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# Niels

### Universiteit Twente

350 total contributions since 2014

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How can i get one GUI to trigger another GUI?
What you could do is <http://nl.mathworks.com/help/matlab/ref/handle.addlistener.html add a listener> in GUI_2 to an object in G...

3 years ago | 0

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Question

All iterative solvers seem to fail for 3D poisson eqn
I have written a function that sets up a sparse matrix _*A*_ and RHS _*b*_ for the 3D Poisson equation in a relatively efficient...

3 years ago | 0 answers | 0

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Question

Optimization using lsqnonlin on very distinct data sets that depend on the same variables
I am working with some large data sets ( _N_ rows of data with 1 parameter varied, each consisting of _M_ points) for which it i...

3 years ago | 0 answers | 0

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Question

Diary does not print backspace ('\b') properly - alternative/solution?
I have a bunch of scripts + functions that output their progress to the command window. At the same time I would like to write t...

4 years ago | 3 answers | 0

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Sorting an array of strings based on number pattern
Ok, I should've searched better... Problem solved with a <http://www.mathworks.com/matlabcentral/fileexchange/47434-natural-o...

4 years ago | 0

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Question

Sorting an array of strings based on number pattern
I'm looking for an _efficient_ way to solve the following issue: Typically I read out all files in a directory that match a c...

4 years ago | 2 answers | 0

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Solved

2 b | ~ 2 b
Given a string input, output true if there are 2 b's in it, false if otherwise Examples: 'Macbeth' -> false 'Publius Cor...

4 years ago

Solved

Quadratic equations have the form: ax^2 + bx + c = 0. Example: x^2 + 3x + 2 = 0, where a = 1, b = 3, and c = 2. The equation has...

4 years ago

Solved

Find a Pythagorean triple
Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

4 years ago

Solved

Pattern matching
Given a matrix, m-by-n, find all the rows that have the same "increase, decrease, or stay same" pattern going across the columns...

4 years ago

Solved

Rotate counterclockwise a matrix 90 deg with left-bottom element
Example: Input [ 1 2 3 4 5 6 ] Output [ 3 6 2 5 1 4 ]

4 years ago

Output of changing number of columns
I believe a simple *repmat* should do the trick: fprintf(out, repmat('%14f ',[1,size(array,2)]), array);

4 years ago | 1

I'm using a for loop to create a new random variable X with range [0 1], I want the forloop to ignore values above 1 and iterate untill all the values are in range.
Change your *for*-loop to a *while*-loop if you want to keep looping. I also believe that you stored your data incorrectly, as ...

5 years ago | 0

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read a mat file once it appears in the folder?
One approach you could use is to write the filenames of all the current .mat files to e.g. a text document. You can import the c...

5 years ago | 1

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Help with 'Variable 'sa' is undefined on some execution paths'
You have 6 if-statements. Could it be that your x falls out of the ranges you've specified? Just for clarity - your total ran...

5 years ago | 0

Collecting a key press
It would be good if you provide us with a snippet of the code you are using right now. With the current information provided,...

5 years ago | 0

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How to calculate the area of the green shaded region in MATLAB
Is it not possible to simply calculate the difference between your y-values and the straight line, take the mean of every 2 neig...

5 years ago | 0

How to solve multiple equations dependent on each other?
Since you depend on your previous answers, you can simply loop through the equations and store the answers. x = ones(1,10);...

5 years ago | 0

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why doesn't the function sigshift work when i use it for x(n) = 2x(n - 5) - 3x (n + 4).
Your function *sigshift* seems not to be a built-in function. Are you sure the function/directory it is located in is included i...

5 years ago | 0

Is it possible to solve the equation in matlab without rearranging it??
Although I don't see why you would even bother to do it without rearranging, it is easily possible if you have the symbolic tool...

5 years ago | 0

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How to delete repeated column in this matrix?
b = unique(a,'rows','stable'); b = 6.7747 15.1502 126 ...

5 years ago | 2

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Find unique values in a sequence containing at least 3 elements
u = unique(x); a = histc(x,u); y = u(a>=3); This should do the trick. First determine the unique values in the vector...

5 years ago | 1

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How to convert from Roman numeral to decimal
The easiest solution is to get yourself a suitable tool from the File Exchange. For example <http://www.mathworks.com/matlabc...

5 years ago | 0

Index exceeds matrix dimensions, error problem
Your variable _look_ has a length of _eleimg_. You are trying to access some value between 1 and _Nx*Ny*L_ (which is equal to...

5 years ago | 0

How do I make a cell of cells in a for loop?
Your variable _omt1_ is put inside the wrong loop. Right now it is overwritten for every iteration of _k_. What you should d...

5 years ago | 1

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WHAT does this mean?
This probably means that you are referring to something like d(3,3) while the variable _d_ does not exist. You might ...

5 years ago | 2

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Find string (from table) in cell in matlab
If your cell array contains mixed datatypes, then _ismember_ indeed does not work. However, something like *find(strcmp('You...

5 years ago | 2

how do I select every single element of matrix except middle
If I understand you correctly, you could do something like this: A(A~=A(ceil(numel(A)/2))) or setdiff(A,A(ceil(nume...

5 years ago | 0

problem savind with diary function
If you add diary on after line 27, then it should work.

5 years ago | 0

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Question

Interpolate arbitrary curve to regular (x,y) grid
Hello, I ran into a problem that I cannot seem to solve in an elegant way. Say, I have a spiral-like curve which I want to...

5 years ago | 0 answers | 0