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Bjorn Gustavsson


UIT, the Arctic University of Norway

Last seen: Today Active since 2001

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Answered
How to find index in multi-dimension matrix
You can do this in 2 simple steps: [xMax,idx1D] = max(X(:)); [i1,i2,i3,i4] = ind2sub(size(X),idx1D); HTH

4 days ago | 0

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Answered
Make an double integral function
By putting the product inside the first pair of square brackets you've made the formula look a little bit confusing - since the ...

5 days ago | 0

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Answered
adding random noise to an image for N times
The question is a bit too vague to be precisely answered. Image noise typically have some specific probability-distribution, pos...

8 days ago | 0

Answered
Picking data from graph?
If you have the signal S, the corresponding sample-times t and the start and stop-times t1 and t2 you can select the signal in t...

8 days ago | 0

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Answered
find onest and end of wave ?
You cannot in a strict sense. You will have to settle for the first and last wave-crest, or set some arbitrary threshold for the...

13 days ago | 0

Answered
How to segment image without losing information at the edges for finding centroid?
The only way I can imagine the meaning of centroid in a grayscale image like the one above is with the same definition as "centr...

14 days ago | 2

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Answered
How can I know more details about the function spap2?
Why don't you just try: edit spap2 From there you should be able to read for yourself. As far as I can see most functions are ...

14 days ago | 0

Answered
how to solve ODE that contains integration over time?
For this type of integro-differential equations the standard "first-stab" trick is to differentiate it one step, which should gi...

18 days ago | 0

Answered
Matlab mathematival modeling problem chemical eng
You have at least a couple of syntax errors in your code, namely the lines: 4*((dacetdt)^2)+10*dacetdt = racet; 4*((dAceticdt)...

18 days ago | 0

Answered
why there are two different comands for calculating convolution of two vectors?
The answer to: why returned: "To please all." That might be more of a matlab in-joke, but a true answer can only (possibly) b...

18 days ago | 0

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Answered
How to save/store/recuparate data from inside a nested loop.
This should be simple enough if you do something like this: Y_best = zeros(n_something,N_aoa); % Not clear to me what your Y co...

19 days ago | 0

Answered
Adding a legend to a Graph in Matlab
Would something like: legend([h(idx1(1)),h(idx1(2)),h(idx3(1))],... 'label1','label2','label3') work for this case. Here ...

20 days ago | 0

Answered
Does detrend function remove the mean of the signal?
If you read the help of detrend you will find: DETREND Remove a linear trend from a vector, usually for FFT processing. [...

22 days ago | 0

Answered
How to correct resonance phase plot
You could quick-fix this by plotting the phase-angle phi like: plot(unwrap(2*phi)/2) But you might have to check that you calc...

25 days ago | 0

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Answered
Tri-diagonal Matrix with varying diagonals
You have to set the elements of z to the values you want. In your version you set z to a new scalar (first time around the loop ...

26 days ago | 0

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Answered
Colormap on values related to bins
Perhaps you could use scatter to plot this. According to your description itseems as if you have a 2-D histogram type of data, b...

26 days ago | 0

Answered
How to include variable offsets in polynomial equations
Have a look at the help and documentation of taylor. That should help you a good part of the way - especially if you use the 'ex...

26 days ago | 0

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Answered
3 loops using sprintf to change directories doesn't quite work
Have a good look at the help and documentation of fullfile. That function is made to help you generate full filenames with absol...

26 days ago | 0

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Answered
I am not able to solve value of 3 constants with three equations
For given values of b, d, and L you have a standard system of linear equation. An obvious solution to these equations are all ci...

27 days ago | 0

Answered
reconstructed phantom image using sinogram as input??
Ok, you have quite a bit to fix here. 1, at least look at your intermediate results to at least check that your script does wh...

27 days ago | 0

Answered
How to use ode45 to solve coupled second order differential equations
It might be that your expectations on the modification of the beat in y, it might be something else. (When I converted the dsolv...

27 days ago | 0

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Answered
How to interpolate harmonic data series (without sin / cos equation defined)?
You should not "inpaint" data this way and then use that to extract SQ-curves or any such averaged quantities. You have the data...

28 days ago | 0

Answered
Solving coupled system of second order differential equations symbolically
Like the Greek godess used to say: Just do it!: y'' = k/m * y + w/m * z, z'' = J/I * z + w/I * y, syms t syms y(t) z(t) syms...

28 days ago | 0

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Answered
Convert netcdf time ('minutes since 2013-2-1 00:00:00') to actual date
Remember that datenum is in (fractional) days, while your netcdf-time is in minutes. It seems likely that you want to do: t1 = ...

28 days ago | 1

Answered
Solve systems of equations graphically
You can start investigating the surfaces of the functions f1(x,y) = x.^2+y.^2-29 and f2(x,y) = y.^2-4*x.^2-9 with something like...

29 days ago | 0

Answered
ODE45 outputs only zeros
When you have discontinuities in the ODEs (the derivative of command) then the safe approach is to separate the integration into...

29 days ago | 0

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Answered
Unable to perform assignment because the left and right sides have a different number of elements.
It appears because you try to squeeze in/stretch out an array with some number of elements into different number of elements of ...

29 days ago | 1

Answered
how to load mutiple mat files which has names in 'YYYYMMDD.mat' format?
You could do something like this, provided you have the filenames-of-interest: for iFiles = numel(dataFiles):-1:1 Sloaded{i1...

1 month ago | 0

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Answered
3 Differential equation using 4th order runge kutta
You have a function for a 2-D system of ODEs. That then is messed up: function diffeqs =ode_Q10(t,var) % t = var(1); % This ov...

1 month ago | 1

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Answered
Rotation Matrices - omega phi kappa vs yaw pitch roll
If you have mixed up the order of the rotations you might step through the different combinations of rotations and sign-conventi...

1 month ago | 0

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