Questions tagged [matlab]
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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 ...
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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 ...
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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 ...
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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
...
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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
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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
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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
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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
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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 ...
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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
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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
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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 ...
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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 ...
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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
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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
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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
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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 ...
