Bjorn Gustavsson

Last seen: Today

UIT, the Arctic University of Norway

895 total contributions since 2001

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Answered
Multiplication of tranformation matrices gives strange result
You have confused permutation-matrices with mirroring and rotation-matrices. They are not the same. Your Rccw60 is not (what I t...

11 hours ago | 0

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How Do I plot Lat Long Altitude into a 2D countour
The problem you have is that you have coordinates for contours one level at a time, however since you have multiple closed loops...

1 day ago | 0

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Minimize Difference in Partition Sums from Experimental Data
Yup, you will find the algorithm and information here: partition problem (wikipedia). HTH

1 day ago | 0

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Newline in text files
When I want to explicitly write \n for new-line I include it explicitly in the string-specification: fid1 = fopen('Testfile.txt...

2 days ago | 0

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How to fix/steady the position of a counter in plot title.
Perhaps you can use the same type of zero-padding often used for filenames? Something like: tstr = sprintf('%04d',loop_idx); O...

2 days ago | 0

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Reshape data vector for a surf plot over a non-rectangular domain
If you have your x, y and z data in 1-D arrays you can use trisurf see the help and documentation for that function for usage. I...

2 days ago | 1

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2d image reconstruction from 1D images
That definitely looks like the text-book definition of the Radon-iRadon transform pair setup. The limitation here is the 10 stri...

3 days ago | 0

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Error: Index in position 1 exceeds array bounds
I think you would benefit from using the fact that there is information about the number of elements in a contour-segment in C. ...

3 days ago | 0

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Interp1-Input coordinates must be real.
Then it must be because your theta_n has become complex. How that came to be is impossible to guess based on this information. I...

3 days ago | 0

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correlation of two signal
Why do you want to use circshift? That would put some of your last samples first! That's not the way to go about this. To do th...

4 days ago | 0

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ODE solving lack of span inputs
OK, you have 2 coupled ODEs. If I expand the D/Dt(log(V(t))) to 1/V(t)*D/Dt(V(t) I'd get something like this: function dVdtdcad...

4 days ago | 0

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ODE solving lack of span inputs
The error is most likely in the second ode45-call. In that subfunction the time t will always be a scalar. You might want to cha...

4 days ago | 0

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Defining ODE function as function file
The way you've coded ConcA it should solve an ODE that looks like this: That might very well be the ODE you need to solve, bu...

4 days ago | 0

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How to use ODE solvers for a 2nd order differential equation with a Mass Matrix ?
As far as I understand all you have to is to do the same conversion from a system of second order ODEs to a twice as big system ...

4 days ago | 1

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Answered
Background Subtraction In Images:
Instead of using sprintf to generate the full (or relative, doesn't matter which) path to your images you should use fullfile. T...

4 days ago | 0

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How to remove Drift in the periodic signal after numerical Integration
The function detrend was made for this type of task. It should work like this: y_detrended = detrend(y); If you have a higher-...

8 days ago | 0

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ODE45 SIR model problem
In your initial conditions you have everyone perfectly "healthy" - therefore no one will ever get infected. You have to set at ...

8 days ago | 0

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list of csh commands to be run from matlab script
You might accidentally start a c-shell with your first csh command. My suggestion is that you put all csh-commands into a csh-sc...

8 days ago | 0

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haw i get two circles from arc noisy?
This is how I'd go about it: (Perhaps 0, apply some low-pass filtering to reduce the speckle and make image smoother.) 1, find...

10 days ago | 0

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Surface plot not displaying full data range
Once uppon a time... ...I was very annoyed with this behaviour of matlab's surf and pcolor functions - it treats the values and...

10 days ago | 0

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I want to use a 4th dimension as color in quiver 3d plot.
You will find at least a couple of color-capable quiver-like submissions on the file exchange. For example: quiver3_c or quiver2...

10 days ago | 1

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Answered
The function without if statement
That should to be the same as: VectorIm = ManyVecImage(:,Values < 10000); HTH

10 days ago | 0

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Calculating surface integral on Cartesian grid
For the sake of simplicity I'd just calculate the area of the grid-cells, multiply the velocity-vectors with those areas and add...

12 days ago | 0

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Numerically calculate the eigenstates and eigenvalues of a shrodinger equation with linear potential
If you go to the file exchange you will find a fair number of contributions that solves Schrödinger equations in different geome...

15 days ago | 1

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Solving a system of integral equations self-consistently
Why doesn't your solution to two (I assume similar) integral equations work for this case? Here's a QD-cookup (that doesn't wor...

15 days ago | 2

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Erasing the boarders in an Image
Simply crop out the black frame. Something like this: Img_frameless = Img_in(y_min:y_max,x_min:x_max); % for a grayscale image ...

15 days ago | 0

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Remove specific frequencies from FFT signal and reconstruct the signal after filtering those frequencies
Those high amplitudes are a noise in the signal. Not the noise in the signal. To remove such interference-components you will be...

15 days ago | 0

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Fitting Data to Circle (Data is only a small cutout of a circle)
For this case I think you'll have to put in some work. The radius of your circle is clearly very large if we're to judge from th...

17 days ago | 0

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Answered
How to round a value to the nearest value in an array?
At the file exchange I quickly found a couple of contributions that allows rounding to some desired precision. For this case cou...

17 days ago | 0

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Flip and rotate matrix
In my experience, it is best to test whether the flipping and rotation operations commute with a small enough example - do it wi...

17 days ago | 0