Bjorn Gustavsson

UIT, the Arctic University of Norway

Last seen: 2 days ago | Active since 2001

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Answered
How to fit ODE curve using loop?
Have a look at the answers to this question: ode-with-best-fit-adjustment-to-empirical-observations monod-kinetics-and-curve-f...

2 months ago | 0

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Fanbeam command projection directions and attributions clarification
The way I interpret the help and documentation the vertex with the source are located at negative y for rotation-angle zero. For...

2 months ago | 1

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Answered
Error in using ode45 for solution of nonlinear system of three equations which are interlinked to each other
Perhaps you need to check the size of each component in your ode-function: f = @(t,x) [-(p1 + x(2)) * x(1) + p1 * Gb + D; -p2 *...

2 months ago | 0

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Image processing and contour differentiation
This seems to be a problem where you could use the file exchange submission: distance2curve. Just brute-force loop over every po...

2 months ago | 0

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Excluding noise from a curve
Perhaps you will have to combine a number of criteria: 1, if you have a peak for x<300 2, and is above some threshold 3, and ...

2 months ago | 0

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Plot contour with "concave" XY coordinates
NOTE: edited so that the code runs here and displays the results CL The problem happens because griddata (and both scatteredInt...

2 months ago | 0

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How to loop through a specific file in various subfolders inside a main folder?
For this I (sometimes) do this type of thing: proj_root_dir = '/full/path/to/project'; data_dirs = {'damage1_case20','damage2_...

2 months ago | 1

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How to define for which plane lies a given point with coordinates?
This is easiest to do with a vector-algebra approach. Something like this: 1, the plane can be described as all points such th...

2 months ago | 0

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Answered
How to define legend (or assign arrows to each plot)?
Use the output from plot. Something like this: %Analytical solution of Duffing equation %% Matlab code to find the frequency r...

2 months ago | 0

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How to run multiple Matlab codes one after other even if one middle code will stop due to error?
You can try something like this: n_p = 5; run_status = zeros(n_p,1); try one run_status(1) = 1; catch run_status(1)...

2 months ago | 1

Answered
Solving differential equation using matlab
Do step-by-step and avoid using strings, like this: syms t real syms x(t) Dx = diff(x); D2x = diff(x,2); y = dsolve(D2x ...

2 months ago | 0

Answered
How can I find the angle between two vectors that answer should be between 0 to 2*pi
This question has been answered several times: angle-betwen-two-3d-vectors-in-the-range-0-360-degree, angle-between-two-vectors...

2 months ago | 0

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Answered
Contour plot: distorted contours and blank spaces in plots.
The reason you get these jagged contour-lines is that the triangulation-based interpolation you use is based on a Delaunay-trian...

2 months ago | 0

Answered
Non-pixelized image using imagesc (or alternatives)
That was not an immage you linked to but rather a movie (at a push a sequence of images). The first frame seemed reasonably simi...

2 months ago | 0

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changing ticks position on the graph
If you have coordinates for the edges of the cdata-elements then you can either adjust things manually to get what you want: dx...

2 months ago | 0

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mis match matrix dimension
As the commenters have indicated your request is to non-specific to have one solution, while we all expect you to have one speci...

2 months ago | 1

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Answered
Take the derivative of a SYMBOLIC Matrix with respect to a Vector
You might get close enough with jacobian to get the full output: syms x y real % simple 2 x 2 matrix: M = [sin(x+y) cos(x*y);...

3 months ago | 1

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Answered
Calculating the eigenvalues of simple shapes
If you have a binary image then why not just run through the svd and see what you get: I = zeros(256); I(64:(64+128),64:(64+12...

3 months ago | 0

Answered
Use of ODE45 for concentration plot help
To the best of my understanding you should include all three species in the ode-function. Perhaps something like this: function...

4 months ago | 0

Answered
How to describe loop for my ODE equations?
Write a function for these coupled ODEs. Inside that function you can use all the normal programmig tools and tricks you can thi...

4 months ago | 0

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Answered
Locking the Legend even if the object is deleted
If you explicitly set the axis of the plot, then you can hide objects outside the visible are and use their handles for the lege...

4 months ago | 0

Answered
Neural network for curve fitting (estimating function parameters)
In any type of parameter fitting problem you're facing the curse of dimensionality in one form or the other, because the number ...

4 months ago | 1

Answered
Image analysis for speckle pattern
A couple of things I'd try would be to determine the size-distribution of the speckles at different intensity-levels. This I'd d...

4 months ago | 0

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Multiple curve fitting via optimization
For this type of problem I would use lsqnonlin, so read the help and documentation of that function and what additinoally you ne...

4 months ago | 2

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Answered
Why cant I get a stable Cranck Nicolson discretization?
(caveat: I didn't run your code or analyze it, but speak from my experience with CN) Most likely you take too long steps in time...

4 months ago | 0

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Passing a matrix between several callbacks
If you have all your user interface in one figure (some calculator-like programme), then one way to store the matrix is in the '...

4 months ago | 0

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Joint Probability Density estimation function
Search the excellent File Exchange for everything you need but cannot find in your matlab-installation! Here's what comes up wh...

4 months ago | 0

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Integrating a line integral e^x(sinydx + cosydy) over an ellipse 4(x+1)^2 + 9(y-3)^2 = 36
For the integration you should use Green's theorem. It is beautiful, especially for this case. For the vector-field-plot you ca...

4 months ago | 2

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Answered
How to calculate a double integral inside the domain of intersection of two functions?
Perhaps you can use Green's theorem (you'd be very lucky if you could - but if you were to be that lucky in this case it would b...

5 months ago | 0

Answered
Create a function handle that is a sum of function handles
Your specification is a bit ambiguous to me, but if I interpret it such that you want to fit a function such that: (I've used...

5 months ago | 1