Bjorn Gustavsson

Last seen: ein Tag ago

UIT, the Arctic University of Norway

1.086 total contributions since 2001

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Answered
Simulation of Shepp Logan phaton dataset
The phantom-function is a standard .m-function available in source-code, so you can read it clean and plain. It is simply a func...

etwa 22 Stunden ago | 2

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Different line types for multiple curves
Maybe you'll have to accept looping a little: lstl = {'-','--'}; for i1 = 1:4, set(p(i1),'linestyle',lstl{rem(i1,2)+1}) en...

4 Tage ago | 0

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Inputs must be floats, namely single or double.
When you integrate an ODE numerically there is no need whatsoever to introduce a declaration of T as a symbolic variable (the wa...

4 Tage ago | 1

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error occurring while solving odes using ode15s
Check your mass-matrix E and make sure it looks exactly like you expect. The 3 off-diagonal 1s looks peculiar to me. Then you ha...

5 Tage ago | 0

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Find Peaks error - Expected X to be strictly increasing
Check that your X-variable is actually monotonically increasing (you might have replicate points, which then messes everything u...

6 Tage ago | 0

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The legend does not show the right marker:
When using legend it is always preferable to use an array of handles returned from the plotting functions. Try something like: ...

7 Tage ago | 0

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stft for complex data
Shouldn't that be as simle as: Acmplx = I + 1i*Q; spec = fft(Acmplx); % or spectrogram etc HTH

7 Tage ago | 0

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How do I interpolate in 5d?
Have a look at the help and documentation for interpn. HTH

7 Tage ago | 0

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Sparse matrix from the columns of an initial matrix
Something like this might work: vals = []; idx1 = []; idx2 = []; for j = 1:n idx1 = [idx1,1:n]; c...

8 Tage ago | 0

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Is there a way to adaptively sample 2-D surfaces ?
It is not entirely clear what your "problem situation" or "design desires" are. These might be very important for what type of s...

8 Tage ago | 0

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Error using odearguments (line 21) When the first argument to ode23s is a function handle, the tspan argument must have at least two elements.
Your t variable will only have one component as you define it. My guess is that you want 100 elements between 0 and 1. If that's...

18 Tage ago | 0

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F(N) versus N plot for logistic differential equation
To solve for N you simply have to implement the ODE as a matlab-function, either as in an m-file or as an anonymous function-han...

18 Tage ago | 0

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How can i draw Confidence interval graph for my data?...(i'm beginner)
The second graph is certainly not correct - since it is centred around zero and not around the average at each point, you have t...

18 Tage ago | 0

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How can i make a colored 2d grid map, using a equation?
This is exactly what matlab is for, so you're thinking about the right tool. For a quick take-off I recommend you look through t...

18 Tage ago | 0

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How can I draw a kurdistan flag in matlab?
You can add something like this: phi360 = linspace(0,2*pi,43); r = 60 + 25*(-1).^(1:43); phi3...

19 Tage ago | 0

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how to solve error occuring in underlined part?
Run this code, but set the debug condition to stop at errors: dbstop if error Then you'll get a debug-propmt at the line where...

19 Tage ago | 1

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How can I do the image stitching with constant overlap area?
Something like this works for a smallish toy-example: % Read image Im = imread('cameraman.tif'); % Generate some tiles with a...

21 Tage ago | 0

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How do I convert fractional display to decimal display ?
You might have set format to rat somewhere, perhaps in a startup.m or the like. You could get back to more normal decimal output...

22 Tage ago | 0

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How to use interpolation instead of integrating in chunks with ODE45?
Too long code. But this is what I use for cases where I have to integrate ODEs with time-varying data for one parameter: functi...

22 Tage ago | 1

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Solving Complex Line Integrals
Wouldn't it be simplest to just multiply the radius of the polar representation of your unit-circle with the desired radius? g ...

22 Tage ago | 2

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Integration with piecewise function
Doesn't this work: C_v4 = @(T) 0.0516*T.^3.*double(T<=0.6) + .432*T.^6.7.*double(0.6<T).*double(T<1.1) + 0.468*T.^5.6.*double(1...

25 Tage ago | 0

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Solve a set of ODEs with given initial conditions and final conditions
To me this seems to be a problem that the shooting-method would be suited for. That will require you to solve the problem multip...

25 Tage ago | 1

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Matlab 2020a X11 forwarding crash
Perhaps the best solution is to run maltab in a VNC-vewer. That way you would avoid matlab having to rely on the X11 forwarding ...

26 Tage ago | 0

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Fitting nonlinear noisy data
When I do this I typically write my own error-function or residual-function and then use fminsearch (or some of the general opti...

26 Tage ago | 0

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Alternate form of eval function
You'll have to learn good programming-habits and utilise the vectorized capabilities of matlab. This looks like a case where you...

26 Tage ago | 0

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How to convert complex one sided spectrum into time domain
You can do something like this: function fft4real = symmetrize(fftOnesided) fft4real = [fftOnesided,0, fliplr(conj(fftOnesided...

26 Tage ago | 0

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add Int8 and int16
Think about what input variables you have, what type they have and which one you need to cast to another data-type.

26 Tage ago | 0

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how to add 2d plot in 3d?
I'd do something like this: clf surf(t,x,U+3,U),shading flat hold on pcolor(t,x,U),shading flat ax1 = gca; ax2 = axes('pos...

27 Tage ago | 0

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Transform 3D point cloud
If you have a 3-x-n array of point-coordinates you can rotate them in 2 ways, either rotate the points or the coordinate system....

27 Tage ago | 1

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How to apply the loop index on the output (filename) of the sprintf function?
In your "workspace" panel you see the values (sizes) of the variables as they are after completing the loop. Your filname-variab...

27 Tage ago | 0

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