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# Romio

Last seen: 17 dagar ago Active since 2018

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ODE solver for restricted 3 body problem
I am trying to implement the following problem(restricted 3 body problem), but I don't know if my implementation is correct sinc...

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block diagonal matrix in the opposite diagonal
Is there any function/way to construct a matrix with block matrcies in the opposite diagonal. I know of blkdiag( ) but it gives ...

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ode15s solver produces wrong solution
I am trying to solve the heat equation such that using the method of line. I discritzed in space and used ode15s to integ...

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How to automate the matrix-vector multiplication using the index of a vector?
I have the following m = 50; a = 5 b = 2 c = 2 J = @(t,y) [diag(a*ones(1,m)) + diag(b*ones(1,m-1),1) + diag(c*ones(1,m-1),-...

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What can be done if fsolve cannot find solution?
Hello I have a large piece of code where I have a loop. In each iteration of the loop I use fsolve to find the solution of rela...

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Implementing implicit method for system of ODEs
I am trying to implement implicit Runge Kutta for solving a system of ODEs. Currently I was able to do it for scalar ODE (y'=-y)...

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How to create a loop on function handle
I want to write the following in an efficent way using a loop over j = 1:n. A is n by n matrix, t(i) is a scalar (where i is ano...

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How to create a matrix with special block diagonal structure
I would like to create a matrix that has the following structure ( The blue dots are ones and the rest is zeros) the number ...

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Change initial step length in fmincon
I am using fmincon to solve an optmization problem with the 'sqp' algorithm. I have set the variable 'StepTolerance' in options ...

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Structured trianglar finite element mesh
The available trianglar mesh in the PDE tool box here gives an unstructured trianglar mesh like this one How can get a stucture...

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optimizing two variables in fmincon with different sizes
I have a nonlinear optimization problem where I want to optimize an n x n matrix A and an n x 1 vector b. How can I set up the p...

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how to import a saved figure into a subplot
Hi If I am saving multiple figures as say f1.fig, f2.fig and so on with specific settings that are already saved. How can I imp...

mer än ett år ago | 1 answer | 0

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Question

How to connect multiple points in order using the shortest line
I have the following discrete points. The x and y coordinates are the following X = [-0.5305 -2.0960 -1.6192 -2.276...

mer än ett år ago | 2 answers | 0

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Weird java text in command window
Something weird happens to Matlab, I get this red text in the command window and it keeps changing whenver I move the mouse. Any...

nästan 2 år ago | 1 answer | 0

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Improving fit of custom function
Hello, I have the following curve. I want to fit it into a closed-form equation. I tried to use GRABIT to get a vector ...

mer än 2 år ago | 1 answer | 0

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adding the vectors at each cell in cell array
Hi I have a cell array where each cell contains a vector. I want to add up the vectors at each cell of each row. The cell arra...

mer än 2 år ago | 1 answer | 0

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How to extract one plot from multiple plots?
If I have subplot of 8 plots, How can I plot, say, the second plot on a seperate figure?

mer än 2 år ago | 1 answer | 0

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Error with installing MATLAB Support for MinGW-w64 C/C++ Compiler
Hi I am trying to run .c code on MATLAB. I did try using mex, but it gives me this error: Error using mex No supported compil...

mer än 2 år ago | 1 answer | 0

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Question

How estimate the frequency of one feature of an image
Hi Is there any way to estimate the spatial frequncy of one feature in an image? Meaning, if I have the follwing image, can I o...

mer än 2 år ago | 0 answers | 0

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Why fft results of discrete Fourier series coefficients are different from the actual definition
I tried to find the fourier coefficients of this discrete time singal x[n] = [1 1 0 0 0] using fft to get the coeffiecits. Howe...

mer än 2 år ago | 1 answer | 0

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equally spaced array of complex numbers
How to create an equally spaced vector from -2i to 2i with increment of 0.01?

nästan 3 år ago | 1 answer | 0

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data fitting that output eigenvalues and eigenvectors of the data
Hello, I have the follwing data points constituting three curves. Is there any MATLAB function that perform regressio...

nästan 3 år ago | 1 answer | 0

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How to solve difference equation with variable coefficients
I know if we have a difference equation in the form of a_1(y[n]) - a_2 (y[n-1]) = b_1(x[n]), where a's and b's are constants w...

nästan 3 år ago | 0 answers | 0

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Question

Error using plot: Value not a numeric scalar
I am using this running average function to smooth out dome noisey data. function y = RunningAvg(x,w) wts = ones(1, w) / w...

nästan 3 år ago | 1 answer | 0

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plot borders disappear when changing numbers to words in the axes
Hi I plotted some point data and changed the axis to words. But the right and up boarder of the plot disappeaed. Is there any w...

nästan 3 år ago | 0 answers | 0

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Edge distortion when resampling a signal
I have the follwing cosine signal that is sampled at rate fs = 32 Hz. f = 30; fs = 32; dt = 1/fs; t = -0.5:dt:0.5; c = cos(...

nästan 3 år ago | 1 answer | 0

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how to plot multiple decaying exponentials in one plot.
I would like to plot multiple decaying exponentials with different parameters (time, decay, peak). I was able to create this cod...

mer än 3 år ago | 1 answer | 0

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Question

how to plot decaying exponential
Hello, I'd like to plot a decaying exponential function similar to this plot, while being able to vary the spike time and rat...

mer än 3 år ago | 1 answer | 0

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Question

iterating over an ode solver
Hi there, I am writing a program to solve an ode system multiple times with different parameter values. I added the two param...

mer än 3 år ago | 0 answers | 0