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Questions tagged [multi-class]

Multiclass classification is a classification task in which there are more than two classes. It is also called multinomial classification.

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Improveness given a certain AUPRC

I am training a machine learning model (Random Forest) for a multiclass problem (64 classes) in which most of them are highly imbalanced. That's why I am using mainly F1 score for checking the model's ...
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25 views

Sequence Classification Machine Learning Methods

I know that this question might have been asked before but I did not find any response so far. My problem is that I am doing Multi-class sequence classification with Stacked LSTM (3 layers) using ...
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Naive Bayes missclassification rate across classes

I have a dataset with income, age sex and education as categorical features. I used R to create a Naive Bayes classifier as follows: income ~ age + sex + education. I got the following a-priori and ...
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Is there any strategy for validating the result of a general comparison between several confusion matrices?

Disclaimer: Recently we have developed a python library named PyCM specialized for analyzing multi-class confusion matrices. A compare system has been added in <...
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54 views

Evaluating Unbalanced Multiclass Classifiers: Which Tests to Use? [closed]

I am looking for some comprehensive instructions and ideally out of the box solutions (ideally for python) for evaluating different classifiers (which are already trained) for a multiclass ...
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14 views

Are these Multi-label document classification experiment steps sensible?

I plan to filter an input document using 4 different labels. Just for an example, a document discussing about movie summary needs to be labeled with 4 labels (Romance, Drama, Fiction, Hollywood). ...
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41 views

Improving Average F1 Score for Multiclass Classification

I'm trying to do a multiclass classification with h2o in R. I stacked a model with a RF, GBM and deeplearning. The accuracy is ok (~0.81), but the average F1 score is bad because class B has a very ...
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23 views

Is it possible to calculate the ROC_AUC score for a class in a multiclass problem that is not in the predicted array?

I was working on calculating the auc score for a multiclass problem and came across this problem. Suppose I have a data set with three classes [0,1,2] My test set is like this [0,1,2,0,0,2] My ...
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What measures of an ML algorithm's 'accuracy' are mostly consistent as the number of classes to predict into varies?

For a research project, I've got a bunch (N=507) of 20-second VR tracking data clips (6DOF x head and hands), each from a different participant. My goal is to predict the participant using a small ...
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125 views

SMOTE sampling for multi-class data

I have a classification problem with 4 distinct classes, but imbalanced data. ...
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0answers
8 views

Multiclass classification- dealing with clusters within classes?

I'm currently dealing with a problem where I'm trying to predict how much a value x will change over time given input variables and am bucketing this change into separate classes (ie -100 to -50%, -50%...
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15 views

Multiclass classifier with undefined prediction, how to calculate metrices

I build a multiclass classifier. I want the classifier to predict a few samples with little false positives, rather then many samples with lots of false positives. Therefore I want to choose a ...
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10 views

How to calculate precision-recall curve for multiple binary classifier for multiple classes

I am using autoencoder based multiple binary classifier for text regeneration each trained on data related to multiple classes. In other words, each classifier is trained to classify only one class. I ...
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Multiclass classification with a balanced dataset and one high-priority label

I have a balanced dataset for a multi-class classification problem with one high-priority label (this ought to be classified properly at all costs). How do I go about creating a workflow for this ...
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28 views

Is Multi-output Multi-Label classification possible for this merging problem?

I have programmed a game called cell wars where cells can capture other cells via merging. The image below shows the same board before merging (top) and after merging (below). Basically, overlapping ...
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17 views

Identifying Misclassifications

Let's say there's a process that takes in an observation X and assigns it to one of 3 classes: A, B, or C. It's believed that this process routinely assigns observations to class A when they should'...
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14 views

How to ensemble predictions from image classifier and text classifier?

I am doing multiclass classification based on images and text. I have predictions from both image classification and text. I am not sure how to combine them. Should I use probabilities as a feature to ...
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18 views

Machine Learning, which kind of classification should i use?

So im trying to make a ML classifier model to my data. My data has many X(variables [texts, integers, binaries etc.]) and 5 output(Y) information. In short, lets say i have 5 different places to put ...
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30 views

How to choose metrics for evaluating classification results?

Recently we have developed a python library named PyCM specialized for analyzing multi-class confusion matrices. A parameter recommender system has been added in version 1.9 of this module in order ...
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27 views

Intuition Behind One Vs. All Linear Least Squares Classification

I understand that in the one vs. all classification approach, we form $k$ discriminants, one for each of the $k$ classes and that $(w_k - w_j)^Tx + (b_k - b_j) = 0$ is the hyperplane decision boundary ...
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1answer
145 views

What is difference between accuracy_score() and cross_val_score()?

The problem I'm working on is a multiclass-classification. Have been reading through lot of articles and documentation, but not able to figure out which of Accuracy_Score or Cross_Val_Score should be ...
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1answer
39 views

Machine learning for product names

I have a machine learning challenge I may be over thinking. I have a set of 3.5 million products (not unique, there are multiple instances of each product). Each product has a "description" from it's ...
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118 views

SMOTE and ROSE methods in CARET (R) do not work for balancing a multi-class dataset

SMOTE and ROSE methods in CARET (R) do not work for balancing a multi-class data set. Specifically, ROSE throws an error telling that it needs two levels. It means that it does not work for multi-...
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2answers
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Which classification model should I choose and Why?

I am working on a research-based assignment where I suppose to build a 3-class (bad, medium, good) classification using SVM. The dataset provided is imbalanced. The train:test splitting ratio is 75:25 ...
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Is it possible to have a constent accuracy for my tensorflow network whatever is the iterations?

I am runing my tf NN composed by one input, one hidden and one output layers the number of hidden nodes if the half of total features number I have got the next table considering different learning ...
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12 views

Hierarchical vs multi-class, when to use what?

I am looking for suggestions from machine learning research perspectives about using hierarchical classifier vs multi-class classifier. For example, if I have to classify 3 classes, let's say, 2 ...
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1answer
27 views

Anyway i can improve this multi class classification result?

I am building a multi class classification model using SVM to predict the grade for essays. What can I do to improve the result especially for class 1 and class 3? Their precision and recall are ...
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1answer
228 views

Adjust thresholds in multi-class classification [duplicate]

I have trained a random forest classifier on a (highly-imbalanced) 3-class problem (A 1% of the data, B 96%, C 3%) and obtained probabilities for each of the three classes. Currently I assign an ...
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29 views

RFE-RF for non-ordinal multi-class problem using integer target variable

For a classification problem with numerical predictors and a categorical multi-class response I am trying to use Recursive Feature Elimination with Random Forests to identfy relevant features out of a ...
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1answer
67 views

Quadratic Weighted Kappa metric in H2O package for model performance

I am running a multiclassification problem and before I make a function by myself I was wondering if anyone knows of a pre built quadratic weighted kappa function in the h2o library.
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18 views

Logistic Regression(multi class) accuracy too small

I try to solve a problem with 3 features and 6 classes(label). The training dataset is 700 rows * 3 columns. I use one-Vs-all method, but I do not why the prediction accuracy is too small, just 24%. ...
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1answer
279 views

Multi-class Decision Forest vs Multi-class Decision Jungle

guys. I have been learning about machine learning using Azure ML service from Microsoft and my team and I have seen that there are some multi-class decision algorithms, the Forest and Jungle are ...
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358 views

Multi Layer Perceptron and multiclass classification in Python problem

i have a problem regarding MLP in Python, when i am making multiclassification i only take as an output one of the possible 4 classes. I tried a solution of instead using "predict", using "predict....
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39 views

Evaluating multiclass decision tree as a probability function

I have a problem where I am trying to estimate the transition probability within a state-diagram. For example, estimating the chances of transitioning from a happy mood to one of 3 possibilities (...
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42 views

High accuracy for single classes & low accuracy for multiclass classification

I was trying to do a multiclass-classification, where each sample belongs to one of the four classes. Now that I have a probability vector $(p_1^i,p_2^i,p_3^i,p_4^i)$ for each sample $i$ as my ...
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1answer
374 views

Imbalanced multiclass classification with many classes

I am working on a text classification project in which we have hundreds of (imbalanced) classes. Some characteristics of the data: We have examples of "bad" documents. Basically documents that don't ...
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21 views

What is a good performance index in multi-classification problem?

I'm performing a multi classification model exploiting different statistical learning methods. In particular, I'm performing a classification in 3 different classes. I'd like to know if there exists ...
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32 views

How to know if your decision tree model has overfitting or not?

I am using the DecisionTreeClassifier() of python and I am changing some tuning parameters to understand if my model has overfitting or no because when I exectue the following code without any ...
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23 views

Understanding model performance

I built a multiclass (and very imbalanced classes) classifier. When evaluating I found an average F1 of .98 and the classifier seems to be working rather well. However, on evaluating the ROC and ...
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167 views

CNN Flower recognition (5 classes) accuracy improvement

I have created a CNN for image recognition (Flower types - 5 classes) and am now considering model parameter changes to improve accuracy. The model (5 3*3conv + 4 2*2max pooling layers) attains ~60% ...
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22 views

How to group text categorical data basis on clustering?

So if I have text dataset where I have more than 50 categories. Sample: ...
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1answer
121 views

Summing predicted probabilities from logistic regression using 'one vs. rest'

I have a multiclass classification problem that I have solved using a 'one vs. rest' approach via binary logistic regression classifiers from Python's scikit-learn package. In my problem, there are 3 ...
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215 views

Simulate/Generate Data for Multinomial Logistic regression

How to simulate data for Multinomial Logistic regression? For Example i want to generate a high dimensional data set with 90 subjects and 500 independent predictors. The ratio of Classes should given ...
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216 views

How to manually balance unbalanced multi-class/multi-label data?

I have a multi-class and multi-label classification problem, i.e.: each sample can have more than one label associated to it and there is a total number of M ...
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1answer
53 views

Decision tree without the “tree”

I would like to construct something like a decision tree. However, instead of using "recursive partitioning" to build a tree, I would like to find an optimal set of "global" splits. For example, in a ...
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384 views

How to combine/aggregate classification accuracies from binary one-vs-one classifiers to get final accuracy equivalent a multiclass classifier?

Consider a 3 class data, say, Iris data. Suppose we want do binary SVM classification for this multiclass data using Python's sklearn. So we have the following ...
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9 views

Splitting strategy for a multiclass problem

I have a 16 class data , Indian Pines , of dimensions 145x145x200. From the data size , I am unable to gauge whether to do stratified splitting , random splitting , or plain train-test split , before ...
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715 views

How to implement one vs rest classifier in a multiclass classification problem?

I have a dataset which contains 750 data points with 8 classes in the target variable. I tried implementing simple machine learning models and also did hyperparameter tuning but they results were not ...
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1answer
284 views

ValueError: Requesting 3-fold cross-validation but provided less than 3 examples for at least one class. Any way to get away with this?

I am trying to perform multiclass classification on a 10 class dataset with around 650 data points. But whenever trying to run the code, it gives the above-mentioned error. Although, I understand what ...
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86 views

multi class logistic regression : $K-1$ regressors or $K$ regressors (softmax)?

I read that, in multiclass logistic regression, we have a pivot class $K$ and $K-1$ set of $\vec{w}$ weights, then, for the pivot class: \begin{eqnarray} P( C_K | \vec{x} ) &= 1- \sum_\limits{t=...