Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [matlab]

The tag has no usage guidance.

0
votes
0answers
4 views

Poor performance for unbalanced dataset

Consider a dataset A which has examples for training in a binary classification problem. I have used SVM and applied the weighted method (in MATLAB) since the ...
0
votes
0answers
4 views

Deriving Dirichlet samples from gamma distribution

From wikipedia, it is written that you can generate dirichlet samples from the gamma distribution simply by normalizing the game samples. So in MATLAB, to get dirichlet samples, i would code it in ...
0
votes
0answers
5 views

Newton's method gradient and hessian formulation difficulties

Logistic regression Newton's Method Newton Method Lecture II In this picture the logistic regression cost function , Newtons Method and gradient and Hessian is defined. How to get this function that ...
0
votes
1answer
28 views

How can I increase the number of iterations per epoch in MATLAB?

I am training a deep learning network using MATLAB and would like to increase the number of iterations per epoch. Using trainingOptions ...
0
votes
0answers
19 views

Random Forest with cross validation using TreeBagger on Matlab

I'd like to do cross validation on a Random Forest model. I've tried using crossval but it doesn't work on TreeBagger. I tried using for loop, but I'm not sure it's correct: ...
1
vote
0answers
40 views

Using machine learning algorithm to approximate a matrix? [closed]

I don't know if this is a good question. I would like to use machine learning to approximate a matrix. For example, a very simple one as \begin{align} A=\begin{pmatrix} 1 &0 \\ 0& 2 \end{...
1
vote
1answer
17 views

How can I create a pixel labelled image for Semantic Segmentation?

I am following the Semantic Segmentation Examples tutorial by MathWorks. I understand that I can load pixel labeled images ...
0
votes
1answer
9 views

Methods for augmenting binary datasets

I have a small (~100 samples) dataset with roughly 20 features which are mostly binary, and a few are numeric (~5). I wanted to use methods for augmenting the training set and see if I can get better ...
0
votes
1answer
25 views

Graphically Speaking - how weight vector is perpendicular to hyperplane

why-is-weight-vector-orthogonal-to-decision-plane-in-neural-networks vector-orthogonal-to-hyperplane I wanted to visualize this by drawing a 3d plane where and the weight vector. By definition of ...
0
votes
1answer
16 views

Higher dimension data visualization in Matlab/Octave

I am working on sparse recovery for a classification task. I use Pine hyperspectral dataset which is a freely available dataset and this image contains 200 Dimension (Depth/channels/bands). In ...
0
votes
2answers
36 views

why nobody uses matlab [closed]

I wonder why most people now don't use matlab. I guess the reason is matlab is not free, so companies don't want to use it, then interviewees don't use it, then schools don't encourage it, then nobody ...
0
votes
1answer
20 views

Why the results from Matlab curve fitting function differ when using custom equation?

I'm using Matlab's curve fitting app, When I select Power fitting it returns values which perfectly describe the data but when I use the custom equation and enter ax^b as the equation it returns very ...
0
votes
0answers
42 views

How does `cvpartition` in Matlab work?

I have split my entire dataset X and the label set Y into Xtrain_val and ...
1
vote
1answer
31 views

Problem with calculating error rate for KNN

I am trying to validate the accuracy of my KNN algorithm for the movie rating prediction. I have $2$ vectors: $Y$ - with the real ratings, $Y'$ - with predicted ones. When I calculate Standard ...
1
vote
0answers
18 views

How can I combine images for Matlab deep learning?

I have a data set which consist a number of instances (of two-three different classes), and for each instance I have a handful of monochrome images. This handful of images have different resolutions (...
2
votes
0answers
117 views

Matlab: setting static iterations per epoch in a CNN

I'm building a convolutional neural network using Matlab's neural network toolbox. I have code designed to cross-train the network with different data sets, using the previous network's layers in ...
0
votes
0answers
72 views

Logistic Regression sklearn vs matlab Different Answers

Years ago I built a model in Matlab that used glmfit(X, Y, 'binomial, 'link', 'logit') and I am now trying to transfer the model to python using sklearn (i.e sklear.linear_model.LogisticRegression). ...
1
vote
1answer
125 views

Poor performance of SVM after training for rare events

I found out that Weighted SVM is a classification approach to handle class imbalance problem. My data set is highly imbalanced with rare event (minority class, labeled as 1) and the majority class (...
0
votes
1answer
49 views

Confusion regarding classification accuracy calculation and result

The total number of data points for which the following result is obtained = 1500. Out of which, I have 1473 labelled as 0 and the remaining 27 as ...
4
votes
3answers
216 views

Which Format is Faster, Matlab (.mat) or NumPy (.npy)?

I am working on a deep learning problem to detect cancer in images of size 250 x 250. I have hardware limitations and I have been running out of memory. I decided to convert my images to Matlab ...
1
vote
2answers
135 views

Terminology - cross-validation, testing and validation set for classification task

Confusion1) If k=10 then does this mean that 90% is for training and 10% for testing? So always we have k% for testing? ...
0
votes
2answers
84 views

Is ensemble learning using different classifier combination another name for Boosting?

For implementation I am following the Matlab code for AdaBoost. Based on my understanding, AdaBoost uses weak classifiers known as base classifiers and creates several instances of it. For example, a ...
0
votes
0answers
14 views

correspondence analyses in matlab to show presence/absence data in different locations

In MATLAB, I want to plot a PCA-type plot (I think) to show presence/absence of species in different locations so that points ...
2
votes
2answers
126 views

How to make sense of confusion matrix

Consider a binary classification problem with 0 labels denoting normal and 1 abnormal or rare. The number of instances with <...
3
votes
2answers
246 views

Why training and validation similar loss curves lead to poor performance

I am training a binary classification neural network model using matlab the graph that I got using 20 neurons in hidden layer is given below. the confusion matrix and graph between cross entropy vs ...
0
votes
1answer
81 views

How to quantify the performance of the classifier (multi-class SVM) using the test data?

I am working on a traffic sign recognition code in MATLAB using Belgian Traffic Sign Dataset. The dataset consists of training data and test data. I resized the given images and extracted HOG ...
1
vote
1answer
26 views

i need a characters /letters dataset for matlab

My final project is number plate recognition.i need a data set of A-Z characters and 0-9 letters. i donot find it on any website give me a data set or send me a link. i have to make a neural network ...
1
vote
1answer
126 views

What is difference between detrend and normalization? [closed]

matlab function detrend subtracts the mean from data. If data contains several data columns, detrend treats each data column separately. One of the normalization technique is subtracting the mean ...
0
votes
0answers
54 views

How to visualize SVM classifier output?

After applying SVM non-linear polynomial kernel, how to visualize the output of the classification performance in MATLAB? If anyone knows, please help.
0
votes
0answers
59 views

Searching for machine learning algorithm for probability prediction - Matlab

I have a problem, and I'm not sure if there's a suitable algorithm. Let's say I Have a matrix A mX3. The first two columns are coordinates, and the third is the density of flowers in the area in some ...
0
votes
1answer
174 views

Linear Regression of Sine wave using Gradient descent Not working [closed]

I am writing an algorithm to fit a sine wave. I want to have 4 parameters ( amplitude, frequency, phase & centre position). When I tried to program with all 4 parameters I wasn't able to find a ...
1
vote
0answers
159 views

How to identify ARIMA model parameters

I am trying to build ARIMA model, I have 144 terms in my standardized time series, which represent residuals form original time series. This residuals, on which I would like to build ARIMA model, are ...
1
vote
1answer
126 views

Classifying hand written digits dataset using Probabilistic neural network (PNN)?

I am trying to apply Probabilistic Neural Network (PNN) on MNIST dataset using MATLAB on 28000 samples. I tried to build the model but it gave an error saying matrix dimension exceeds memory showing ...
0
votes
0answers
179 views

LVQ (Learning vector quantization) not starting on MNIST dataset?

I loaded MNIST dataset into MATLAB,and started to apply Learning Vector Quantization using lvqnet(hiddenSize,lvqLR,lvqLF) <...
1
vote
0answers
30 views

How to create a neural network with many different values in Matlab? [closed]

I want to create a neural network in Matlab. I have 16 import matrices in each iteration, my import data changes in every iteration and there are more than 100000 iterations. The target is a matrix ...
0
votes
0answers
82 views

Optimization using Polak-Ribiere algorithm error

I am trying to write a code to minimize a function using Polak-Ribiere algorithm. The problem is that my descent direction (d) does not converge to 0 instead it keeps increasing which leads to my ...
-1
votes
1answer
141 views

accumarray function not working in matlab

I have an 2D array like the one shown below. 35046, 0.17 1963, 0.34 1135, 0.51 405, 0.68 99, 0.85 1, 0.85 15, 1.02 2, 1.02 ...
2
votes
1answer
211 views

Can we implement random forest using fitctree in matlab?

There is a function call TreeBagger that can implement random forest. However, if we use this function, we have no control on each individual tree. Can we use the MATLAB function fitctree, which build ...
0
votes
0answers
76 views

PCA or FDA on large data set

I want to reduce the dimensionality of my data but I'm having trouble calculating the covariance matrix needed for both principal component analysis and Fisher discriminant analysis. The dimensions of ...
2
votes
2answers
441 views

How to rank a feature importance?

If I trained a network using Neural Network classifier, how can I know which feature was most important for predicting the target variable? I mean how to create a "feature ranking" among the features (...
-2
votes
1answer
989 views

Python ,R or matlab for programming very large data set? [closed]

I have a very large panel data set (around 50m observations, size around 3G). Now I want to implement an algorithm on it. The algorithm is basically loops over observations. Ideally I want to use ...
0
votes
1answer
234 views

Why Matlab neural network classification returns decimal values on prediction dataset?

I have an input dataset (matrix 25x2275) which is normalized to values between 0 and 1. I also have a binary formatted output matrix (3x2275) like 0 0 0 0 0 0 0 0 1, 1 0 0 1 1 1 0 0 1 ... I imported ...
0
votes
1answer
2k views

How to calculate Precision and Recall using confusion matrix in Matlab?

I am working on 3 class problem.How to calculate precision,recall ,f-score,MCC of each class while using MATLAB. Here is my confusion matrix: ...
0
votes
2answers
104 views

How do I compare traditional classifiers performance with my proposed method?

I want to compare my proposed method with traditional machine learning classifiers like Multilayer Perceptron(MLP) and SVM to check the classification accuracy.How do I compare different classifiers?. ...
1
vote
0answers
231 views

Why is my classification tree is showing only one node, and how to resolve this issue?

I also asked here: https://stats.stackexchange.com/questions/287587/reason-of-getting-only-one-node-while-implementing-classification-tree-in-matlab Hello, I have $N=1520=19*80$ samples, each of ...
2
votes
1answer
163 views

Does CART algorithm takes into account in the order of the set of attributes?

when using matlab command 'fitctree' for classification purpose, and I change the order of the attributes I do not find the same Tree and thus the same classificaiton error? why? CART algorithm does ...
-1
votes
1answer
85 views

How to train Matlab on a range of IP addresses?

I'd like to train a Decision Tree using the Classification Learner App. I have a range of IP addresses, and a country that the IP address range belongs to. ...
0
votes
1answer
2k views

K-Fold Cross validation confusion?

I am using K-Fold cross validation to test my trained model.But i was amazed that for every K-fold the accuracy is different.For instance if use 5-K fold ,every fold has different accuracy.So which ...
4
votes
1answer
1k views

Using the cosine activation function seems to perform very badly

I have created a neural network to classify the MNIST handwritten numbers dataset. It is using softmax as the activation function for the output layer and various other functions for the hidden layer. ...
4
votes
1answer
263 views

Issue with backpropagation using a 2 layer network and softmax

I have a simple neural network with one hidden layer and softmax as the activation function for the output layer. The hidden layer uses various activation functions since I am testing and implementing ...