Community Profile # Jan

Last seen: Today 2009 以来アクティブ

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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How can I create a set of N diagnal matrices range from diag(1, 1, ... , 1) to diag(-1, -1, ... , -1) for testing purposes?
z = repmat(eye(4), 1, 1, 16); z(z==1) = 1 - rem(floor((0:15) ./ [1; 2; 4; 8]), 2) * 2; Generalized: n = 3; z ...

parfor slower than for
The main work in you example is the iterative growing of the array. This is a waste of time in sequential and parallel code. Pre...

To calculate the mean vector, covariance matrix, and correlation coefficient matrix of a RGB image. I have trouble getting the mean, cannot use the mean for matlab.
What do you expect this line to do: for i = l :length (img(:,:,1)) ? The length() command replies the longer dimension of the ...

large file slow running
I guess that the iterative growing of the array data slows down the processing. Remember that the growing of an array required ...

How to reduce data irregularly?

How to suppress anonymous function handle being created?
As usual the created variable is not shown, if you append a semicolon ; after the command. a = @(x) sin(x) % Output: b = @(y...

1日 前 | 1

Convert a jpg graph into matrix arrays
This is not possible. Saving the data with the low screen resolution to a jpeg removes the possibility to access the data in a h...

1日 前 | 0

removing some the elements in cell array
for k = 1:nunel(data_array) data_array{k} = data_array{k}(4:5); % or = data_array{k}(4:end); % Or: % da...

1日 前 | 1

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How do I pass a filename to a routine in Matlab's command window?
The error message is clear: The file does not exist. Although you assume, that the current folder is the same, this is not true....

1日 前 | 0

How to put uigetfile data from Pushbutton into Listbox?
I'm not sure what you want to achieve. With some guessing: function loadekstrak_Callback(hObject, eventdata, handles) % hObjec...

2日 前 | 0

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Performance difference between loop and recursion in fibonacci sequence
A cleaner version of your loop uses a pre-allocation of the output: function y = fibor_loop_2(n) y = zeros(1, n); % Pre-alloc...

2日 前 | 1

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Changing the range of for loop give different result
You cannot create a matrix, whose elements are matrices. This works with a cell array: A = cell(r+1, k+1); for i = 2:r+1 ...

3日 前 | 0

Matlab如何将cell中的矩阵进行合并？
R = {[3;2], [3;5], [4;2], [4;5], [5;2]}; nR = numel(R); f = true(1, nR); for iR = 1:nR if f(iR) ...

3日 前 | 0

separate strings that are inside a cell
Your description is not clear yet. I dare to guess: % Input (thanks Adam): C = {"sdfsd"; "dare"; ["abs";"ses"]; "erwe"; "serwe...

3日 前 | 0

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cd('E:/image_trans/Emis32_%d.bin'); This does not look like a valid folder name. Is there really a % character? Later on this i...

4日 前 | 0

Group values of a vector into new vectors according to magnitude
A = [17 323 100 3 278 220 45 351 212 51]; Y = discretize(A, [0, 50, 100, 360]) C = splitapply(@(x) {x}, A, Y)

4日 前 | 1

How to convert to a parallel program?
Pre-allocation is essential. Do not let array grow iteratively, but create them with the final size: n = 41; h = 1 / (n...

4日 前 | 0

How to select every 54th image in the folder?
A = 'D:\Your\A'; B = 'D:\Your\B'; AList = dir(fullfile(A, 'a*.jpg')); BList = dir(fullfile(B, 'b*.jpg')); nB = numel(BLis...

4日 前 | 1

Multiply cell by cell
Use a loop: for k = 1:numel(C_inside2) C_inside2{k} = C_inside2{k} .^ 2; end This is faster than cellfun: C_inside2 = ce...

4日 前 | 0

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How can I speed up (or avoid) a comparison in for loop?
What about omitting the loop: A(ismember(L, f)) = true; Or: LUT = [false, N < threshold]; A(LUT(L + 1)) = true;

4日 前 | 1

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This is not a trivial problem. In the general case it is a global optimization problem and there can be a huge number of equival...

4日 前 | 0

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Speed Up the for loop
Fmt1 = '%6.2f \t %6.4f \t %6.4f\t %6.2f \t %6.2f \t %6.2f \t %6.2f'; Fmt2 = '%s \t %6.2f \t %6.2f \t %6.2f \t %6.2f \t %6.4f \t...

4日 前 | 1

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Error while recording using audio recorder object
record_file=getaudiodata(recorder); ffname = sprintf('%s%s',record_file); getaudiodata replies a numerical array with the sign...

4日 前 | 0

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What should go in a next-generation MATLAB X?
A complete list of changes for each command. Currently we find "introduced in Rxy" already, but modifications of inputs and out...

5日 前 | 2

Avoid ode15s from freezing in parameter optimization
I've limite the time to [0, 15]. You see that one component explodes between t=15 and t=16. This let the step size of the integr...

6日 前 | 0

How increase calculate speed in for loop
Start with a simplification of the code: Depth = 5000; Num_Alines = 400; Num_Bscan = 300; Alines = 180 h ...

6日 前 | 0

How to add integers without correction?
a = int8(126); b = int8(2); tic for k = 1:1e4 c = bitadd1(a, b); end toc tic for k = 1:1e4 c = bitadd2(a, b);...

6日 前 | 1

Solving a System of ODEs using Euler's method
Your function to be integrated depends on t also. You call this x in the Euler method. At is easier to use vector equations: f...

7日 前 | 0

Matlab versions supported on Windows 11?
Windows 11 have not been officially released yet. We and MathWorks cannot know how the final version will work. There have been ...

7日 前 | 0

How to Copy Upper diagonal elements of matrix A into a new matrix.
A = [1 2 3 4; 2 1 3 4; 1 1 1 2; 1 0 0 1]; B = triu(A)

7日 前 | 0

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