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Jan


12,549 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
variable size matrix and converting letters to numbers
"user enter a variable size matrix": It depends on how you want to implement this: by a GUI, as Matlab code, as text file, in Ex...

9 hours ago | 0

Answered
Help on understanding the following matlab code ?
Step by step: flipud(xt): This flipps the order of elements vertically. Try it: x = rand(3,2) flipud(x) min(Y, [ ], 2) : fin...

9 hours ago | 0

Answered
Resuming from "keyboard" command?
Using debug commands for an interaction with the user is a really bad design. A dynamic modification of the workspace is very fr...

9 hours ago | 0

Answered
Memory usage very high
How do you observe the memory consumption? The Taskmanager displays the memory reserved for Matlab. If Matlab allocates memory a...

9 hours ago | 0

Answered
Return vectors from for loop as columns in matrix
Start with cleaning up the code. The lines Dplus; and Dminus; do nothing, so they are wasting time only and confuse the readers...

10 hours ago | 1

Answered
convert lower case to upper and upper to lower
You can use the function isstrprop with the category 'lower' and 'upper' to identify the specific characters. Then use the comma...

1 day ago | 0

Answered
Function run(scriptname) doesn't work.
Store the M-files in a folder, in which you have full access. C:\Users\ is a bad idea. Create a folder somewhere else, e.g. insi...

1 day ago | 0

Answered
Subtracting Vector from a Matrix
Matlab can subtract vectors from matrices automatically since R2016b - so called "auto expanding". Do you use an older version? ...

1 day ago | 0

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Answered
Include global variable declaration infunctions
Global variables are a shot in your knee in every case. Hiding them in scripts, which are called dynamically, impedes the debugg...

1 day ago | 0

Answered
deleted old version of Matlab (R2017b) keeps getting back
See https://nektony.com/how-to/uninstall-matlab-mac According to https://www.mathworks.com/help/install/ug/uninstall-mathworks-...

1 day ago | 1

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Answered
I found this bellow code in internet. While I run the code I noticed following errors.
This is a strange and inefficient code. Replace e.g. for i=1:len for j= 2:2 text_names(i,j)=txt(i,j); end ...

1 day ago | 0

Answered
Vectorise or Parallel Computing
This loop cannot be parallelized. If flux_edge is a vector and not a matrix, accumarray would solve the problem efficiently. Try...

1 day ago | 0

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Answered
How do I return an extra parameter using Matlab's ODE solvers?
If the problems mentioned in my comment are fixed, the solution is easy: Run the integration at first. Then provide the calcualt...

2 days ago | 0

Answered
Assign column index to output value
An easier way to create the submatrix: submatrix = M(i:end, :); The any() operates along the first non-singelton dimension. Fo...

2 days ago | 0

Answered
Index exceeds the number of array elements (4)
You stop Matlab at the error already by dbstop if error. Then use the debugger to check the sizes of the arrays: size(zplot) s...

2 days ago | 0

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Answered
Problem with Matrix indexing using vector
This is a job for sub2ind: a = blkdiag(ones(3),ones(3)); [r,c] = find(a); b = zeros(size(a)); index = su...

2 days ago | 0

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Answered
MEX passing Integer - wrong results
This sounds magic. Whenever magic things appear in discussions in the forum, or at programming in general, it is a secure signal...

9 days ago | 2

Answered
how to avoid for loop
A ,ore efficient version of the loop: nb = numel(b) - 1; counts = zeros(1, nb); % Pre-allocation!!! for i = 1:nb co...

15 days ago | 0

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Answered
Using matlab to find vectors that are orthogonal to another vector.
Do you mean 2D vectors? v = rand(1, 2) % Any test vector vp = [-v(2), v(1)] dot(v, vp) % Orthogonal means: dot pro...

15 days ago | 0

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Answered
11221 212211 212 12 1
Please post an exact copy of the error message in the forum. A rough paraphrasing will hide important details. Thanks. I assume...

15 days ago | 0

Answered
faster way to add many large matrix in matlab
The main time is spent in rand() in your example. With using ones() instead, the runtime goes from 0.71 sec to 0.25 sec on my ma...

18 days ago | 0

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Answered
Convert CurrentPoint to X and Y Value.
I guess that you do not want the coordinates relative to the figure, but relative to the data in an AXES object. Then: CP = get...

18 days ago | 3

Answered
P files cannot be analyzed to find their dependencies. Please add P file dependencies manually
I'd start with a web search: Ask your favorite search engine for "Matlab get dependencies of P file". You will find e.g.: https...

2 months ago | 2

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Answered
Is it possible to concatenate structures with the same fields in to one super structure?
Or with a loop: function S = CatStructFields(S, T, dim) fields = fieldnames(S); for k = 1:numel(fields) aField = field...

2 months ago | 3

Answered
Query in applying If command
if (abs(G(j)-O(:))<1) The if command needs a scalar condition. Therefore Matlab inserts an all() to evaluate the vector G(j)-O(...

2 months ago | 0

Answered
Index in position 1 exceeds array bounds (must not exceed 5).
The variable tab has the dimensions 5 x 10. You try to access the indices [100, 5, 10]. This cannot work. I guess, you want to r...

2 months ago | 0

Answered
How to Assign vectors to each dynamic variable name?
Don't do this. See: TUTORIAL: How and why to avoid Eval Hiding an index in the name of variables is a bad idea. Use arrays ins...

2 months ago | 3

Answered
Can I construct a matrix multiplying a scalar and a vector?
No, tis is not a standard multiplication. But you can create k based on i and j: i = 3; j = [4; 5]; % Solution 1: k(:, 2) ...

2 months ago | 1

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Answered
How can I maximize a function in Matlab?
Matlab contains some tools for minimization. A maximization does exactlly the same, if you change the sign of the optimization c...

2 months ago | 1

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Answered
How do I access a certain directory?
You can define the path of a file to access it: Folder = 'C:\Temp\'; FileList = dir(fullfile(Folder, '*.jpg')); for iFile = 1...

2 months ago | 2

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