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Stephan


801 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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Answered
Write to text file
Hi, note the permission argument for fopen. The way you call the files is read only permission. Best regards Stephan

5 days ago | 1

Answered
Hello, any one help me, what is this question's solution?
doc polyfit doc roots

5 days ago | 0

Answered
how can I solve this question? I need help
Have a read here: https://de.mathworks.com/help/matlab/ref/polyfit.html Best regards Stephan

6 days ago | 1

Answered
Error using fminunc function
Hi, you have a script that is named roots.m - roots is an inbuilt function. This causes problems. Rename your script to solve...

7 days ago | 1

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Answered
piloting log in y cordinate
Hi, try: format shortG kxx = 2.0e4; kyy = 8.8e4; kxy = 1.0e3; kyx = 1.5e3; cxx = 1.0 ; cyy = 1.0; cxy = 1.0e-1; cyx = 1....

10 days ago | 0

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Answered
How do I use ga correctly? fitness function
Hi, the line where ga is called [d endPop trace]=ga([],bounds(:,1),bounds(:,2),linOptFcn,IdentParams,[70 -1],'maxGenTerm',opt...

10 days ago | 0

Answered
help how can I use the PSO algorithme for the case of a matrix ?!
Hi, you can use the reshape function and take advantage of the linear indexing in Matlab. This will allow to work with matrices...

10 days ago | 0

Answered
Why the seond arugment in the command jacobian is not a vector of variables?
Hi, you declare b1...b3 as symbolic functions of t - not as symbolic variables. Thats why it doesnt work. Here is an example: ...

10 days ago | 0

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Answered
Vibration Analysis of a gas turbine
Hi, there are some example in the documentation regarding Vibration analysis: <https://de.mathworks.com/help/signal/exampl...

11 days ago | 0

Answered
How to find a polynomial of degree 2 that fits the given data with minimal approximation error? and then sketch discrete points and the graph of the polynomial
Hi, <https://de.mathworks.com/help/matlab/ref/polyfit.html polyfit> does the job: [p,S,mu] = polyfit(x,y,n) in your c...

12 days ago | 0

Answered
Failure in initial user-supplied objective function evaluation. FSOLVE cannot continue
Hi, this runs - not sure if it is really efficient, but it works: x0=[1,1,1,1,1]; fsolve(@F,x0) function m=F(x) syms y1 ...

12 days ago | 0

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Answered
help in solving an error
Hi, try: % Solving the 2-D Poisson equation by the Finite Difference ...Method % Numerical scheme used is a second order ce...

13 days ago | 0

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Answered
SOLVING LARGE SYSTEM OF EQUATIONS
Hi, try: a = sym('a',[1 15]); syms r p1 = poly2sym(a,r); diff = sym('diff'); eq = sym('eq'); fprintf('\n polynomial: %s\n...

14 days ago | 0

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Answered
where i can find video tutorials for GFDM for free?
You might be interested in this: <https://www.mathworks.com/videos/5gltewlan-waveform-generation-simulation-measurement-and-ov...

14 days ago | 0

Answered
Is there a way to combine number of matrices into one?
Hi, this solution is evil - since it uses eval: A = whos; A = {A.name}; B = string(ones(1,2*numel(A)-1)); B(2:2:end) = ","...

15 days ago | 0

Answered
Why is plot(x,y=0) not giving a line at y=0?
Hi, no need for this - since you are using R2018b you can take advantage of the yline function: x=0:0.01:10*pi; plot(x,2*sin(...

15 days ago | 2

Answered
How do i find the intersection between two curves?
Hi, usually this can be aproximated with quadratic functions - so you can use polyfit and polyval to calculate functionsthe de...

17 days ago | 1

Answered
How to plot the function y=sin(t)/t for -4*pi<x<4*pi?
Hi, at least two ways possible: Symbolic: syms t fplot(sin(t)/t,[-4*pi, 4*pi]) Numeric: t = linspace(-4*pi,4*pi); y = sin...

17 days ago | 0

Answered
Daily Return plot without interpolating lines
Hi, try: plot(returns) Best regards Stephan

17 days ago | 0

Answered
How can I store the value at each iteration of a genetic algorithm?
Hi, you coultd try this way: [x,fval,vals] = solve_problem function [x,fval,vals] = solve_problem ObjFcn = @myFitness; ...

17 days ago | 1

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Answered
How to solve an optimization problem with stability constraints using 'fmincon'?
Hi, i would try by writing a nonlinear constraint function for fmincon, that calculates the eigenvalues for each iteration an...

18 days ago | 0

Answered
Detect isolated nodes from tree graph mathematically through incidence matrix or adjacency matrix or any other mathematical method?
Hi, Matlab has his own graph functions. Learn how to define a graph object in Matlab, will help you saving a lot of time for ...

18 days ago | 0

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Answered
hi, how to import data from an Excel file
doc xlsread

18 days ago | 0

Answered
plotting a series of lines with specified colours
Hi, try: clf clc clear all close all % DATA Depth= [0 2 4 6 8 12 16 20 24 28 30 32 36 40]; % P-waves vp_upt= [3.27 5....

18 days ago | 0

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Answered
How to find the gradient of a function in spherical coordinates system ?
Hi, take advantage of the gradient function: syms x y z A = x^2*y+x*y*z res = gradient(A,[x y z]) results in: res = 2...

19 days ago | 1

Answered
the simscape of mass-spring-damping system can't get the ideal result
Hi, did you notice that you can accept and/or vote for useful answers? You have a asked a bunch of questions ang got some answe...

20 days ago | 0

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Answered
Reshaping 2x52 array into 1 special row
A = [1 2; 3 4; 5 6; 7 8] B = reshape(A',1,[]) gives: A = 1 2 3 4 5 6 7 8 B = ...

21 days ago | 1

Answered
How to get a function to accept a vector as input?
Hi, no if-else is needed, when using logical indexing: function [x] = classproj(W, k1, k2, d) x(W.*(1/k1)<d) = W(W.*(1/...

21 days ago | 2

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Answered
data from first line to two column
A=[1.4282E-01, 5.0537E+00, 1.2573E-01, 5.0537E+00, 1.8311E-02, 5.0513E+00]; B=reshape(A,2,[])'

21 days ago | 0

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Answered
difference between next two numbers
Hi, you may want to use the diff function. Best regards Stephan

21 days ago | 1

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