Community Profile # Bjorn Gustavsson

### UIT, the Arctic University of Norway

Last seen: 3 jours il y a Actif depuis 2001

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Question

matlabpath - order not respected?
In one of the toolboxes I have downloaded there are some functions (erf, gamma) that are shading the corresponding built-in func...

environ 2 mois il y a | 1 réponse | 1

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How to fit ODE curve using loop?

8 mois il y a | 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...

8 mois il y a | 1

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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 *...

8 mois il y a | 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...

8 mois il y a | 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 ...

8 mois il y a | 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...

8 mois il y a | 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_...

8 mois il y a | 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...

8 mois il y a | 0

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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...

8 mois il y a | 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)...

8 mois il y a | 1

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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 ...

8 mois il y a | 0

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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...

8 mois il y a | 0

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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...

8 mois il y a | 0

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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...

8 mois il y a | 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...

8 mois il y a | 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...

8 mois il y a | 1

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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);...

9 mois il y a | 1

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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...

9 mois il y a | 0

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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...

10 mois il y a | 0

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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...

10 mois il y a | 0

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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...

10 mois il y a | 0

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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 ...

10 mois il y a | 1

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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...

10 mois il y a | 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...

10 mois il y a | 2

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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...

10 mois il y a | 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 '...

10 mois il y a | 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...

10 mois il y a | 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...

10 mois il y a | 2

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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...

11 mois il y a | 0