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Jan


Last seen: Today
12,938 total contributions since 2009

It is easier to solve a problem than to guess, what the problem is.

Questions about FileExchange submissions are welcome - get my address from the code. I do not answer mails concerning questions in the forum.

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Answered
How to create column vector by the transpose?
The quote ' is not the transpose operator, but the complex transposition. To be exact the tranpose operator is .' including t...

8 hours ago | 1

| accepted

Answered
How to bring Data in usable form?
To be able to guess, what "usable" means, we need to know, what do you want to use the data for. Maybe you should convert the ti...

8 hours ago | 1

Answered
When using ODE45, can I specify a variable to assume two different values during the timespan?
ODE45 is designe to integrate smooth functions only. To change a parameter you have to integrate in chunks: tSwitch1 = 10.0 tS...

8 hours ago | 0

Answered
Loop to iterate ode45 function
figure; axes('NextPlot', 'add'); for e = 0:0.2:1 [t, x] = ode45(@(t, y) F(t, y, e), [0, 20], [0, 1]); plot(t, x(:,1)...

9 hours ago | 0

| accepted

Answered
Find intersection between two curves
The intersection is the location, where both functions have the same value. Then their difference is 0. You can use fzero with ...

9 hours ago | 0

| accepted

Answered
How to downsample cell arrays based on specific criteria?
It would be much easier to reduce the number of points before you convert the nermical data to cell arrays. See my answer in th...

10 hours ago | 1

| accepted

Answered
Why is the upper axis grid not visible after exporting to .eps image
Did you enable the box? set(gca, 'Box', 'on')

10 hours ago | 0

Answered
Finding Maximum Iterations for False Position Method
The rule of thumb is to limit the runtime to a duration, the user can bear. So waiting for an hour to detect, that the algorithm...

10 hours ago | 0

Answered
How can compute sequential occurrence of elements in a vector
x = [ 0 0 0 0 1 1 1 1 1 0 0 0 2 2 2 2 0 0 0 0 0 3 3 3 3 3 3]; change = [true, diff(x) < 0, true]; index = diff(find(change))

10 hours ago | 1

| accepted

Answered
How can I transmit multiple variables to a function in the form of a single array?
You can use a struct: S.a = a; S.b = b; ... [output1,output2] = multi_input(S) function [output1,output2] = multi_input(S...

10 hours ago | 0

Answered
HOW CAN I SOLVE THIS?
What are the possible numbers in IEEE 754 floating point values between 1.0 and 2.0? x = 1.0 + k * 2^-52 with k = 0, 1, ... ...

22 hours ago | 0

Answered
Generate cell of random numbers with same size arrays
Creating a large array only to split it into parts needs more RAM than creating the random matrices in parts directly: C = cell...

1 day ago | 0

Answered
How can I record mouse clicks (left and right) with coordinates and time?
You can emulate this with WindowsAPI. Setting the window completely invisble does not work, because with Alpha=0.0 the mouse eve...

1 day ago | 0

Answered
Butterworth Bandpass Filter Design
See https://www.mathworks.com/matlabcentral/answers/273811-butterworth-filtering-with-bandpass-and-3-order

1 day ago | 0

Answered
num2str format
What does "I get a number from an API: 8.1784e+17" mean? Is this a char vector, string or a UINT64 or double scalar? In the last...

1 day ago | 0

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Answered
How can I get a loop to process all ".avi" files in a folder, then produce the corresponding ".txt" and ".png" file?
function FileExample() Folder = uigetdir('','Select Input-folder'); FileList = dir(fullfile(Folder, '**', '*.avi')); % Select...

1 day ago | 0

Answered
Array indices must be positive integers or logical values.
Nn = 1:2:30; Nn(i) = 60; Without a further definition, i is a constant with the value sqrt(-1). So which element to you wan...

2 days ago | 0

Answered
Multiply two terms at a set distance apart from each other in an array
The loop method: array = rand(1, 950); for i = 1:950 - 23 v = array(i+23) * array(i) end Stephen's vectorized approach ...

3 days ago | 0

Answered
How to deal with nested arrays where the columns and rows are in different dimensions?
I do not undestand why "Text Nr.1" appears multiple times. If this is a typo only: In = {your cell}; Out = cell(size(In)); f...

3 days ago | 1

| accepted

Answered
multiple default files for uigetfile
Under Windows this works: % Select multiple M-files: [File, Folder] = uigetfile('*.m', 'Choose files', '', 'Multiselect', 'on'...

3 days ago | 0

Question


PARFOR in real applications
I've installed the Parallel Computing Toolbox for some experiments with my code. To my surprise none of the codes run faster wit...

3 days ago | 0 answers | 0

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answers

Answered
How can I efficiently add multiple arrays generated in a loop?
EXP is very expensive. This is the bottleneck of your code. Instead of applying it to matrices produced by MESHGRID, provide th...

3 days ago | 0

Answered
Cumulative RMS in Matlab
Start with a mathematical definition of what you want to achieve. I guess you want this: x = rand(1, 100); % Your data % "Cu...

3 days ago | 0

Answered
Same result but without ode45
ODE45 is a stepsize controlled Dormand Prince Integrator with local extrapolation. If you want to get exactly the same results,...

3 days ago | 0

Answered
How to change a sequence of integers?
Rule 1 is easy: x = [2 1 3 4 1 1 3 1 2 1 2 2 5 3 2]; m = strfind(x == 1, [false, true, false]); y = x; xm = x(...

3 days ago | 0

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Answered
How can I speedup this for loop and ismember?
Without having working inputs, we cannot run the function. Then it is not possible to improve the code reliably. Except for one ...

3 days ago | 0

| accepted

Answered
How to take each 10 rows and put it in different group
X = rand(2000, 512); Y = reshape(X, 10, 200, 512); % perhaps: Y = reshape(X, 200, 10, 512)? % perhaps PERMUTE() such that the...

3 days ago | 0

Answered
how to creat a Vectorization instead of a Double Loop
The most important part is "myfcn", which is not shown yet. Can it be called with an array as input? What does it reply? Only 0...

3 days ago | 0

Answered
transfer variables between functions?
Variables cannot be "transfered" between functions. You need to provide them as inputs and outputs. Combining GUI and the actua...

4 days ago | 0

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Answered
Using Euler's method as ODE-solver in Matlab
How was the step size determined to be h=1/18? The author of the code wanted it to be 1/18. What does Euler's method in the w...

4 days ago | 0

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