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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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14 views

Matlab code “glitch”? Matrix is turning into a single character, rather than staying a matrix [closed]

I am writing a matrix (a function) so I can plot it later on. It will go from theta2 = [-55:1:55] (-55 to 55) and the Y variable will be "theta4" which depends on theta2. The highlited area in the ...
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27 views

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 hidden neurons) and 1 output layer (1 neuron/binary classification). The dataset I am using ...
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1answer
44 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. ...
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1answer
126 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 ...
4
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1answer
44 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 x and then add each element from y to it, then I want to take second element ...
2
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1answer
86 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 ...
4
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1answer
135 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 ...
3
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1answer
48 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 ...
3
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1answer
171 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, writing out all the coefficients ...
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1answer
41 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 ...
4
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1answer
114 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 ...
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2answers
385 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 ...
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0answers
1k 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 ...
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2answers
140 views

Spectrum Analysis with Discrete Fourier Transform

Here is a simple implementation of the Discrete Fourier Transform: myFourierTransform.m ...
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0answers
115 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 ...
1
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1answer
62 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. ...
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2answers
616 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: ...
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1answer
303 views

Find first N primes

Here is code that returns the first N prime numbers: ...
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2answers
121 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 ...
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33 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 ...
4
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1answer
165 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. ...
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2answers
212 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. ...
4
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1answer
121 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 ...
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0answers
813 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 ...
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63 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 ...
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1answer
42 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: ...
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2answers
889 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 ...
11
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1answer
157 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 ...
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0answers
362 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? ...
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58 views

Multi-layered Perceptron

Solution: Generate Training Set ...
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0answers
98 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, ...
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0answers
91 views

Classifying test data into several classes

The following code is to classify the test data into several classes: ...
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1answer
2k views

Parzen window density estimation in MATLAB

This was my C# implementation of Parzen Window Density Estimation. The following is my implementation of the same in Matlab: parzen.m ...
5
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1answer
1k views

Function for plotting Julia Set

The Julia set is the set of complex numbers z that do not diverge under the following iteration: $$ z = z^2 + c $$ Where c is a constant complex number. Different values of z reach infinity at ...
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1answer
2k views

Plotting the Koch Snowflake

The Koch snowflake is a well known fractal. Beginning with an equilateral triangle, a smaller equilateral triangle is placed halfway along each edge of the shape. This process then repeats on each ...
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2answers
131 views

Locate a number in an array with a special ordering

Below are two examples of arrays (with a special ordering with odd numbers on one side, and even number on the other side) I have, with some given len: ...
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1answer
81 views

Counts instances for each category for many Matlab files

This is for machine learning. I have 5 matlab files: AWA, REM, S1, S2, SWS. Each one has 2 arrays: x and y. ...
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1answer
85 views

Wavelet decomposition of images

I am working on wavelet decomposition and found a formula for it and wrote it by myself for computation. The formula is: $$I_{LH}(i,j) = \sum_{p=1}^{N_L} \sum_{q=1}^{N_H}\ L(p)\ H(q)\ I(i+p, j+q)$$ ...
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2answers
1k views

Optimizing C++ equivalent of Matlab `filter` function

Minimum working example below. The Matlab filter function filters the input data x using a rational transfer function defined by the numerator and denominator ...
2
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1answer
78 views

Locate a number in an array with ascending even and descending odd entries

Below are two examples of arrays I have, with some given length: For some value z, I want to find the column the value is in. ...
3
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1answer
502 views

Exporting a table with header and subheader

I have an array matrix, for example A(3,3), I want to make a table with header names like, ['force','mass','acceleration'], the second row contains the units (subheader), ['N','Kg','m/s^2'], and the ...
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0answers
84 views

Making interpolations in a 4D matrix

I have Matlab code that is very inefficient and I need to run it several times. The code is basically a big parfor loop which I guess there is almost impossible to ...
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2answers
333 views

Running a simulation for all unique combinations of a range of parameters

I have written a script which is supposed to call the function at the bottom for each unique combination of values in the parameter vectors. That function is a simulation which I intend to run over ...
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1answer
131 views

Finding shortest distance between a point and a surface using Lagrange Multipliers

I am new to Matlab. Now I need to find the shortest distance between a given point to a surface, which is describe with a function. I am planing to implement the method described in the link below ...
4
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1answer
72 views

Vectorizing Two Sample Kolmogorov-Smirnov test

I'm implementing the Two-sample Kolmogorov-Smirnov test in MATLAB. I must admit I know very little of formal statistics and was simply trying to implement the description in wikipedia's page. Right ...
4
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1answer
868 views

Matlab implementation of Needleman-Wunsch algorithm

This code (an implementation of the path finding Needleman-Wunsch algorithm), given two sequences, correctly aligns and calculates the similarity of them. For example, given two sequences: AAA,CCC ...
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5answers
1k views

Benchmarks of various scientific programming languages for theoretical modelling

For a theoretical modelling course for biology students, I am trying to decide which would be the best technical programming language for doing evolutionary simulations in terms of elegance and ...
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1answer
124 views

Horizontally concatenating the entries of two matrices, and padding with NaNs

I have two matrices a and b that have, on each line, some values (null or not) and then a bunch of zeros at the end. I want to ...
5
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2answers
90 views

Extract the largest value for each day from a matrix

I have a matrix in which the right-most elements are repeated YYYYMMDD dates in descending order, for example: ...
2
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1answer
347 views

Verification of Sudoku boards

A valid Sudoku board has the following properties The board must be square (n-by-n). Let m = sqrt(n) All rows must contain the numbers 1-n All columns must ...