# Questions tagged [matlab]

MATLAB is a high-level language and interactive programming environment developed by MathWorks. It is the foundation for a number of other tools, including Simulink and various toolboxes that extend the core capabilities.

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### Matlab code to show matrix in upper triangular form [closed]

I am creating a MATLAB function that would change the input matrix into a triangular form. The The code script is shown below. However, the code is neither efficient nor correct. ...
144 views

### Cross-Entropy Minimization - Extreme Code Performance

I'm working on a multivariate cross-entropy minimization model (for more details about it, see this paper, pp. 32-33). It's purpose is to adjust a prior multivariate distribution (in this case, a ...
21 views

### Implementation of calculation of gamma for RBF SVM

I have implemented the calculation of gamma value for RBF SVM as described in Liu et al (2012) [https://ieeexplore.ieee.org/abstract/document/6246300]. Here's a snapshot of the example from the paper: ...
46 views

### Custom Model intended to be used for Curve Fitting. Vectorization vs For Loop and jit numba capabilities

I am new to community and please pardon me if I didn't provide information as intended. This code is supposed to be creating a custom model which will be used with ...
75 views

### Optimizing nested loop for calculating geodesic distance

I segmented an image into N superpixels and constructed a graph based on that in which each superpixel is considered as a node. The information about neighbor superpixels is stored in ...
79 views

### Vectorizing equations for fsolve

I have a system of 49 equations and 49 unknowns ($x_{1},...,x_{49}$). All equations have the following form. \\$x_{s}\sum_{r=1}^{R}\sum_{t=1}^{T}a_{s,t}b_{rs,t}=\sum_{r=1}^{R}\sum_{t=1}^{T}a_{r,t}...
73 views

### My implementation of the Union-Find data structure in MATLAB

I was assigned the connected components labeling (CCL) algorithm and in order to implement the CCL algorithm I first had to implement the Union-Find algorithm. This is my try at it, any review and ...
54 views

### Reduction of time for the code of sorting RGB and Depth images according to timestamp values

I have RGB Images, Depth images and OpenPose Images(generated from RGB Images). The number of RGB and Depth images are different so I have to find the exactly which RGB images corresponds to which ...
32 views

### Calculating the term of dfdeta [closed]

I am trying to improve the time running of this code. Some dummies variable is defined and it is just some part of a lot of lines of code, but I tried it with dummies variables. It takes too much in ...
185 views

### My custom implementation of MATLAB's imdilate

I have been assigned to implement the morphological dilation operation without using MATLAB's imdilate, and I came up with the following solution: ...
71 views

### MATLAB / vs Python np.linalg.solve, heat diffusion, Why Python is slow? [closed]

I am solving a simple 1D steady heat question using spectral method. I am a long time MATLAB and Mathematica user and trying to learn Python. I compare only linear solving times and Python is way ...
48 views

### Kernel based conditional increments of many stochastic processes

I have written this function is part of a research project that involves analyzing time-series data from stochastic processes. We have a small number (from 1 to 3) of independent observations of a ...
21 views

### Simulation of splitting particles (MATLAB - Fortran) [closed]

I'm trying to write a code where a charged particle (charge=+20 called dimers), after a certain time, will split into a neutral particle and a smaller charged particle (charge=-10 called monomer). I ...
64 views

### Finding paths between triangles efficiently in 3D geometry #2

This post is an update of the one from here. I've updated the code and a couple pieces of the post itself. I've been writing some functions used to find paths between two types of triangles - alphas ...
116 views

### Finding paths between triangles efficiently in 3D geometry

An update to this post can be found here I've been writing some functions used to find paths between two types of triangles - alphas and betas. Alphas are triangles that have been in a zone we ...
743 views

### Getting saddle points of a matrix

My homework assignment: Write a function called saddle that finds saddle points in the input matrix M. For the purposes of this problem, a saddle point is defined as an element whose value is ...
80 views

### Simple SVM in MATLAB

I'm studying SVMs and wrote a demo in MATLAB (because I couldn't get a quadratic programming package to work correctly in Python). Right now it's simple and can only do linearly-separable cases (...
62 views

### Optimising multiplication of matrix rows with matrix slice/page

I've recently vectorized most of the code for an optimization problem but this one still eludes me. As the procedure and not the actual values are important here, I have replaced the original matrices ...
513 views

### Artificial Neural Network Classifier in Matlab

I am trying to build a neural network classifier. I have created a neural network with 1 hidden layer (25 neurons) and 1 output layer (1 neuron/binary classification). The dataset I am using has the ...
63 views

### Applying a function to columns of two matrices producing their combinations

I made a short snippet for applying a function f that takes two arguments (vectors) to columns of two matrices producing all possible combinations of those columns. ...
308 views

### Draw common tangents to two circles interactively in MATLAB

Requirement After a user draws two circles with their mouse successively, the program should draw all common tangents, if any, to them. Here is my implementation ...
63 views

### Vector operations

I want to perform the following procedure: I have two vectors x=[1,2,3] and y=[5,7,9] I want to take first element of ...
94 views

### Applying correction to a time series in Matlab

I face a computation efficiency problem. I have a time series of a non-monotonically drifting variable, that is measurements of objects going through a machine (where the measurement is made) in a ...
248 views

### Calculate Mersenne prime numbers in MATLAB

A Mersenne prime is equal to (2^n - 1), where n is an integer. 31 is a Mersenne prime since 31 = 2^5 -1. I need to write a code that calculates Mersenne primes between 1 and 10,000. Lastly I'm not ...
68 views

### How to pass pre-generated values to an anonymous function to speed up a fit?

In Matlab I am using the combination of fit and fittype function (from the curve fitting toolbox) to fit a signal using an ...
630 views

### Matlab IIR filter implementation

I need to implement the Matlab filter(b,a,x) function in Java. Before I do this, I would like to rewrite the function in Matlab before translating into Java. So far,...
72 views

### vectorize 2D gradient with spatially varying bins

The following code takes in some values ssh and solves the equations for the geostrophic motion (slide 8 here). The main part of the code is the computation of the ...
130 views

### Generating locations based on a power-law distribution of distance from their origin

I have a small function that gets a vector of N linear indices locations in a matrix and returns N new locations in the same matrix. For each of the input locations, a random angle tet and a distance ...
696 views

### Array splitting in sub-arrays of consecutive elements

I want to split an array in sub-arrays of consecutive elements. For example, for the array: a=[1 2 3 6 7 9 10 15] I want an output ...
3k views

### Matlab Code for Convolutional Neural Networks

I am using Matlab to train a convolutional neural network to do a two class image classification problem. I have an imbalanced data set (~1800 images minority class, ~5000 images majority class). As I ...
369 views

### Spectrum Analysis with Discrete Fourier Transform

Here is a simple implementation of the Discrete Fourier Transform: myFourierTransform.m ...
164 views

### Matlab and WidowX robot arm communication and control

For a class, we needed to control the WidowX arm from Trossen Robotics from Matlab and get as real-time of a feedback as possible. So I came up with a code for the Arbotix Robot-controller which is ...
73 views

### Extracting data from meshgrid output

I am trying to extract data from meshgrid output where zCs is 1000 x 1000 matrix of z values which is produced from meshgrid of s using bin2mat. s is a struct which has x, y, z data. res is 1000. ...
885 views

### Iterative Implementation of Towers of Hanoi

Here is an implementation of Towers of Hanoi based on few observed patterns1 from the easier recursive solution: ...
842 views

### Find first N primes

Here is code that returns the first N prime numbers: ...
129 views

### Exporting Matlab Figures as PDF with a Minimal Amount of Whitespace for use in LaTeX

About this code This Matlab function takes in the handle of a figure and exports a PDF containing a vector image of the plot. The caller of this function can opt to even remove the axes if he or ...
35 views

### Identifying local peaks among some 2D points

The following MATLAB code takes in multiple peak coordinates and heights and eliminates lesser peaks that are within a certain distance threshold of the highest peak of the vicinity. Is there a better ...
380 views

### Shortest distance from point to line segment in 3D

This function returns the shortest distance from a 3D point P to a line segment defined by two 3D points A and B. It projects P onto the line, then checks if this projected point lies between A and B. ...
236 views

### Optimizing MATLAB Loop

I have the following code in matlab and since the matrices are huge it takes more than one hour. I wanted to know where the bottle neck is and if there is any way to optimize this and make it faster. ...
223 views

### Removing undesired points from a mesh

I have a 3D data set made of a certain number of points (x,y,z) that cover a certain region of space. Using the scatteredInterpolant object I can interpolate this ...
1k views

### Convert Java data to Weka-friendly format without using ARFF

recently I've been working on machine learning with Java and Weka, and while I found the .ARFF format easy to understand (you just need an .ARFF file and Weka will do the rest :P), sometimes the ...
73 views

### AABB Intersections with Space Partitions, A Sample Code Performance and Reliability

I have originally written the following Matlab code to find intersection between a set of Axes Aligned Bounding Boxes (AABB) and space partitions (here 8 partitions). I believe it is readable by ...
58 views

### Selecting indices of a cell array that strcmpi-match the contents of another cell array

I have a Matlab structure with several fields, 3 of which are interesting here: ...
1k views

### Image Compression Using the Singular Value Decomposition (SVD) with MATLAB

I'm new to both linear algebra and MATLAB. I need help with this code with the objective of compressing image using the Singular Value Decomposition (SVD). The code is currently working, if I run with ...
217 views

### Possible “Angle of Incidence” of an RC tail-dragger plane

I am working for an Aero-Design team and we make RC planes that are capable of humanitarian aid. We wished to make a tail dragger and for stability reasons the "Angle of Incidence" (AOI) of the plane ...
518 views

### Implementation of Multiclass Perceptron

The following text is from Hal Daumé III's "A Course in Machine Learning" online text book (Page-41). I implemented the following: Is the implementation correct? ...
67 views

### Multi-layered Perceptron

Solution: Generate Training Set ...
99 views

### Neuroscientific testing

I have written the code below for the following experiment: Subjects get simultaneous stimulation of left and right thumb and have to tell which one was stimulated "stronger" (with higher intensity, ...