Community Profile # Bjorn Gustavsson

### UIT, the Arctic University of Norway

Last seen: Today Actif depuis 2001

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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...

environ 19 heures il y a | 1

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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...

1 jour 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 '...

3 jours 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...

4 jours 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...

4 jours 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 jours il y a | 0

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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...

15 jours il y a | 1

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How can I find the filter bandwidth of Savitzky-Golay filtering?
QD suggestion: x = randn(4096,1); x_sgf = sgolayfilt(x,order,framelength); fx = fftshift(fft(x)); fxsgf = fftshift(fft(x_sgf...

15 jours il y a | 0

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Further processing of contour plot data
I would not do the average of the contours in a region, because if you have a rather flat region with a single spike in some reg...

16 jours il y a | 1

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Check summation from n=0 to 5 |n><n| in MATLAB?
If |n><n| is the same as <n||n> then you should have a look at the help and documentation to dot. That function will not general...

17 jours il y a | 0

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Decimal indexing for arrays in MATLAB
Have a look at the help and documentation for griddedInterpolant. That function might be what you're looking for. It creates a f...

18 jours il y a | 1

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How can I plot 18 lines in different colors on a single plot?
For that type of tasks I have had good use of the cmlines-function in the colormap-and-colorbar-utilities toolbox on the file ex...

18 jours il y a | 0

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How to adjust a curve fit such that it goes through a specific point
If this is a plot of an electron-density profile observed with an IS-radar, then your ionosonde fOF2 point is (expected to be) a...

18 jours il y a | 0

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i have a loop which runs from 1 to 7 producing four different figures per run. How do i automatically save each of these figures inside the loop. The loop is given below.
One thing I regularly do is something like this: fig_basename = 'My_current_fig'; for i1 = 1:7 %plot-and-decorate-code f...

19 jours il y a | 0

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How to rearrange random binary input for each iteration?
Have a look at the nextperm tool on the file exchange. It will allow you to cycle through all permutations. HTH

19 jours il y a | 0

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Combine different size matrix
If your D is a scalar that you want to expand into a diagonal matrix then perhaps you can do something along these lines: szA =...

19 jours il y a | 0

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How to detect wide ball in cricket using MATLAB. What should be the simple code for it.
One thing you can (should) try is to look at the differences between frames, that is subtract the previous frame from the curren...

24 jours il y a | 1

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How to extract data from specific row
You can do things like this in matlab: data_oi = data(data(:,1)==1|data(:,1)==2,:); This wouild give you your data of interest...

25 jours il y a | 0

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issue with colormap (colorcube)
Check that/if/how the two m-files differ. If they differ, copy the one you like better to the other system into a directory you ...

environ un mois il y a | 0

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Why am I obtaining incorrect values for Lipschitz 1/2 norms using the central difference method?
You've forgot to take the derivative of the function on-line, and you seem to take some kind of derivative on your own computer....

environ un mois il y a | 0

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How can write Dirac bra-ket notation in MATLAB? Example please.
That depends on what you want to apply the bra-ket on. If it is simple vectors you might get away with simple inner-products usi...

environ un mois il y a | 1

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strange error with varfun and anonymous function
These 2 modifications work: tbl = table(randn(5,1)); func = @(x) cumsum(x); varfun(func, tbl) % ans = % 5x1 table % F...

environ un mois il y a | 0

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How to solve system of ODEs with unknown initial value?
This works: % one second-order ODE rephrased as 2 coupled first-order syms q0 [2 1] syms a1 a2 syms q(t) [2 1]; A = [...

environ un mois il y a | 0

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Get grayscale like image from 2D representation of 3D random plot
Have a look at the help and documentation of histcounts2. That function will allow you to calculate this type of cumulative coun...

environ 2 mois il y a | 1

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Standard Deviation of an histogram
You don't want the standard deviation of the histogram. You want the standard deviation of the pixel intensities in the image. Y...

environ 2 mois il y a | 0

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Differential Equations with Inputs (Tank Draining Problem)
What you should do is to make a small modification of your ODE-function - such that it takes an additional input argument where ...

environ 2 mois il y a | 0

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Shift a square matrix along a bigger square matrix by one
Have a look at the help and documentation for the function circshift. That function should solve the problem you have described....

environ 2 mois il y a | 0

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Who owns the copyright of the code?
This will surely differ from country to country. Ask your trade union. In Sweden it is (at least used to be) so that if the com...

environ 2 mois il y a | 1

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How to access the double cell 5*1 ?
You could use cell2mat to convert the 5x1 cell-array with elements n_j x 3 into a matrix with n_many x 3 and then proceed as per...

environ 2 mois il y a | 0

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How to find the count of vertical lines in an image using Fourier Transform in MATLAB?
Why in the world do you want to use the Fourier transform to do that? You might be OK-ish for this specific pattern since it (su...

2 mois il y a | 1