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Bjorn Gustavsson


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UIT, the Arctic University of Norway

1 100 total contributions since 2001

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Answered
If a structure exists in a file
You can explicitly check for the existense of a variable in a .mat-file: qwe = whos('-file','your-filename.mat','cDA_External_S...

ungefär 12 timmar ago | 0

Answered
help debugging 3-D plot code
You have to get your equations for x, y and z right: x = a*cos(phi).*sin(theta); y = b*sin(phi).*sin(theta); z = b*cos(theta)...

ungefär 12 timmar ago | 1

| accepted

Answered
Combined mean monthly values from 24 years of monthly data
Something like this perhaps: BV = table2array(baseline_values); clf subplot(2,1,1) imagesc(reshape(BV(:,4),12,[])') % Illust...

ungefär 22 timmar ago | 0

Answered
Plotting negative values on an histogram
It seems likely that you've mixed up BinCounts and BinEdges - it doesn't make much sense to have a negative number of something ...

ungefär 23 timmar ago | 0

Answered
M-point averaging filter to an image
Read the help and documentation for conv2. HTH

ungefär 23 timmar ago | 0

Answered
Why doesn't the ode15s solver work when I switch 'k1q','k2q','k12q' from a single value into vectors(more values)?
When k1q is an array you will get an error when you try to assign the product of that array with the scalar C(1) to dCdt(1) whic...

en dag ago | 1

| accepted

Answered
i am getting error in line 18 of invalid use of operator.please help me solving this
OK, so you want to solve 3 coupled equations of motion for some harmonically varying solution. First you have to understand the ...

3 dagar ago | 0

Answered
make a better map
You should try: shading flat instead of the interp option. You will have to accept the fact that you only have data in a 32-by...

3 dagar ago | 0

| accepted

Answered
Solving differential equations to get accurate plot as shown.
Since you get an oscillatory behaviour of (primarily) Cecm and Crec it is very likely that you have a bug for some of the reacti...

3 dagar ago | 0

Answered
How to use chebop function?
Have you installed the chebfun package? Have you added the chebfun install directory to the matlab-path? If you have it install...

4 dagar ago | 0

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Answered
Improving speed of readtable
It is a rather large data-file to read. You might reduce the read-time if you use load instead of readtable - that should reduce...

4 dagar ago | 0

Answered
How to create and plot an oloid in MATLAB
Have a look at the help and documentation of the convhull function. That should give you a solution for this task - in the sense...

4 dagar ago | 0

Answered
Multidimensional integration in matlab
Have a look at the help and documentation for integral2. That should be the function to do 2-D integrals, that sounds like the f...

5 dagar ago | 1

Answered
Why does version R2020b gives errors when running functions such as fmincon, when version R2019a runs properly.
Have you installed the optimization toolbox in your 2020b install? If not that is where that function resides. Check the existe...

5 dagar ago | 0

| accepted

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...

6 dagar ago | 2

Answered
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...

9 dagar ago | 0

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Answered
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...

9 dagar ago | 1

Answered
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...

10 dagar ago | 0

| accepted

Answered
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...

11 dagar ago | 0

Answered
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: ...

12 dagar ago | 0

| accepted

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

12 dagar ago | 0

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

13 dagar ago | 0

Answered
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...

13 dagar ago | 0

Answered
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...

13 dagar ago | 0

Answered
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...

23 dagar ago | 0

| accepted

Answered
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...

23 dagar ago | 0

Answered
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...

23 dagar ago | 0

Answered
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...

23 dagar ago | 0

Answered
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...

24 dagar ago | 0

Answered
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...

24 dagar ago | 1

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