machine learning

iQiyi user retention forecast

User behavior sequence modeling iQiyi user behavior sequence modeling Article directory User behavior sequence modelingPreface1. Competition background2. Feature extraction1. User behavior sequence feature extraction2. User attribute feature extraction 3. Modeling4. Summary Preface The user retention prediction competition organized by iQiyi predicts how many days users will log into the app in th... »

Bellman Optimality Equation

Bellman optimal equation Table of contentsReview + SupplementLogical scene setup Bellman optimal equationOptimal strategy and optimal value functionoptimal state value functionOptimal state-action value function A small digression – maximum/expected valuesThe relationship between the maximum value and the expected value The relationship between optimal strategy and two value functionsBellman... »

Machine Learning | 3. Bayesian Classifier

1. Basic concepts The Bayesian classifier is the classifier that has the smallest probability of classification error among various classifiers or the smallest average risk at a given cost in advance. Its design method is one of the most basic statistical classification methods. The classification principle is to use the Bayesian formula to calculate the posterior probability of an object through ... »

Backtrader Quantification & Backtesting 2 – Read Pandas data in the strategy and add more custom data columns to the strategy

Article directory Backtrader reads Pandas data set basicsGet data information in the strategyCustomize the data set to expand more columns of data Backtrader reads data official documentation: Backtrader reads Pandas data set basics Using Backtrader’s built-in classesbacktrader.feeds.PandasDataAfter reading the dataframe data, the existing data column na... »

I want to simply write nce and infonce

Understand the conceptual distinction between nce and info nce Why is there ncence plan: does not countWhy is there infonceSo what is the relationship between infonce and nce?Reference article I have been looking at the derivation of infonce in the past two days, and I feel very confused. Today I feel like I understand it clearly, so I will write it down and discuss it with everyone. Why is there ... »

Pandas merge csv files

Scenes: It is troublesome to deliver multiple csv files in the project. Use pands.merge to merge them into one csv file. Code: code show as below #-*-coding:utf-8-*- import pandas as pd import numpy as np #Read csv file a = pd.read_table("a.csv",sep="\s+") b = pd.read_table("b.csv",sep='\s+') c = pd.read_table('c.csv',sep='\s+') d = pd.read_table("d.csv",sep='\s+') e = pd.read_table("e.csv",sep='\... »

Fuzzy inference study notes and examples

Fuzzy reasoning fuzzy setmembership functionFuzzy set operationsalgebraic operationsFuzzy relationship and synthesis of fuzzy relationshipSynthesis of Fuzzy RelationshipsFuzzy reasoningmulti-condition reasoning“Fuzzy decision-making”Application of fuzzy reasoning fuzzy set 1. DefinitionDomain of discourse: all objects UElements: each objectSet: elements with the same attributes and cer... »

Detailed explanation of K-means clustering algorithm + Python code example

Table of contents Preface 1. Cluster analysis 2. K-means principle 1. Distance measurement algorithm Euclidean distance (Euclidean distance) manhattan distance Chebyshev distance 2. K-means algorithm idea 3. Implementation of K-means algorithm step1:Select K value 1.Elbow method python code: 2.Contour coefficient method python code: step2: Calculate initialization K point step3: iterative calculat... »

[Installation of Keras environment]

Keras installation 1 Introduction2-Create a virtual environment3-tensorflow and keras installation4-Error log-waiting for resolution 1 Introduction 1. Keras needs to run on TensorFlow, so tensorflow must be installed first.2. Tensorflow can only run in python versions prior to 3.7, so you need to create a virtual environment based on python 3.6 first. 2-Create a virtual environment Open anaconda p... »

Machine learning basic HMM model (hidden Markov)

Article directory 1. Markov chain1 Introduction2. Classic examples3. Summary 2. Introduction to HMM1. Simple case2. Three basic questions 3. Basics of HMM model1. What kind of problems require HMM models?2. Definition of HMM model3. An HMM model example4. Generation of HMM observation sequence5. Three basic issues of HMM model 4. Forward-backward algorithm to evaluate observation sequence probabil... »

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