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Stephan

Last seen: Today
1.112 total contributions since 2017

Knowledge means knowing where it is written...

Interested in:
- Optimization
- Mathematical Modelling
- Improvement of my programming skills

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can anyone tell whre is the error ?
x=-2*pi:0.01:2*pi; y=exp(x); z=sqrt(exp(-x)); figure(3) p=plot(x,y,'r',x,z,'b'); p(1).LineWidth = 2; p(2).LineWidth ...

circa 2 ore ago | 0

How to replace the empty cells in a cell array by a 4-bits string?
load('Key.mat'); Key1 = Key(:); Key1 = reshape(replace(string(char(Key1{:}))," ","0000"),size(Key,1),size(Key,2)); results...

1 giorno ago | 0

How to generate a symmetric Toeplitz matrix?
>> toeplitz([-pi 0 pi]) ans = -3.1416 0 3.1416 0 -3.1416 0 3.1416 0 -3.14...

1 giorno ago | 2

"syms", "sym", and "mupad" functions cause MATLAB to freeze
R2017b had this bug, but it was fixed in update 7 and following. Try to install the latest update for your release - see Step 2:...

4 giorni ago | 0

How to use VPA (variable precision arithmetic) in calculating HH band via dwt on an image?
You can not do this. dwt2 accepts only double as input and outputs double. vpa works on symbolic variables and returns a symboli...

circa un mese ago | 0

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String to Categorical array
x = [zeros(1,120), ones(1,240)]; res = categorical(x, [0, 1], {'Z', 'O'});

circa un mese ago | 0

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Reducing 2nd order ODE into coupled ODE. Solve using Euler Method and graph.
tspan = [0 5]; % time span to integrate y0 = [3 0]; % initial conditions %Start of Euler Method syms y(t) E = diff(y,2) + ...

circa un mese ago | 0

How to convert cell array to double?
c = {[1 2],[2 3]} s = cell2mat(c) s = unique(s)

circa un mese ago | 0

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hi,i am getting error as not enough input arguments,while i run the below code....?? please let me know that?(the error is in second line of code)
Works fine for me, if called with *_2_* input arguments: res = trio(3,4) function x=trio(m,n) x=rand([3*m n]); ...

circa un mese ago | 0

How to solve coupled (differential) equations of motion using matlab?
Whta is the problem? There is an analytical solution (here assumed that vx0 and vz0 are equal to 1): syms w b g m x(t) y(t) z(t...

circa un mese ago | 0

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Undefined operator '/' for input arguments of type 'function_handle'
b=400; %mm d=500; %mm Asv = [3000 5000 3000 5000]; %mm^2 fckv = [30 30 90 90]; %Mpa num_fckv = numel(fckv); fsolve_opt...

circa un mese ago | 0

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Can't plot function
x = linspace(0,10); y = sqrt(1+x.^2)./sqrt(x.^4-x.^2+1); plot(x,y)

circa un mese ago | 1

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Fit Powerlaw to Data
https://de.mathworks.com/help/curvefit/custom-nonlinear-models.html

circa un mese ago | 0

Numerical Solution for a System of Three ODEs with Different Constant for Each Time Element
Use interp1 for this. Here is an example: https://de.mathworks.com/matlabcentral/answers/487412-using-ode45-to-solve-differenti...

circa 2 mesi ago | 0

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Text file manipulation, find specific lines, find there a string and replace the specific line with new content
There is a bunch of possibilities to manipulate strings: https://de.mathworks.com/help/matlab/ref/extractafter.html https://de...

circa 2 mesi ago | 0

Fitting an equation to a Sine Function with NonLinearModel.fit
"...I already tried using the "cftool" function in matlab but it did not have the equation I need...." Did you notice that yo...

circa 2 mesi ago | 0

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How to replace last 3 digits in a floating point number by another 3 digits
format long x = -3.141592653589793; a = 287; x_new = sprintf('%.15f',x); x_new(end-2:end) = (sprintf('%d',a)); x_new = st...

circa 2 mesi ago | 0

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I am trying to use ODE45, but I keep getting an error with myfcn saying I don't have enough inputs?
There are at least 4 problems in your code: 1. Split your main code and your ode function: tspan = [0 10]; f0 = [0 0]; ...

circa 2 mesi ago | 1

Having trouble with ODE45 and a System of Ordinary Differential Equations
For every equation you have to input an initial condition. You have 8 but only give 2 initial conditions to ode45. Also your ...

circa 2 mesi ago | 0

Is there a function to turn ?x2 matrix of coordinates of vertices of a polygon into a ?x4 matrix of coordinates of line segments of that polygon?
Yes, circshift will do the job: A = [2, 4; 5, 6; 6, 6; 8,5] B = [2, 4, 5, 6; 5, 6, 6, 6; 6, 6, 8, 5; 8, 5, 2, 4] % The sol...

circa 2 mesi ago | 0

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could anyone help me to display the values in the matrix which are greater than the average value for the following code
B, C and D are not needed, if you use the inbuilt function mean: A=[3.3734 5.1245 4.3729 2.8406 6.5283 4.8144 ...

circa 2 mesi ago | 0

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How can calcuate the lines of code efficiently?
Yes, you can if you avoid using a loop and vectorize your code - see here: tic %%%code nx=512; ny=nx; dx=1; dy=dx; format...

circa 2 mesi ago | 1

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how can i differentiate a constant in simulink?
You already have done everything exactly correct - Simulink also did what is correct. What is the derivative of y(t)=3 with resp...

circa 2 mesi ago | 0

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Eigenvalues and Eigenvectors of Symbolic Matrix
syms E t H = [E -t -t -t -t 0 0 0 0;-t E 0 0 0 -t -t 0 0;-t 0 E 0 0 0 0 -t -t;... -t 0 0 E 0 -t 0 -t 0; -t 0 0 0 E 0 -t 0...

circa 2 mesi ago | 0

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what is wrong with my script
clear all for loop_index = 1:2 x = input('Input number to convert'); units = input('Input the units to convert from','s...

circa 2 mesi ago | 1

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Any trick to name a variable with decimal number?
No, it is simply not allowed in Matlab. No way, no trick: https://de.mathworks.com/help/matlab/matlab_prog/variable-names.html#...

circa 2 mesi ago | 0

PULL OUT A SPECIFIC WORD FROM A LONG STRING
You might want to start reading here: https://de.mathworks.com/help/matlab/matlab_prog/searching-and-replacing.html

circa 2 mesi ago | 1

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How do I create a for loop to extract data from table?
No loop is needed: A = unstack(ReactionTime,'RESPONSE_TIME_ehmi','videostring') since you have invalid names for you video fil...

circa 2 mesi ago | 0

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complement of an image
I = fliplr(imread('cameraman.tif')); I1 = triu((I),1); I2 = tril(imcomplement(I)); I_res = fliplr(I1+I2); imshow(I_res) B...

circa 2 mesi ago | 1

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