Answered
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...

12 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...

12 years ago | 3 answers | 1

3

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Answered
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; ...

12 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...

12 years ago | 0

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Answered
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...

12 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...

12 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...

12 years ago | 0

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Answered
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 ...

12 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...

12 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...

12 years ago | 0

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[DISCONTINUED] 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 ...

12 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.

12 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...

12 years ago | 0

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Answered
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...

12 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...

12 years ago | 1

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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...

12 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 =...

12 years ago | 2

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Answered
fft2: Frequency and wavenumber
Take a look at my post here for an idea of what is output from FFT2: <http://www.mathworks.com/matlabcentral/answers/24965-ff...

12 years ago | 0

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Answered
Gaussian FFT
Try plotting the absolute value of the frequency domain amplitudes... when your Gaussian is not centered at time 0, the phase ma...

12 years ago | 1

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Anyone using MATLAB on a LINUX OS??
Works fine for me on Redhat... running it on a 12-core, 96GB machine at work. Any simple-ish benchmarks you looking to test/meas...

12 years ago | 0

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I want to plot PSD for my input data(meters)
If you are measuring displacement in meters in the time domain, then your frequency domain amplitudes (after performing the FFT)...

12 years ago | 0

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Answered
Difference between fft and manually coding for a fourier transform
You are not correctly defining the frequencies "k" that are associated with the amplitudes in the frequency domain, but it start...

12 years ago | 0

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Answered
Scaling of fft output?
See my answer here: <http://www.mathworks.com/matlabcentral/answers/15770-scaling-the-fft-and-the-ifft> In order to conse...

12 years ago | 0

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Is there any alternative to if statements inside for loops?
Do you pre-allocated "Pin", if not... then before the for-loops put: Pin = zeros(8760,Ni); The inside of your for-loops ...

13 years ago | 0

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impulse response interpretation
I reran through the process of generating the Frequency Response data (G) using your code and the one from the FEX just to see i...

13 years ago | 0

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from time domain to frequency domain and back to time domain
Your "X" has shifted the zero frequency amplitude to the center. You need to use *ifftshift* to get it back where Matlab expects...

13 years ago | 0

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I cant generate a square wave in matlab using the square wave command
If you dont have the Signal Processing Toolbox, will the following work as an alternative: y = sign(sin(2*pi*100*t));

13 years ago | 2

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obtain the Impulse response from a frequency response
N = 1000; % Number of samples df = 20; % Frequency increment (in Hertz) Nyq = 10000; % Nyquist Frequency (in Hertz) ...

13 years ago | 4

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Answered
Can my integration code for an accelerometer data work for a Square wave?
Instead of trying to convert using your code, try mine located here: <http://www.mathworks.com/matlabcentral/answers/21700-fi...

13 years ago | 0

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Answered
Help With Plot Legend
If you are just trying to apply the 3 legend strings to 3 lines on a plot, then all you need to do is: legend(cell) Take...

13 years ago | 0