Rik

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2,155 total contributions since 2017

E-mails with feedback/questions about FEX submissions are welcomed. In general I will post e-mails about Answers on the related page, unless there is good cause not to do so.

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Answered
Evaluate function over a mesh grid (without for loops)
You have to vectorize the function and split it into two steps: Jfun = @(x,y) (17*x.^2)/2 - 14*x.*y - 40*x + 19*y.^2 - 20*y; u...

3 hours ago | 0

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plot bar with two colors
If you insist on separate bar objects you can use the first part, if not, you can use the second part figure(2),clf(2)%ensure a...

14 hours ago | 0

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Processing txt multiple files in a folder and saving them using the original name but different format
Something like this should work: %replace this: filename = files(i).name; addpath('sorted_csv') dlmwrite(filenam...

15 hours ago | 0

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save an algorithm and call it
Store this in thomas.m function z=thomas(Ac,b,p_minus_2) %solving linear system with Thomas algorithm % % More explanation a...

1 day ago | 0

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Recursion function in matlab
function n=I_call_myself(n) disp(n) if n>0 n=I_call_myself(n-1); else disp('n has reached 0') end end

3 days ago | 0

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saving all data from for loop after image processing
You should use the '-append' option if you don't want to overwrite your text file every iteration.

3 days ago | 0

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Splitting an array up
You can modify the row indices you feed to mat2cell: data=rand(64,92690);%generate random data div=2048; c=div*ones(1,ceil(...

3 days ago | 1

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Ternary plot in MATLAB
The TrianglePlot function I posted on the FEX seems to work just fine (although I decreased the number of points for this exampl...

4 days ago | 0

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Plot data for unique temperatures imported from text file
%% code starts here r_data = importdata('reactions.txt'); %reaction_data = r_data.data; %fid=fopen('reactions.txt'); t = rea...

4 days ago | 2

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Answered
Pair of dice always rolled until all results happened between (2-12) ..Expected value of throws to find
Since this is homework I won't give a complete solution, but I will give hints. If you have trouble implementing these, feel fre...

4 days ago | 0

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How can i extract the value of an element of a sparse double?
You can convert the result to a full matrix. Indexing only extracts part of the array, but doesn't influence the sparse property...

5 days ago | 1

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How do you average each pixel in an image with a 9x9 square?
If you want the average (or something like a gaussian blur): use conv2, as described in the answer you linked. Read the document...

5 days ago | 0

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Running same program is giving different plot
Clear all should only exist exactly once in your entire code base. Replace it with clear or clearvars. If you want to have re...

5 days ago | 0

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Reshaping a Char Array
This should do it: A = ['12';'12';'12';'12';'12';'12';'12';'12';'34';'34';'34';'34';'34';'34';'34';'34';'56';'56';'56';'56';'56...

6 days ago | 1

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Answered
How to draw a inscribed circle having maximum radius inside the binary image. I have already identified the centroid of the object.
If you invert your image, you can use bwdist to find the point furthest from the edge. That distance is by default the radius of...

6 days ago | 0

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For Loop. My goal is for my code to recognize if the user inputs an empty 'grade' and then to loop back into itself until the user enters 10 grade values individually.
I would suggest using a cell array initially, which you can convert to a normal array after the loop. That way you can use the i...

7 days ago | 0

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How do I store values from a while loop and plot the values in fonction of the number of iteration?
Indices in Matlab need to be positive integers. You should create a separate time vector. And don't forget to index Temp, other...

7 days ago | 0

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Answered
minify Matlab code (minimize number of characters)
It took some time, but here is my solution. Strip all comments and line continuations. Separate the code and the embeded chars...

9 days ago | 0

Solved

Pizza!
Given a circular pizza with radius _z_ and thickness _a_, return the pizza's volume. [ _z_ is first input argument.] Non-scor...

9 days ago

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How can I create a Matrix according to a formula?
Learn about meshgrid and/or ndgrid. (assuming you mean D(i,j) instead of D(ij))

10 days ago | 0

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I need two outputs and I'm only getting one, please help me
You didn't actually assign any outputs, so Matlab only stores the first one in ans. If you want to actually store variables you ...

10 days ago | 0

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What is the probability that their children can travel in a straight line between any two points without leaving the boundary? In other words, what is the probability that the boundary is a convex quadrilateral?
If you want to do a Monte-Carlo-style simulation, I would suggest using rand to generate the coordinates. I would suggest puttin...

10 days ago | 0

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Annually averaging of a 4D matrix
You are using the color operator incorrectly. 1:2:3 doesn't mean [1 2 3], but [1 3]. If your syntax does indeed work for you, t...

10 days ago | 0

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finding a phrase in a modularized code with over 1000 functions
You can use Matlab tools, as Ameer describes, but you can also use external software. I personally find the performance of searc...

10 days ago | 0

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How to plot data with >2 dimensions?
Apart from plot3 (as Alan suggested), you may also consider using subplot to divide the different scenarios and using hold to pl...

10 days ago | 0

Question

minify Matlab code (minimize number of characters)
I would like to find a way that reduces the footprint of a function as much as possible. The actual functionality should not cha...

13 days ago | 2 answers | 2

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answers

Answered
How can I get my figure window to pop up with the animation playing when I execute the code?
You probably mean you want to make the figure the current figure and bring it to the foreground. If so: figure(1) cla;%i...

14 days ago | 0

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Answered
Find the element that is a sqrt of another element in the same array function?
To compare many elements to each other I would recommend the ismember function.

14 days ago | 0

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Refresh annotate on figure in loop
Create the annotation object once, and update the String property inside your loop. I would suggest drawnow to trigger the upda...

15 days ago | 0

Answered
Locate elements of a vector inside a meshgrid
I would suggest using ismembertol, or consider functions like normxcorr2 from the image processing toolbox.

16 days ago | 0