model? How to evaluate the model good or bad? A: Model optimization mainly from the data and model two aspects, according to specific problems, such as over-fitting and too little data volume can be considered to increase the amount of data. model evaluat
Classification Model Assessment:
indicator
Description
Scikit-learn function
Precision
Precision Degree
From Sklearn.metrics import Precision_score
Recall
Recall rate
From Sklearn.metrics import Recall_score
F1
F1 value
From Sklearn.metrics import F1_score
Confusion Matrix
Confusion matrix
From Sklearn.metrics import Confusion_matrix
ROC
ROC Curve
From Sklearn.metrics Imp
be one of the FO llowing arguments:% * ' dataelements ' (initialization by the signals themselves), or:%
* ' Givenmatrix ' (initialization by a given matrix param.initialdictionary). % (optional, see Initializationmethod) initialdictionary,...% If the initialization method% Is ' Givenmatrix ', this is the matrix That'll be used. % (optional) truedictionary, ...% if specified, in each% iteration the Differe
nCE between this dictiona
x can be:
where Ru (1XN) is the first line of R, RI (1XM) is column I of R, I is the unit matrix of KXK. Iterative steps: First randomly initialize y, update x with the formula (3), and then update y with the formula (4) until the RMS error becomes RMSE small or the maximum number of iterations is reached.
Als-wr
The model mentioned above is suitable for solving scenarios where there is a definite scoring matrix, but in many cases the user does not
red and 5 nearest neighbors). Figure 4 shows the reduced data set. The cross is a neural network rule (3,2) of class outlier values (all of these instances belong to other classes); The square is the prototype and absorbs the empty circle of the point. The lower-left corner shows the class exception, the prototype, and the number of all three-class absorbed points. The number of prototypes varies from 15% to 20% in the different categories in this example. Figure 5 shows that the prototype 1NN
Introduction to Linear regressionAs shown, if the arguments (also called independent variable) and the dependent variable (also called dependent variable) are drawn on two-dimensional coordinates, each record corresponds to a point. The most common application scenario for linear back-regulation is to use a straight line to fit a known point and predict its Y value for a given x value. And all we have to do is find a suitable curve, which is to find the right slope and the longitudinal moment.SS
recommendation system called the latent factor (latent Factor) algorithm. This algorithm is in Netflix (yes, with big data to hold fireThe recommended algorithm for the company of the House of Cards is the first to be used in the film recommendations. This algorithm in practical applications than now ranked first in the Tai original LangThe algorithm error (RMSE) introduced will be much smaller and more efficient. I only use the underlying matrix kno
original algorithm, you will be amazed by the increase in the effect.
The dual ASVD prediction formula:
Here R (i) represents the user set that commented on the product I, and N (i) represents a collection of users who have browsed the product I but have no comments. Because of the large number of users, so the dual ASVD will occupy a lot of space, here need to make a choice.
The dual svd++ prediction formula:
Here n (i) represents a collection of users who have had behavior (browsing or sc
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