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# Giorgos Papakonstantinou

### NTUA

Last seen: 1 month ago Active since 2012

I have only made this code longer because I have not had the time to make it shorter

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Determine transfer function from block diagram
I am having trouble to define in matlab the transfer function of the following block diagram. <</matlabcentral/answers/upload...

7 years ago | 1 answer | 0

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I don't get it... Help plotting this on MATLAB?
Annalise I will try to demonstrate how you may plot a piecewise function. In a similar manner you may plot yours. Lets assume...

8 years ago | 0

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Character input error message !!
If the |string| you get |from handles.m| is a _char_ class then |str2num| will produce an empty matrix. >> str2num('hello...

8 years ago | 0

how can i change cell array to matrix
You can do the following to find which values are >=-15 : dat= {'A' [12] [-20] [-75] [66] 'B' [9] [-10] [-50] [55] 'C' [15]...

8 years ago | 0

Ceate a vector of state space variable like A=[x(1), x(2), x(3),.....x(21)]
Hallo Ismaeel. There is no need to use loop to do that. Check the |<http://nl.mathworks.com/help/matlab/ref/colon.html colon>| u...

8 years ago | 0

Reverse order in column;flipud ain't giving me that.
Try to put outside the first loop: K = fliplr(I);

8 years ago | 1

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create a function that is the derivate of a f=@(t) function
Maybe this: fa = @(x)x^5-0.4475*x.^4-3.1*x.^3+3.085*x.^2-0.962*x+0.0943 g = sym(fa); dg = diff(g); df = matlabFu...

8 years ago | 0

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Conversion of a matrix into multiple column vectors
x1 = A(:,1).'; x2 = A(:,2).';

8 years ago | 2

Estimate length with out NaN's
If |x| is your vector. YourLength = length(x) - sum(isnan(x))

8 years ago | 1

Choosing specific area of points from xscale in plot
Hallo Tom. One way is to use brush/Select Data tool: <</matlabcentral/answers/uploaded_files/26924/Capture.png>> (ap...

8 years ago | 0

I would like to define a function that allows me to enter a symbolic expression in terms of x, raise that expression to the "n"th degree, then plot that expression from x=[-5,5]
Justin you have to define outside your function what is |x|. This is the reason why Matlab complains about |x|. It does not know...

8 years ago | 0

How to rotate xaxis labels (bar graph)

8 years ago | 0

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How can i read multiples files from a directory?
Assuming you want to open a few files. Create a cell|filenames|. Then the loop would be like this> filenames = {'file1....

8 years ago | 0

How to put script on pause instead of quitting when encountering error
Ekaterina, as far as I know you, could enclose the part of the code, which tries to establish a connection within a <http://nl.m...

8 years ago | 1

How to put radiobutton in GUI to cycle if?
If we assume the radiobutton handle variable name is |radio| then your |if| statement inside the |pushbutton1_Callback| should b...

8 years ago | 0

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Importing Data outputted by FreeFem++
u = [1 2 3 4 5; 6 7 8 9 10; 11 12 13 14 15]; reshape(permute(u,[2 1]), [], 1) or more compact: u ...

8 years ago | 0

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Does changing the axes turn tick marks off?
If you want to remove the ticks from both *x axis* and *y axis* , do this: set(gca,'Xtick',[], 'Ytick', [])

8 years ago | 0

Plotting (1-2*x)*log((1-x)/x)
The problem occurs inside the *log* parenthesis. The syntax that you have used tells Matlab to solve the equation: x = B/A ...

8 years ago | 1

Multiplying even and odd columns separately?
Here is one way: A =rand(100, 50); idx = mod(1:size(A,2), 2) ==1; % logical indexing of the odd numbers the...

8 years ago | 1

Creating a shape with varying arcs?
If I understood correctly you mean a spiral. Here's one way then: turns=5; theta = 0:pi/180:2*pi*turns; r = 2*o...

8 years ago | 0

Solving a formula in Matlab
x = input('Enter the value of x: '); % request user input y = input('Enter the value of y: '); S = input('Enter the ...

8 years ago | 0

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uiparent in Matlab 2013b
These are value/pair arguments. That means you have to write explicitly: hsp = uipanel('Parent', hp)

8 years ago | 0

How do I use the function "uicontrol" ?
The minimum example I can give you is: sld = uicontrol('Style', 'slider',... 'Min',1,'Max',50,'Value',41,... ...

8 years ago | 0

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how would i find a postive root
One way to find the roots is described <http://www.mathworks.com/matlabcentral/answers/103169-how-do-i-find-all-the-zeros-of-a-f...

8 years ago | 0

How to find the mean after every n columns?
NewMatrix = mymatrix(:,1:4:end); Youranswer = nanmean(NewMatrix , 2);

8 years ago | 0

Why is does the y axis of the graph have the same value all the way down?
Because |y(x)| barely changes in the interval |1*pi:0.1:pi|. Try a more densely spaced vector: i.e. x = -1*pi:pi/18...

8 years ago | 0

Newton Raphson m-file
I would recommend to take a look at Cleve Moler's book <http://nl.mathworks.com/moler/chapters.html Numerical Computing with M...

8 years ago | 0