# Bjorn Gustavsson

### UIT, the Arctic University of Norway

**Statistics**

RANK**61**

of 264.974

REPUTATION**2.542**

CONTRIBUTIONS

**4** Questions

**1.437** Answers

ANSWER ACCEPTANCE **
25.0%
**

VOTES RECEIVED**380**

RANK**7.272** of 18.104

REPUTATION**117**

AVERAGE RATING**3.40**

CONTRIBUTIONS**17** Files

DOWNLOADS **51**

ALL TIME DOWNLOADS**28146**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**0** Highlights

AVERAGE NO. OF LIKES

**Content Feed**

Unexpected behavior of FFT

In the field (IS-radar) I work we have typical carrier-frequencies of 224-1000 MHz and the modulation band-width is a couple of ...

4 giorni ago | 0

HELP need to run Chebyshev code!

Save your chebeval-function in a separate file chebeval.m. Then call that function from your script. For now you can put both sc...

4 giorni ago | 0

| accepted

SIR model with recovered individuals may lose their immunity and become reinfected with the disease. But came with a failure about integration tolerances

You have an error in the SIR-equations. They should look something like this: %% fc_ode_SIR function dq = fc_ode_SIR(~,q,p) % ...

6 giorni ago | 0

Skipping certain lines using fscanf

For this rather loose file-format specification that you've been given (meaning that in a couple of days, weeks or months it wil...

6 giorni ago | 0

PLOT surface using 3 vectors of same length (NEED HELP!!!)

You can use multiple indices in the variables you create. For example if you do things like this: b=0; for i = -200:1:200 ...

13 giorni ago | 0

Gradient Descent Implementation on a function, as opposed to an equation

You could do something like this: 1, rewrite the function to take an array as input-parameter instead of a number of scalar par...

18 giorni ago | 0

| accepted

Y-values for the histogram

Perhaps you look for histcounts? Seems like that is the function that returns what is plotted in histogram. HTH

19 giorni ago | 0

| accepted

How to fix "matrix dimensions must agree" error

Whe you run into problems like this you will have to learn to use the debug-capabilities of matla. Do this at the command-line: ...

20 giorni ago | 0

adding counts of ordered pairs

One way to go about this is to use sparse: A1 = [1 4 3; 3 5 1; 12 4 7; 13 5 2; 14 1 1]; A2 = [1 5 ...

20 giorni ago | 0

| accepted

How to use Eigenvector and Eigenvalues of a matrix to formulate Entropy equation?

First you should extract the eigenvalues from the diagonal matrix (mainly for convenience): vLambda = diag(Vect); Then you wan...

20 giorni ago | 0

| accepted

Simultaniously fitting 4 functions: two functions share all parameters, all four functions share one parameter

function errtot = four_errorfcns(pars1to5,Xall,Yall,sigmaYall) err1 = sum( ( f1(pars1to5(1:3),Xall(1,:))-Yall(1,:) ).^2/sigmaYa...

24 giorni ago | 0

How to create stacked quiver plots?

This sounds like a straight use of quiver3? Either h1=quiver3(slice2(:,1),... slice2(:,2),... slice2(:,...

24 giorni ago | 1

| accepted

Plot multiple x axes on the bottom of a graph

You should have some good use of a couple of such tools from the file exchange: dual_axes addaxis multiple-y-axes The last t...

24 giorni ago | 0

Integration of system of ODEs fails, unable to meet integration tolerances

After only quickly looking at your problem, it seems to me that you launch the body in a direction into Earth. The first 2 and l...

24 giorni ago | 1

| accepted

Unrealistic fitting confidence levels in noisy data

This is most likely due to the large number of data-points you have. Compare with the simpler case of the uncertainty of the ave...

24 giorni ago | 1

Using geointerp and los2

If you check the documentation (browse on from the help) you will see this: load topo Create a raster reference object assoc...

25 giorni ago | 0

M_map file with contourf

You might get away by modifying the colormap with the brighten function, perhaps something like: brighten(-0.5) This should ch...

26 giorni ago | 0

| accepted

How to integrate using trapz function

The variable in X1 seems awfully constant, at 0.0166. The first input to trapz should be the x-coordinate of the points at which...

26 giorni ago | 0

| accepted

How to convert gray image frame into video frames?

Have a look at the help and documentation for the VideoWriter and writeVideo functions. HTH

circa un mese ago | 0

how to attach a matrix generated in loop below a matrix with same row size generated in previous iteration?

The "natural" interpretation of below to me would be something like this: C = [A;B]; But that only works if the number of colu...

circa un mese ago | 0

How can i fit ODE parameters to given frequency and amplitude data pairs with "lsqcurvefit"?

There are two issues you will have to solve. The first is to convert your second order ODE to two coupled first-order ODEs. The ...

circa 2 mesi ago | 0

Surface plot of scatter data X,Y,Z where unknown data is noise

If you have a good handle on the noise-distribution you could do that. But for plotting purposes I would go for setting missing ...

circa 2 mesi ago | 1

Test if input number is divisible by 3.

Have a look at the help and documentation for while. Also from the question I guess that you're reasonably new to programming. I...

circa 2 mesi ago | 0

Fast fourier tranformer for Time series data

It seems that you're a bit too close to the Nyquist frequency. If you try: [NUM,TXT,RAW]=xlsread('data.xlsx'); dt = mean(diff(...

circa 2 mesi ago | 0

Anisotropic diffusion for a fingerprint image: resolution issues.

You might find that you have more control over the anisotropic diffusion with the cedif or eedif functions from the nonlinear-di...

circa 2 mesi ago | 1

Detect and remove outliers in signals

Be very cautious when changing bad-data-values to some default-value - that will eventually lead to (since we all know that the ...

circa 2 mesi ago | 0

Histogram or bar graph with greater than bin?

Maybe something like this would be good enough/a step on the way: a = 75*randn(2048,1).^2; h = histogram(min(a,260),0:10:260,'...

circa 2 mesi ago | 1

| accepted

Append to original file name and and save new file to directory?

You should be able to separate the path, name and ext of the full filename using fileparts. That should make it reasonably strai...

circa 2 mesi ago | 0

| accepted

Linear interpolation using inter1 function in matlab

First you should learn to read the help to the function you struggle with. Do that carefully and you will see that the typical u...

circa 2 mesi ago | 0

Is it possible to generate a sine wave like this? I tried combining 50hz, 100hz and 200hz together but I did not get something like this picture that I provided here.

Yes it is possible. You will have to make the phase-angle match at the frequency transitions (for simplicity make the time-windo...

circa 2 mesi ago | 1

| accepted