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# Bjorn Gustavsson

### UIT, the Arctic University of Norway

Last seen: Today 2001 年からアクティブ

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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);...

6日 前 | 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...

14日 前 | 0

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...

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...

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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...

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 ...

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...

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...

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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...

2ヶ月 前 | 0

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 '...

2ヶ月 前 | 0

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...

2ヶ月 前 | 0

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...

2ヶ月 前 | 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...

2ヶ月 前 | 0

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...

2ヶ月 前 | 1

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...

2ヶ月 前 | 0

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...

2ヶ月 前 | 1

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...

3ヶ月 前 | 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...

3ヶ月 前 | 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...

3ヶ月 前 | 0

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...

3ヶ月 前 | 0

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...

3ヶ月 前 | 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

3ヶ月 前 | 0

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 =...

3ヶ月 前 | 0

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...

3ヶ月 前 | 1

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...

3ヶ月 前 | 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 ...

3ヶ月 前 | 0

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....

3ヶ月 前 | 0

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...

3ヶ月 前 | 2

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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...

3ヶ月 前 | 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 = [...

3ヶ月 前 | 0