Question


MOD bug? Or something else?
Seems to be a bug in *MOD*. The values inside the range from 0 to 1 that should result in *MOD* of 0 (or 0 to machine precision...

9 years ago | 2 answers | 0

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looking for an efficient way to activate all fprintf in the function
Probably not what you are looking for, but a quick way may be to just do a search and replace all (i.e., search for: "fprintf" r...

9 years ago | 0

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How to manipulate Plot Legend to show markers and colours seperatly?
It can be done... you will have to do some finagling, but it can be done. Here is an example where we have 2 different datasets ...

9 years ago | 7

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How to check if a file of certain type exists in folder?
You could try doing something like: dir_struct = dir( fullfile(your_path,'*pdf') ); if numel(dir_struct) == 0 % then ...

9 years ago | 0

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Plotting lognormal data on this type of graph?
The key ended up being *norminv*. Here is an example output of the program I made (see below for *probit* function): >> pro...

9 years ago | 0

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Question


Plotting lognormal data on this type of graph?
I would like to plot data on a graph similar to that illustrated in the figure below (except it is upside-down from my conventio...

9 years ago | 2 answers | 0

2

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I have a rather large matrix. The data was sampled at 100 Hz. I want to the data to look like it was sampled at 5 Hz
Use *resample* - This is an example of why you may not want to take every Nth amplitude: <<https://lh5.googleusercontent.com/...

9 years ago | 0

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use FFT in matlab and get phase plot
Here are the frequencies associated with the output from FFT: Nt = % Number of time samples Fs = ...

9 years ago | 0

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Area of a Spectrum
The area under your curve should just be: N = numel(x); dt = 1/fs; df = fs/N; y = fft(x)*dt; area_y = sum(abs(y))*d...

9 years ago | 0

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Answered
How to get back complete signal after doing IFFT
Can you provide an example of how you are performing the fft? Something like: a = your_dataset_in_the_time_domain; size_a ...

9 years ago | 0

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How to run 3D FFT?
Have you checked out *fftn*?

9 years ago | 0

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ifft and fft problem
Did you mean to use "fs_s" instead of "f_s" here: h1_s_hat = abs(fs_s.*ifft(ifftshift(h1_s_FT))); I guess that's why you...

9 years ago | 0

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Answered
MATLAB Answers Wish-list #2 (and bug reports)
I kind of wish that when we scrolled through the answers to questions (especially when there are many "answers" like this one), ...

9 years ago | 0

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Is there a built-in function that determines whether X/Y coordinates give valid polygon?
My attempt: % Assume polygon is valid answer = 1; % Set tolerance tol = 0.001; % Random set...

9 years ago | 0

Question


Is there a built-in function that determines whether X/Y coordinates give valid polygon?
If I have a vector of X-coordinates and a vector of Y-coordinates, is there a function that determines whether a valid polygon i...

9 years ago | 3 answers | 1

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How do you centre your plot at '0' on the X-axis after performing a Fourier transform?
*fftshift* might be what you are looking for. Does this example help? dt = 0.1; % Fs = 1/dt; N = 16; t = (0:N-1)*dt; ...

9 years ago | 0

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how is a Shock response spectrum estimated
You might take a look at this FEX submission: <http://www.mathworks.com/matlabcentral/fileexchange/7398-shock-response-spectr...

9 years ago | 0

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2D spectral energy density using fft2 - energy in spatial domain unequal to that in wavenumber domain
*[EDIT 7/06]* M=8;N=16; N=8;M=16; dx=0.1;dy=0.2; f = randn(M,N); % Energy in time domain energy_f = sum(sum(f.^2...

9 years ago | 1

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Answered
How can I choose a subset of k points the farthest apart?
Added a few more tests (including your latest) and added your data (instead of just random dataset), which may be of interest. R...

9 years ago | 0

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Simple question for GUI
Also wanted to add a good resource for those who want to learn how to program a variety of things in Matlab GUIs: <http://www...

9 years ago | 0

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Bandpass Filter By Using Butter
Okan - Ambient noise is like random noise... the frequency domain response (if you were to plot the abs of the frequency domain ...

9 years ago | 0

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How can I choose a subset of k points the farthest apart?
Went with a "simple" way - tried to maximize the sum of the distances between each point in the sub-set of "n" below (similar to...

9 years ago | 0

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Legend Problem
Matlab is only doing what you tell it to. One of the places where you define your figure, you have your "hold on" just after you...

9 years ago | 0

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MATLAB Answers Wish-list #2 (and bug reports)
Has someone already addressed the change from having our most recent answers listed first to (now) where our oldest answers are ...

9 years ago | 1

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FFT
Your first amplitude represents 0 frequency. When your data has 0 mean, your first amplitude should also be 0.

9 years ago | 0

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derivative using FFT properties
Based on the website below: <http://www.cl.cam.ac.uk/teaching/2000/ContMaths/JGD-notes/node11.html> I believe you would do...

9 years ago | 0

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cycles/pixel to cycels/degree
See this link: <http://www.cogs.susx.ac.uk/courses/acv/matlab_demos/fft_image_demo.html> About half way down: F = fft...

9 years ago | 0

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FFT of an image
See my answer here for a coded up description of what the 2D Fourier transform does using a random 2D image as an example (shoul...

9 years ago | 0

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Answered
why real part of fft (exp(at)) is negative in some parts in contrary to analytical calculation of fft(exp(at))?
Try plotting the *abs* result from FFT. Basically, you will not get a purely real, all positive frequency spectrum unless your t...

9 years ago | 0

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Area of a triangle
How about *polyarea*? >> x = [0, 0, 4]; >> y = [0, 3, 0]; >> area1 = polyarea(x,y) area1 = 6 >> area2 =...

9 years ago | 2

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