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Stephan


806 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
how can i see the linear variation in the graph?
H = [ 1:2:11]; L = 0.0065; %K/m T0= 288.15; % till 11 km T = T0 - L.*H; %K plot(T,H,'-o')

ongeveer 9 uur ago | 0

Answered
Applying Boundary Condition to ODE45
Hi, you can reverse tspan. If you for example use: tspan = [20 0] then the integration will be backwards and your con...

ongeveer 10 uur ago | 0

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Answered
a and b constant
% Only needed if x,y are not column vectors x = reshape(x,[],1); y = reshape(y,[],1); % solve for a, b x = [x, ones(nume...

ongeveer 16 uur ago | 1

Answered
Help me understand the Classifier App
Hi, see example 1 from this webinar: <https://de.mathworks.com/videos/machine-learning-with-matlab-100694.html> Also no...

2 dagen ago | 0

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Answered
Remove repeated values in a CSV string
mystring = '1,1,1,25,33,33,5,5,3,2,1,1' iwant = join(unique(split(string(mystring),',')),',') results in a string: mystring ...

2 dagen ago | 1

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

8 dagen ago | 1

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

8 dagen 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

9 dagen 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...

10 dagen 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....

13 dagen 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...

13 dagen 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...

13 dagen 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: ...

13 dagen 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...

13 dagen 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...

14 dagen 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 ...

15 dagen 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...

15 dagen 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...

17 dagen 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...

17 dagen 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) = ","...

18 dagen 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(...

18 dagen 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...

19 dagen 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...

20 dagen ago | 0

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

20 dagen 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; ...

20 dagen 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...

20 dagen 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 ...

21 dagen ago | 0

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

21 dagen 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....

21 dagen 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...

22 dagen ago | 1

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