# Questions tagged [svm]

Support Vector Machine refers to "a set of related supervised learning methods that analyze data and recognize patterns, used for classification and regression analysis."

2,215 questions
Filter by
Sorted by
Tagged with
6 views

### The derivation of the RBF kernel to the inner product form, and what does this notation $\sum _{n_{1}+n_{2}+\dots +n_{k}=j}$ mean?

I have two questions regarding the following derivation: What does this notation $\sum _{n_{1}+n_{2}+\dots +n_{k}=j}$ mean in the following equation? How is it derived from step 3 to step 4, and from ...
5 views

### SVM decision boundary and resolving process with given simple value (1,1), (2,2) by hand [duplicate]

I'm beginner of SVM and have difficulty understanding SVM mechanism. Anybody help me explaning svm process with simple value (1,1), (2,2) and decision boundary?
1 vote
14 views

### Why am I getting 100% accuracy for SVM, Random-forest Classifier and Logistic Regression?

I'm using an existing disease prediction model to build a chatbot. While I was referring to the model I realized that it has an accuracy of 100%. I'm not quite sure how and why the accuracy is 100%. I'...
1 vote
17 views

### Why is the model getting 100% accuracy for SVM, Random-forest Classifier and Logistic Regression? [closed]

I'm using an existing disease prediction model to build a chatbot. While I was referring to the model I realized that it has an accuracy of 100%. I'm not quite sure how and why the accuracy is 100%. I'...
8 views

### SVM working with simple value [duplicate]

I'm beginner of SVM and have difficulty understanding SVM mechanism. Anybody help me explaning svm process with simple value (1,1), (2,2) and decision boundary?
7 views

### Fuzzy membership - Kernel SVM in R

I'm trying to perform a binary classification task using SVM with radial basis kernel in R and I want to assign fuzzy memberships to the datapoints. Already existing function in R packages such as ...
1 vote
26 views

### Support vector machine, complementary slackness and marginal hyperplane

One of the complementary slackness conditions for a support vector machine states that $$\alpha_i ( y_i (\langle w, x_i \rangle + b ) -1 ) = 0,$$ where $\alpha_i$ is the lagrange variable. One can ...
15 views

### What kernel to use for image classification from pre-trained CNN feature extractor

Suppose I have a pre-trained CNN feature extractor and I connect those to a soft margin SVM, what is the recommended kernel to use to replace $x_n^Tx$ in SVM? My dataset comprises of pictures of ...
15 views

### Why does SVM always find separating hyperplane in p>>N and avoid overfitting?

I have gene expression data with ~20,000 features and nearly 600 samples, with 5 classes of cancer. I used grid search with 5 fold CV to find the optimal kernel and regularization for SVM, and I found ...
795 views

### Averaging SVM and GLM results: sensible or stupid?

I have taken two different approaches to calculate probability: using a GLM and an SVM. They are giving slightly different results (which is understandable, they are completely different approaches). ...
36 views

### One-class SVM with single dimension and polynomial kernel

Context: I'm studying anomaly detection without prior experience in machine learning, although I'm a senior web developer. This article talks about the kernel trick and gives this example with single ...
8 views

### Would logistic regression/support vector-machine with l-2 regularization and early stopping regularization cause underfitting?

Would early stopping regularization combined with l-2 regularization or in logistic regression/support vector machine cause underfitting? Does a kernel-trick affect what combination of regularization ...
32 views

### How variable alpha changes SGDRegressor behavior for outlier?

I am using SGDRegressor with a constant learning rate and default loss function. I am curious to know how changing the alpha parameter in the function from 0.0001 to 100 will change regressor behavior....
1 vote
22 views

### Confusion matrix error [closed]

I have been trying to do support vector machine classification in R and confusion matrix has been showing the error even after changing into factors confusionMatrix(as.factor(yTestPred), as.factor(...
31 views

### Selection of informative examples of majority class for undersample using SVM

I have this idea in mind, but I am not sure how to implement it. Suppose I have an imbalanced data that I want to down-sample instances of majority class, such that it becomes equal in size to the ...
15 views

### Trying to predict the next ignition off for a vehicle

Overview: I have a dataset that captures 6 months of data for 1000 cars. Each car is represented by it's unique identifier. The data captures the exact timestamp when the car was turned ON and turned ...
17 views

### Is my use of Early Stopping appropriate in my model selection process?

My data is split into 80% train, 10% validation and 10% test. My dataset has three versions: i) Base dataset, ii) SMOTE adjusted version 1 and iii) SMOTE Adjusted version 2. I have run a 4 different ...
1 vote
17 views

### What kind of semi-supervised learning method should be used for a low quality data set?

Consider a binary classification problem, there are $1000$ samples in the data set, of which $500$ positive and negative samples each. Positive samples have the label $1$ and negative samples have the ...
39 views

### Why does linear SVM perform better than deep learning techniques on my problem?

I am doing a multiclass text classification problem. My data consists of tweets. I tried many variations of deep learning models (ex: LSTM, GRU and pre-trained word embeddings) and I also tried linear ...
30 views

### SVM: How to derive the KKT condition with soft margin term is quadratic?

I was reading the Introdunction to Data Mining (2013) when I came across this in section 5.5: $$f(\textbf{w})=\frac{||\textbf{w}||^2}{2}+C\left(\sum^N_{i=1}\xi_i \right)^k$$ I found similar ...
682 views

### Can correlation matrix be used as features in machine learning classification

Can I use correlation between the training data as features, and if possible how will I test the test data with the model coefficients I will try to explain more If the training data are ...
192 views

### Is there a Good Illustrative Example where the Hinge Loss (SVM) Gives a Higher Accuracy than the Logistic Loss

Vladimir Vapnik wrote: “When solving a problem of interest, do not solve a more general problem as an intermediate step. Try to get the answer that you really need but not a more general one.” ...
23 views

### Primal Problem of SVM

The primal problem of SVM is denoted as below. $$min_{w,b}\left(\phi \:\left(w\right)\right)=min_{w,b}\left(\frac{1}{2}w^Tw\right)$$ Subject to $$y_n\left(w^Tx_n+b\right)\ge 1,\:n=1,2,3,...,l$$ And If ...
12 views

### What's the effect of Heteroscedasticity in predictor variables for SVM classification?

It's usually a good practice as part of the modeling stage to apply transformations to all predictor variables so that they are stationary or in other words, that the statistical properties such as ...
359 views

### How can I mathematically represent the one-hot encoding?

If we have 5 classes and 3 inputs, let's say [C1, C2, C3, C4, C5] and [X1, X2, X3] then, If ...
1 vote
48 views

### How can I make sense of alpha values obtained from scikit-learn OC-SVM?

I am building a ML model that uses the OC-SVM for anomaly detection. For our cost function we require the alphas obtained from the OC-SVM. We use the OC-SVM of scikit-learn, which I assume is based on ...
1 vote
27 views

### Learning-Agnostic Evaluation of SVM Models

I am at a point where I want to evaluate existing SVM models. For this task I assume I have: SVM model (to make it easier let's say it's a scikit-learn one) Training Dataset that was used to learn (1)...
1 vote
87 views

### Square Root of kernel function validity [closed]

If k1(x,z) and k2(x,z) are valid kernels, then is k(x,z) a valid kernel, where k(x,z) = sqrt(k1(x,z)k2(x,z)) Prove using mercers theorem
69 views

### Proving validity of kernels

If k1(x,z) and k2(x,z) are valid kernels, then is k(x,z) a valid kernel, where k(x,z) = a1k1(x,z) - a2k2(x,z) (where a1, a2 > 0 are real numbers) I don't think this is true, but I am having trouble ...
1 vote
26 views

### SVC: why is at least one sample always exactly lying on the support vectors?

I don't really understand, why at least one sample is always exactly lying on the support vector(s). When assuming, that the dataset is exactly linearly seprable and considering the cost function of ...
1 vote
18 views

### Predicting negative class rather than target in SVM [closed]

I am trying to classify a target group from controls using a SVM. I am predicting probabilities, and noticed that when predicting the target class, the SVM performance was horrible (AUC ~0.2). This ...
18 views

### Effect of apparent correlation due to clustered data on performance of binary classifier

I am exploring possible features for a binary classifier, probably using a SVM, and have encountered an issue with correlation of features. I have chosen a number of features that may be of interest ...
12 views

### Significance Test for Linear Support Vector Machines [duplicate]

As we know, after applying a linear regression model to a continuous data set we carry out a significance test to each parameter βi associated with the predictor variable xi to check whether the ...
45 views

### Why are radial basis functions so different from classic inner product?

I was studying SVM with kernel tricks and it seems that the kernel is a modified dot product. A simple kernel would be $K(x,y) = <x,y>^2$. I understand how this is a modification of the dot ...
1 vote
30 views

### Is using SVC for detection problems is the right choice?

I have an NLP problem(fake news detection) and I used the code below, can I use svc for classification? and is my cross-validation accurate? ...
8 views

### Dummy coding with overlapping categories

Spotify has a structured dataset which contains song tracks with its associated audio features such as energy, speechiness (numeric data), whether there is explicit language in the lyrics (boolean), ...
23 views

### ValueError: Requesting n-fold cross-validation but provided less than n examples for at least one class

I have been training a text classifier to then later use to predict characters of a TV show. So far, my code looks like: ...