MATLAB is a high-level language and interactive programming environment for numerical computation and visualization developed by MathWorks. MATLAB can be used when performing tasks such as signal processing and communications, image and video processing, computational finance, and computational ... ...

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21 views

Matlab Newton's Method Non-linear system

There is something wrong with this program and I cannot seem to find it. I am trying to calculate the solution of a non-linear system using Newton's method. Matlab keeps saying there is a problem with ...
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3answers
38 views

MATLAB: matrix multiplication with exponentiation

Normal matrix multiplication computes $C=A*B$, such that $C_{ij}=\sum_k{A_{ik}*B_{kj}}$ I want to compute D, such that $D_{ij}=\sum_k{e^{A_{ik}*B_{kj}}}$ Basically I want to exponentiate each ...
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2answers
6 views

Generating points from bi variate normal mixture densities

I am asked to generate 200 and 1000 points from a bi-variate normal mixture densities. I am trying to understand the algorithm, not just the matlab code (I have to write it, not use an existing ...
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1answer
21 views

plotting cone on matlab

Plot the portion of the cone $z=sqrt((x − 1)^2 + y^2)$ inside the cylinder $r = 2$ This is my matlab code. However, I get an error with the ezsurf line. Any ideas as to what I might be doing wrong? ...
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3answers
44 views

determine unit outward normal vector on a curve

It is necessary for me to find unit outward normal vector for the curve: $$\gamma=(x(t),y(t))$$ where $$x(t)=(0.6)\cos(t)-(0.3)\cos(3t)$$ and $$y(t)=(0.7)\sin(t)+(0.07)\sin(7t)+(0.1)\sin(3t)$$ I ...
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42 views

Dense packing of circles in unit circle, matlab code

I'm having real difficulties with a packing problem: Given M circles with equal radius r, determine the maximum radius such that all the circles can be fitted into the unit circle, without overlap. ...
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1answer
23 views

Incomplete Cholesky decomposition conjugate gradient method in Matlab

I have a problem in finding the numerical material that describing in detail for incomplete Cholesky combined with conjugate gradient method by using Matlab. Someone can help me? Many thank in ...
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1answer
26 views

Matlab solution for non-homogenous heat equation using finite differences

Given the following PDE (non-homogenous heat equation): $$ u_t(x,t) = c^2u_{xx}(x,t) + f(x,t) $$ $$ u(0,t) = u(l,t) = 0 $$ $$ u(x,0) = g(x) $$ $$ 0 < x < l ; t > 0 ; c > 0 $$ I wrote the ...
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1answer
24 views

Matlab Recursion Loop

I need to create a loop to answer part c of the following linear algebra question. I'm new to Matlab so this is extremely confusing. I'm not sure how to make a loop that "counts" from 0-25 in order to ...
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0answers
34 views

Searching solution for solving huge linear system in MATLAB or C

I am encountering a problem that my MATLAB code ran and an error occurs and shows that it is out of memory. My code is using finite element method to solve some complicated kind of integral equation ...
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1answer
25 views

Least Squares in Matlab

I'm stuck on part (d) I'm not sure how to code it so that it approximates that function in matlab. I'm also not sure if my (a) thru (c) are correct. But this is what I have so far. ...
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2answers
28 views

Matlab code for creating matrix

I have a problem, I am working with numerical approximations. Now i have $-1=x_0<x_1 <...<x_n=1$ with $x_i=x_{i-1}+h$ and $h=2/n$. Now given a function $f$ , I want to find $f(x_i)$ for ...
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1answer
28 views

creating a tridiagonal matrix in scilab/matlab

I want to create a tridiagonal matrix in scilab/matlab such that it uses for loops. I dont know how to create the matrix but here is what i have started ...
2
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0answers
39 views

Phase retrieval via SDP (semidefinite program) of 2D test image (Matrix completion)

In SDP based phase retrieval we have intensity measurement (abs(FFT2(x))^2) of the form A(xo) = |ak,x|^2 =b^2, phase retrieval is then find x that obeys A(xo)=b The quadratic measurements can be ...
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1answer
45 views

analytic/euler/runge kutta solutions comparison problem

i've been trying to solve 1st order differential equations with dsolve, euler andy runge kutta methods and compare them on graphics. for simplification, dy means dy/dx: first equation is y' = ...
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1answer
36 views

How to find the zeros of an integral?

I am having trouble finding the roots of an integral. For example $F(c)=\int_a^b{(x^2-c^2)}dx$ for some finite interval $[a,b]$. The problem is that I am trying to do this using numerical analysis. ...
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1answer
20 views

Matlab help to construct matrices with specified rank and such that each eigenvalue is real

I am reading this paper, where at page $68$, section 3.3 (numerical examples for the Drazin inverse), the randomly generated matrix with specified rank and with the property that each eigenvalue is ...
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1answer
31 views

Linear Algebra Matlab matrix loop?

I'm new to both linear algebra and Matlab, so naturally I'm probably asking an obvious question. If someone could attempt to explain to me in layman's terms how to go about answering this question in ...
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0answers
23 views

Discretization of a convolution integral for constrained optimization problem

I'm working on a constrained optimization problem in which an unknown forcing function, $u(\eta)$, is in the integrand of a convolution integral. To find an optimal shape for $u(\eta)$, the integral ...
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1answer
25 views

Hand calculation of magnitude of transfer function doesn't equal what MATLAB says…

I have a simple transfer function, given by: $$\frac{140,000}{s(s+100)}$$ I'm attempting to calculate the magnitude at $\omega$ = 100 rad/s. So I plug in, I get $\frac{140,000}{20,000}$ = 7 Then I ...
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1answer
21 views

Random sampling using Metropolis vs. Accept-Reject

I'm working on a project comparing the accept-reject (von Neumann) and Metropolis methods of sampling. I'm generating a sample of size $N$ from a normal distribution $N(1,(\frac{1}{2})^2)$. What I ...
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3answers
1k views

Matlab wrong cube root

How can I get MATLAB to calculate $(-1)^{1/3}$ as $-1$? Why is it giving me $0.5000 + 0.8660i$ as solution? I have same problem with $({-1\over0.1690})^{1/3}$ which should be negative.
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1answer
54 views

Incorrect indefinite integral on MATLAB?

any ideas why matlab is giving me an incorrect answer here? 1 set of commands syms x L N2 N2 = 6*x/L^2 - 2/L^2 N2 = (6*x)/L^2 - 2/L^2 expand(int(N2*N2)) ans = ...
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1answer
10 views

How to Estimate the mean and covariances for all classes from training set?

A training set of 2000 samples ( value :2000 * 2 ) named training_set. how can i estimate the mean and covariances for all classes from training set. already tried mean and cov function.but every time ...
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1answer
43 views

How to split a dataset in test and training set?

How can I split a data set in training and test data set after creating a data set named first_data (contains 3000 samples) in MATLAB? I want to split $2000$ samples as training and $1000$ ...
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0answers
11 views

Matlab symbolic toolbox with unknown windows size

I have a problem when using Matlab symbolic toolbox to do some automatic derivation. However, in my problem, a window size is defined but the size is unkonwn. I want to extract data in one window. ...
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1answer
40 views

Not able to use fzero function in Matlab

I am new to Matlab. I am trying to solve a non-linear equation using this inbuilt Matlab function called fzero() but it's not giving me the results. The main file ...
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0answers
28 views

Coupled Differential equation of second order in matlab

I have a problem solving a system of differential equations of second order in matlab: $$ \left\{ \begin{array}{l l}\frac{d^2y}{dt^2}= \frac{-y}{(x^2+y^2)^{3/2}}\\ \frac{d^2x}{dt^2}= ...
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0answers
27 views

finding angle of spirals along with length of it's line at a certain point

I'm tying to calculate the angles (the angle between each line segment and a horizontal ray to the right blue) of spirals at a certain point along with figuring out the length of the other lines. see ...
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1answer
29 views

Determining the value of ECDF at a point using Matlab

I have a data $X=[x_1,\dots,x_n].$ In Matlab, I know by using [f,x]=ecdf(X) plot(x,f) we will have the empirical distribution function based on $X$. Now, if ...
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1answer
29 views

Understanding the transformation of values when plotting logscale in Matlab.

I'm playing with some transistor test data and having trouble understanding what is probably a very basic principle. Below are my two graphs, plotted linearly and then with a logarithmic scale on the ...
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1answer
29 views

MATLAB Feedback

I am trying to use the feedback function in matlab and for the most part I understand it. But I came across this syntax: [x1 x2] = feedback(sys1, sys2, 1, 1, -1); ...
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1answer
29 views

How to convert rational numbers to irrational numbers in disp in Matlab

How can I convert rational numbers to irrational numbers in $\operatorname{disp}$ in Matlab? I wrote a method in Matlab to estimate the value using the Newton-Raphson Method but when I use ...
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1answer
36 views

Where is the fixed point? — Matlab is cluless too

Consider the differential equation $$\dot{k}(t)=f(k)-(r+t_1)k-f(1-k)+(r+t_2)(1-k)$$ where $k,t_1,t_1\in[0,1]$, $r\in\mathbb{R}$ and $f:[0,1]\to\mathbb{R}_+$. I'd like to solve for the fixed point ...
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1answer
42 views

MATLAB Eigenvalues

So I am trying to get matlab to output the correct eigenvalue/eigenvector of a matrix. The matrix is: \begin{array}{ccc} 0 & 1 \\ -3 & -4 \end{array} The eigenvalues are: $\lambda_1 = -1, ...
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0answers
53 views

Matlab project - Jacobi method for tridiagonal matrices…

I have to do a project in Matlab to my University and I don't quite understand what I should do. I was given script that solves systems of equations with Jacobi's method with given tolerance and ...
0
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1answer
22 views

Large error after factoring h from fourth-order Runge–Kutta method

Consider $$\frac{dy}{dx} = 2x-y, \qquad y(0)=1$$ That has an exact solution $y(t) = 2t+3 e^{-t}-2$. But I want a numerical solution. So I decided to use forth-order Runge–Kutta method ...
0
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1answer
30 views

Matlab calculate output

I'm trying to write a matlab function that takes in a transfer function and the input so it can calculate the output. So far, based on this information under I have the following piece of matlab ...
0
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1answer
36 views

Roots of an equation using Maple

I am using Maple to find the roots of a non-linear equation in one variable. When I solve the equation, I get only 2 negative roots whereas if I plot the graph of the function, it also shows that the ...
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1answer
104 views

Incorrect angle detected between two planes

I want to calculate the angle between 2 planes, Reference plane and Plane1. When I feed the X,Y,Z co-ordinates of pointCloud to the function plane_fit.m (by Kevin Mattheus Moerman), I get the output ...
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1answer
40 views

Beta-binomial random number generator

Could someone help me find a random number generator from a Beta-Binomial distribution in MATLAB, R or SAS? Thank you!
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1answer
26 views

Building an nth order ODE in Maple (or Matlab)

The question is simple: given a system of ODEs, how can one construct the equivalent nth order ODE in Maple? In my case I have $$ \begin{cases} y''(t)+x'(t)+x(t)=f(t)\\ y''(t)+z''(t)+z'(t)+z(t)=0\\ ...
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1answer
42 views

Inverse Power Iteration converges to largest eigenvalue instead of smallest?

I am trying to write a Matlab function that takes a matrix and an iteration count and performs inverse power iteration to output the smallest eigenvalue. The problem is, as k increases, the function ...
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1answer
73 views

create a Gaussian distribution with a customize covariance in Matlab

the Matlab function 'randn' randomize a Gaussian distribution with $\mu= \begin {pmatrix} 0\\0\end{pmatrix}$ and $cov= \begin {pmatrix} 1&0\\0&1\end{pmatrix}$ Ineed to randomize a Gaussian ...
2
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1answer
44 views

Higher order numerical PDE schemes near boundaries, implementation in MATLAB

Followup to my previous question. The first order scheme proved unstable for my pde: $$f_t + A y f_x - B x f_y =0$$ So I'm looking to implement a higher order scheme (using these tables). I was ...
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1answer
22 views

Fitting a polynomial model to the data

I want to fit a line to the following data. But the line I have obtained is far from the data. What is wrong in the following least square problem? ...
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0answers
61 views

calculate the second derivative using `ode45`

I have a second order differential equation. I am using ode45 to solve the problem. ode45 converts the equations to the first ...
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0answers
40 views

Low rank approximation using CVX toolbox in Matlab

I try to use CVX toolbox to do "low rank approximation" work. The code is as follows: ...
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1answer
73 views

Simulink model from a nonlinear State Space

I have the nonlinear state space already constructed in MuPAD as shown: u is the input and y is the output. What is the best way for me to take this to Simulink?
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1answer
54 views

How to draw or plot illustrative figures?

stackexchange users I would like to plot or draw some illustrative figures for my research paper. I've tried GeoGebra already. But couldn't draw them as I wanted. So my question is How can I draw ...