Jan

Last seen: Today

12,704 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
Array indices must be positive integers or logical values.
What is z1 and z2? Are these vectors? Then the message means, that z2((x(a)-x0)^2/z2^2+1) is not a valid expression, because ...

23 hours ago | 1

Answered
2D Interpolation with different sized matrices
A bold guess of what "corresponding x value when the y and z values are provided" means: x = [1 2 3 4 5]; y = [1 2 3 4 5]; z ...

24 hours ago | 0

Answered
How to append for each iteration?
hournum = 10; projectlength = 3; yield = cell(1, projectlength); % Pre-allocate as cell helper = zeros(1, hournum); % P...

24 hours ago | 0

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Answered
Functions in If Statements
This: for n = 1:FMn %cycle through files in the directory finalname = FMdir(n).name; end does the same as: finalname = ...

3 days ago | 0

Answered
How to code sparse diagonal matrix of increasing dimensions
Maybe this is not, what you want: for n = 500:50:1000 tic t1(n) = toc; end Setting t(500) in the 1st step ist not u...

3 days ago | 0

Answered
line and column of the minimun element of a matrix
m = [5 1 -400; ... -6 100 -6; 2 5 25]; [~, ind] = min(m(:)); [row, col] = ind2sub(size(m), ind) Or: [v, ind1]...

3 days ago | 1

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Answered
Problem with changing visibility of pop-up list
What is the purpose of: % Update handles structure guidata(hObject, handles); For some unknown reasons the value ...

3 days ago | 0

Answered
-If else- conditionals in matlab app.designer?
if strcmp(app.menu.Value, 'ac') && ... or define the values as string with double quotes, not as "cell string", which...

3 days ago | 0

Answered
Min and max value of many results
Use a vectorized method to obtain the results as a vector, not as a bunch of single variables: w = 0:0.001:1.393; k = 2; ...

6 days ago | 2

Answered
Unrolling a 20x20 grid of pixels into a 400 dimensional vector.
If the data are a collection of 500 matrices of the size 20x20: data = rand(5000, 20, 20) You can create the 2D matrix by: da...

7 days ago | 0

Answered
what is the probleme exactly u must be of size[3,20] but i find it [3,1]
Let me guess boldly: You want: A = [5/8, -1/4, 1/8; 1/4, 0, 1/4; 1/8, -1/4, 5/8]; b = [1;-1;1]; u = [5; 2; -4]; m = 20; u =...

7 days ago | 0

Answered
Vector ODE using forward Euler method
You have replaced the "x" of the formula by "y(1)", the "y" by "y(2)". Now you have to replace "u" by "y(3)" also and "v" by "y(...

9 days ago | 1

Answered
how to convert grey image to RGB
Your Pi is a [130 x 130 x 60] matrix, but your function gray2rgb() expects a 2D matrix as input. It is not clear how you want to...

10 days ago | 0

Answered
imread reads PNG files as empty arrays
When I run your code in Matlab 2018b I get a different result: img = imread('18_1b.png'); size(img) % 500 x 500 x 3, not...

10 days ago | 0

Answered
Increment components of vector till a desired limit
You know in advance how many iterations are needed: The smallest element must be increased until it is 100. A = [1 2 3 4 5...

10 days ago | 1

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Answered
Making sure the maximum calculated value in my function is represented in ode15s output.
ODE15S is designed to integrate smooth functions, as the other ODE integrators of MATLAB are. Running it with this not different...

10 days ago | 1

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Answered
Derivative without diff function
"Not enough input arguments. Error in @(x,t)x/t" You have defined fun to use 2 input arguments: fun = @(y,t) y/t; But in fun...

11 days ago | 0

Answered
Get all unique combinations from cell array for use as functional arguments
This can be achieved by 2 loops using linear indexing: for i1 = 1:numel(data) for i2 = 1:numel(data) immse(data{i...

11 days ago | 0

Answered
Combining cell arrays with empty doubles
Or simpler: a = {1, []}; b = {[], 2}; c = cat(2, a, b); c = c(~cellfun('isempty', c)); % Or: fullCell = @(x) x(~cellfu...

11 days ago | 0

Answered
Why I get this message?
Use the debugger to check the sizes of the arrays: dbstop if error Type this in the command line and run the code again. When ...

11 days ago | 0

Answered
Appending to a very large file
This line increases the problem: signal_mat = vertcat(signal_mat,temp_2); In e.g. the last step, you concatenate a 63 GB array...

12 days ago | 0

Answered
How would I convert a script to a function?
All you have to do to convert it to a function, is to add a head line: function array = randArrGen Maybe you want to define n ...

12 days ago | 0

Answered
check for keyboard press while using another application (such as Chrome)
The key should be caught, while the browser is the active window? This is a keyboard sniffer and running it might be conflict wi...

12 days ago | 0

Answered
Keeping the debugger out of the bowels of the machine...dbstop error question
This can be avoided by an exhaustive error checking, which catchs all not matching inputs as early as possible. Massive TRY-CATC...

12 days ago | 0

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Answered
How to return values of differential, not the function, from odefun, ode45?
You want the values of dy2dt? But you do have the equation for it already: dy2dt = (param.m2*y4^2*y1-param.k*y1+param.k*param.l...

12 days ago | 0

Answered
Append rows at the end of matrix for loop
A = rand(5, 2); B = rand(3, 2); Result = cell(1, 3); for k = 1:3 Result{k} = [A; B(k, :)]; end

12 days ago | 0

Answered
C++ Blur function to MATLAB code
You have redefined the function name "sum" as name of a variable. After sum=sum(A(:)) the symbol "sum" is a variable. The next t...

12 days ago | 0

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Answered
Two files with equal contents but with different SHA256 digest
The TIF files do not even have the same file sizes. How could you expect, that they are bit-wise identical then, which is requir...

16 days ago | 0

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Answered
Find maximum array values avoiding mat2cell.
For the expanded question in the comment to Bruno's solution you ask for the n largest elements: A = [NaN, NaN, NaN, NaN, 1, 6,...

20 days ago | 2

Answered
Creating dynamic variables using loops | Automatic Variables using loops
[EDITED]: The direction for shiftig needs a minus sign and is applied along dimension 1: Ha = [1 2 4 8 16; ... ...

20 days ago | 1

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