Community Profile # Bjorn Gustavsson

### UIT, the Arctic University of Norway

Last seen: 2日 前 2001 以来アクティブ

#### Statistics

All
• • • • • • • • • • • • バッジを表示

#### Content Feed

Find Centroid of area with 4 pouints
You could make good use of this little piece of information: Centroid of a finite set of points HTH

3日 前 | 0

Problem taking curl of a vector field.
If your sampling-points fall on a nice plaid regular grid then just use reshape to convert X, Y, U and V into 2-D matrices and e...

4日 前 | 0

Using symbolic math to retain accuracy. Arrays
Factor out the average of each row of C. That should give you one term of the row-averages of C and then the sum of the logs of ...

4日 前 | 0

How to find index in multi-dimension matrix
You can do this in 2 simple steps: [xMax,idx1D] = max(X(:)); [i1,i2,i3,i4] = ind2sub(size(X),idx1D); HTH

9日 前 | 0

| 採用済み

Make an double integral function
By putting the product inside the first pair of square brackets you've made the formula look a little bit confusing - since the ...

10日 前 | 0

| 採用済み

adding random noise to an image for N times
The question is a bit too vague to be precisely answered. Image noise typically have some specific probability-distribution, pos...

13日 前 | 0

Picking data from graph?
If you have the signal S, the corresponding sample-times t and the start and stop-times t1 and t2 you can select the signal in t...

13日 前 | 0

| 採用済み

find onest and end of wave ?
You cannot in a strict sense. You will have to settle for the first and last wave-crest, or set some arbitrary threshold for the...

18日 前 | 0

How to segment image without losing information at the edges for finding centroid?
The only way I can imagine the meaning of centroid in a grayscale image like the one above is with the same definition as "centr...

19日 前 | 2

| 採用済み

How can I know more details about the function spap2?
Why don't you just try: edit spap2 From there you should be able to read for yourself. As far as I can see most functions are ...

19日 前 | 0

how to solve ODE that contains integration over time?
For this type of integro-differential equations the standard "first-stab" trick is to differentiate it one step, which should gi...

23日 前 | 0

Matlab mathematival modeling problem chemical eng
You have at least a couple of syntax errors in your code, namely the lines: 4*((dacetdt)^2)+10*dacetdt = racet; 4*((dAceticdt)...

23日 前 | 0

why there are two different comands for calculating convolution of two vectors?
The answer to: why returned: "To please all." That might be more of a matlab in-joke, but a true answer can only (possibly) b...

23日 前 | 0

| 採用済み

How to save/store/recuparate data from inside a nested loop.
This should be simple enough if you do something like this: Y_best = zeros(n_something,N_aoa); % Not clear to me what your Y co...

24日 前 | 0

Adding a legend to a Graph in Matlab
Would something like: legend([h(idx1(1)),h(idx1(2)),h(idx3(1))],... 'label1','label2','label3') work for this case. Here ...

25日 前 | 0

Does detrend function remove the mean of the signal?
If you read the help of detrend you will find: DETREND Remove a linear trend from a vector, usually for FFT processing. [...

27日 前 | 0

How to correct resonance phase plot
You could quick-fix this by plotting the phase-angle phi like: plot(unwrap(2*phi)/2) But you might have to check that you calc...

| 採用済み

Tri-diagonal Matrix with varying diagonals
You have to set the elements of z to the values you want. In your version you set z to a new scalar (first time around the loop ...

| 採用済み

Colormap on values related to bins
Perhaps you could use scatter to plot this. According to your description itseems as if you have a 2-D histogram type of data, b...

How to include variable offsets in polynomial equations
Have a look at the help and documentation of taylor. That should help you a good part of the way - especially if you use the 'ex...

| 採用済み

3 loops using sprintf to change directories doesn't quite work
Have a good look at the help and documentation of fullfile. That function is made to help you generate full filenames with absol...

| 採用済み

I am not able to solve value of 3 constants with three equations
For given values of b, d, and L you have a standard system of linear equation. An obvious solution to these equations are all ci...

How to use ode45 to solve coupled second order differential equations
It might be that your expectations on the modification of the beat in y, it might be something else. (When I converted the dsolv...

| 採用済み

How to interpolate harmonic data series (without sin / cos equation defined)?
You should not "inpaint" data this way and then use that to extract SQ-curves or any such averaged quantities. You have the data...

Solving coupled system of second order differential equations symbolically
Like the Greek godess used to say: Just do it!: y'' = k/m * y + w/m * z, z'' = J/I * z + w/I * y, syms t syms y(t) z(t) syms...

| 採用済み

Convert netcdf time ('minutes since 2013-2-1 00:00:00') to actual date
Remember that datenum is in (fractional) days, while your netcdf-time is in minutes. It seems likely that you want to do: t1 = ...

Solve systems of equations graphically
You can start investigating the surfaces of the functions f1(x,y) = x.^2+y.^2-29 and f2(x,y) = y.^2-4*x.^2-9 with something like...

ODE45 outputs only zeros
When you have discontinuities in the ODEs (the derivative of command) then the safe approach is to separate the integration into...

| 採用済み

Unable to perform assignment because the left and right sides have a different number of elements.
It appears because you try to squeeze in/stretch out an array with some number of elements into different number of elements of ...

how to load mutiple mat files which has names in 'YYYYMMDD.mat' format?
You could do something like this, provided you have the filenames-of-interest: for iFiles = numel(dataFiles):-1:1 Sloaded{i1...

| 採用済み