Community Profile

photo

Stephan


863 total contributions since 2017

Knowledge means knowing where it is written...

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

Contact

Stephan's Badges

  • 12 Month Streak
  • Guiding Light
  • Introduction to MATLAB Master
  • Thankful Level 2
  • Knowledgeable Level 4
  • Revival Level 3
  • Speed Demon
  • Creator
  • First Answer
  • Commenter
  • Promoter
  • Solver

View details...

Contributions in
View by

Answered
Solving system of non-linear trigonometric symbolic equations
syms theta1 theta2 theta3 theta4 format long M_SUM = [(cos(theta1) + sin(theta1)/2)*(cos(theta1)/2 + sin(theta1)) + (cos(the...

4 hours ago | 2

Answered
Optimisation - fmincon error
Rename your script. NEVER name a script like an inbuilt function. This causes exactly the error you get.

9 hours ago | 1

| accepted

Answered
Difficulty implementing simulated annealing algorithm
rng default % For reproducibility x0 = [0.5 0.5]; % Starting point [x,y,flag,output] = simulannealbnd(@simple_objective,x0) ...

11 hours ago | 0

| accepted

Answered
I am trying to get non-negative values for the lsqlin function
https://de.mathworks.com/help/matlab/ref/lsqnonneg.html

12 hours ago | 0

Answered
creating a new column with three columns
Works also if the number of lines or columns is different to 25x3: a = [col1 col2 col3] b = reshape(a',[],1)

17 hours ago | 0

Answered
How can I use GA to specific variants with discrete variables?
Maybe you are interested in this question - and of course the answer: https://de.mathworks.com/matlabcentral/answers/401059-set...

18 hours ago | 0

Answered
what does mean: "@(x) ....."?
execute this code: x = 1:10 % create a vector with elements from 1...10 a = x(end) % access last element of vector...

19 hours ago | 1

Answered
linsolve time-consuming
Get rid of symbolic calculation - this makes code very slow and solve numeric: clear X Y % This works if your values are of si...

3 days ago | 2

Answered
Not able to solve an ode using dsolve
Consider: syms y(t) ode = diff(y,t) == -0.127.*(-3.*(log(7e-10.*exp(0.405.*y))).*(y - 0.01)); cond1 = y(0) == 0.01; co...

3 days ago | 0

| accepted

Answered
How to solve a system of third order non-linear differential equations
% create a 1.order system and a function handle syms u(t) w(t) r h nue eq(1) = diff(u,t,2) == -1/r*diff(u,t)+u/r-(1-nue)/2*r...

3 days ago | 0

Answered
logical expression in objective function
Hi, use the inequality constraints A and b as input arguments for the solver.

3 days ago | 1

Answered
Plotting a concatenated function (GUI)
https://de.mathworks.com/help/matlab/ref/str2func.html x=-5:.5:5 funy2=str2func('1.*x.^2+5*x+6') plot(x,funy2(x))

5 days ago | 1

| accepted

Answered
Why do I get 'Undefined function or variable'?
If u is calculated inside the function it should not be an input argument of the function. Also delete varargin - no need - resu...

7 days ago | 0

Answered
Fval Output by ga does not match output of fitness function evaluated at the respective x vector
you problably are are victim of rounding errors. try: FullDevice(x) to use the exact results of x as input for your Fitn...

12 days ago | 0

| accepted

Answered
Plotting the different solution via fzero solver against a range of one of the variable
N = 100; % define the parameters Nd = 1e23; e = 12*1e-12; %r = 0 R = 20*1e-9; Et_Ef = -0.21*1.6*1e-19; K = 1.3807e-...

19 days ago | 0

| accepted

Answered
Optimizing a matrix with cplexlp?
Hi, you could think about using graphs for this job: % your matrix A = [0 1 0 0 0 0 0 0 0 0; 1 0 1 0 0 0 0 0 0 0; 0...

20 days ago | 1

| accepted

Answered
lsqcurvefit cannot evaluate initial function, says insufficient input arguments
Have a read here: https://de.mathworks.com/matlabcentral/answers/465406-fmincon-error-not-enough-input-arguments it appears to...

21 days ago | 1

| accepted

Answered
Fmincon error not enough input arguments
Your objective function takes 2 input arguments - by default the optimization solvers only use 1 argument, which is the vector o...

22 days ago | 3

Answered
Why doesn't this code rotate and transform the spiral?
No for loop is needed: t = linspace( 0,4*pi,1000); r=@(t) sqrt(t); x = r(t).*cos(t); y = r(t).*sin(t); plot(x,y) %turns x...

22 days ago | 0

Answered
Solving two differential equations using ode45
This will help: https://de.mathworks.com/help/symbolic/odetovectorfield.html Follow the given examples and adapt them to your ...

22 days ago | 1

| accepted

Answered
can anyone help me ?
clear all; clc; close all; N=[100,200,300,400]; hold on for k=1:numel(N) %%les données mathématiques t = 0:1/(N(k)...

23 days ago | 0

Answered
Need to solve this
I assume you want real Solutions. Then try: syms a b c assume ([a b c], 'real') eq = [a+b == 204;... a+b*exp(-105*c) ==...

25 days ago | 1

Answered
How can I delete the elements of array on MATLAB?
To delete an array use: array1 = [];

26 days ago | 1

| accepted

Answered
ode23 and ode45 problem
% Solve symbolic (blue line in plot) syms y(x) x eqn = diff(y,x) == -2*x+4*y^2 sol_symbolic = dsolve(eqn,y(0)==0); fplot(sol...

1 month ago | 0

| accepted

Answered
substitute one cell of 3D matrix with another cell
A(:,:,158) = I; % where I is the 512x512 image you want to insert

1 month ago | 0

| accepted

Answered
How writing code sum 1+2+3+4+...+n
n = 4; A = sum(1:n)

1 month ago | 0

Answered
error variable y in fitness function
function y=fungsi3(x) y=2+exp(-(x(1).^2+x(2).^2)).*(sin(4*x(1))+cos(8*x(2))); end

1 month ago | 0

Answered
How can I expand x axis to have normal plot?
A(:,1)=data{:,1}; A(:,2)=data{:,2}; A=sortrows(A,1); plot(A(:,1),A(:,2))

1 month ago | 0

| accepted

Answered
Check to find if a row has an element occuring more than once
A = [0 0 1 1 0 0; 0 0 0 0 0 1; 1 1 0 0 0 1] res = (sum(A==1,2)>1) This works row-wise for more than 1 rows

1 month ago | 0

| accepted

Answered
how can I create a multiplication table and write it to spreadsheet in Matlab?
a = 1:5; t = a .* a' writematrix(t,'multiplication.xlsx')

1 month ago | 0

Load more