Stephan
Last seen: Today
1.465 total contributions since 2017Knowledge means knowing where it is written...
Interested in:
- Optimization
- Mathematical Modelling
- Improvement of my programming skills
Stephan's Badges
Contribute at least one answer each month for 36 consecutive months
Awarded to Stephan on 02 Apr 2021
Accept 5 answers given by other contributors
Awarded to Stephan on 11 Oct 2018
Obtain 50 solvers for a problem you have created
Awarded to Stephan on 11 Dec 2020
Solve all the problems in Introduction to MATLAB problem group
Awarded to Stephan on 28 Jan 2019
Be the first to solve a problem
Awarded to Stephan on 24 Apr 2018
Your submissions were downloaded 10 or more times in a month
Awarded to Stephan on 01 Nov 2019
Publish your first comment or rating
Awarded to Stephan on 09 Oct 2019
Publish your first submission
Awarded to Stephan on 09 Oct 2019
100 of your answers have been accepted
Awarded to Stephan on 04 Sep 2018
Answer 10 questions that were unanswered for more than 30 days
Awarded to Stephan on 22 Jun 2018
Create a problem
Awarded to Stephan on 24 Apr 2018
Provide your first answer ever to someone else's question
Awarded to Stephan on 26 Dec 2017
Comment on a problem or solution
Awarded to Stephan on 08 Jun 2017
Like a problem or solution
Awarded to Stephan on 08 Jun 2017
Solve equation (unrecognized function or variable)
% define t as symbolic syms t N = 5.62; R = 6.40; W = 600; eqn = (10 + 2.*W.^(2).*t.^(2) - 8.*W.^(4).*t.^(4))./(10 +23.*...
alrededor de 4 horas ago | 0
How to doI plot F(x) = [1 -(10/x)]/[1-(100/x^2)] for X ranging from 100 to 1100 at an interval of 50?
F = @(x) (1-(10./x))./(1-(100./x.^2)); x_vals = 100:50:1100; plot (x_vals, F(x_vals))
alrededor de 10 horas ago | 2
Change frame rate of video file
You are fully right. First read all the frames using the read command for VideoReader. Then make a VideoWriter object and use th...
alrededor de 16 horas ago | 0
How to optimise two variables at once
b = 166; %inertance c = 2000; %damping value lb = [0 500]; % lower bound ub = [500 3000]; % upper bound x0 = [b, c]; %...
alrededor de 17 horas ago | 0
| accepted
How to find every combination of values in a cell array?
One way, using allcomb: M = {[1,2,3], [4,5,6],[7,8,9]; [10,11],[12,13],[14,15]; [16,17,18,19,20],[21,22,23,24],[25,26,27,28]}...
3 días ago | 1
| accepted
function in matlap#
https://de.mathworks.com/help/matlab/ref/function.html https://de.mathworks.com/help/matlab/matlab_prog/create-functions-in-fil...
4 días ago | 0
How to ignore negative indices or assign it to zero in a loop
It is not needed to make the elements zero - they are already, because you preallocated y with zeros: x=[1 2 -1 -3 -4] h=[0 1 ...
5 días ago | 0
| accepted
Matlab schließt sich sofort nach dem starten wieder
Hallo, in diesem Forum wird fast ausschließlich auf Englisch geschrieben - was die Chance Deiner Frage beantwortet zu werden dr...
5 días ago | 0
Helo everyone, I want to ask about my error in matlab. Error: File: Untitled5.m Line: 57 Column: 56 -> (rand(1,nvar).*c1.*(pbest(pop,:)x(pop,:))+...) Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or
Line 36: for iter=1:maxiter for pop=1:maxpop % update velocity v(pop,:)=w*v(pop,:)+... rand(1,nvar)...
7 días ago | 0
Create Block Toeplitz Matrix
Try: rng(123) A = eye(3); B = randi(10,3); Omega = kron(A,B) gives: Omega = 7 6 10 0 0 0 0 ...
7 días ago | 0
How to prepare a matrix with variables that contain a range of values?
syms c s x % Tsigma Tsigma = [c^2 s^2 2*c*s; s^2 c^2 -2*c*s; -c*s c*s c*2-s^2]; Tsigma = subs(Tsigma,[s, c],[sin(x), cos(x)...
18 días ago | 0
Cubic funtion for interpolating
https://de.mathworks.com/help/matlab/ref/polyfit.html https://de.mathworks.com/help/matlab/ref/polyval.html
18 días ago | 1
Plot multiple probability distribution function side by side
% My code is not giving me what I want. pd1 = makedist('Normal') pd2 = makedist('Normal',2,1) x = -10:.1:10; pdf_x = pdf(pd1...
18 días ago | 0
| accepted
How to solve a linear system A * X = B when B and X are matrices instead as vectors?
linsolve can handle this. From documentation (Input Arguments): "...If B is a matrix, then each column in the matrix represents...
18 días ago | 0
I need to plot "e" by function of all values of "dm" i but can't do it please help
F=2000 ; dm=[12: 5: 37]; f=0.2 ; l=2 ; Q= ((F.*dm)/2)*((l+(pi*f.*dm)/((pi.*dm)-(f*l)))) ; e= (F*l)./(2*pi.*Q); % ^ ...
19 días ago | 0
| accepted
How to calculate the area of only white part in the image
Same as in your question yesterday: regionprops will solve both problems in 1 line of code.
19 días ago | 1
Error happen when doing optimization by using "surrogateopt"
f1 is a 2x1 vector - the objective of an optimization has to be a scalar. Thats the error. You need a criterion that expresses t...
19 días ago | 0
| accepted
How to concatenate a (REAL) string vector?
A=["abcd","efghijk"; "lm", "opkq"] B = A(:,1) + A(:,2) The more general solution (independent from number of rows or columns o...
19 días ago | 0
| accepted
How to insert a cell with string into a table as variable
The solution is inside the error message: B is a cell array of strings specify names in a string array or cell array of cha...
19 días ago | 0
| accepted
how to include a 'probability' when coding.
Use this every time you want to reward by random reward = rand(1) <= 0.6 reward = rand(1) <= 0.6 reward = rand(1) <= 0.6 rew...
19 días ago | 2
| accepted
Which is the most efficient way to solve a ODE that has a parameter that changes in every period?
Are gamma and beta parameters that result from the gamma / beta functions? Or just scalar parameters? I suggest using other name...
19 días ago | 0
| accepted
How to get certain matrix columns.
A = [1 2 3 4 5 6 7 8 9 10 11 12; 13 14 15 16 17 18 19 20 21 22 23 24] A1 = reshape(A',2,[]) b = A1(:,1:3:end) b = b(:)'
19 días ago | 1
| accepted
The end operator must be used within an array index expression.
See the original question - i fixed the error. frame = read(v,[600:600:end]); will not work in this case.
19 días ago | 1
| accepted
how to remove trailing zeros after rounding a matrix?
format short A = 1.23 format shortG A = 1.23
19 días ago | 0
How to extract a frame every 10 s from the video ?
https://de.mathworks.com/help/matlab/ref/videoreader.read.html#busxibt-2 In your case the interval to take the first frame afte...
19 días ago | 1
| accepted
matrix multiple rows with the same value
repmat([20:145:600],2,1)
19 días ago | 1
| accepted
not enough input argument error
timespan=[0 15]; y0 = [0 1 0 1 0 1]; [t,y] = ode45(@repressilator,timespan,y0); figure() plot(t,y) xlabel('Time') ylabel(...
20 días ago | 0
| accepted
Help: How to add a label (cell 1 x 20) to each bar (total 20 bars) in a bar plot where the bar plot has a 1x 2 dimension?
Try: labels=reshape({'A', 'B', 'C', 'D','E', 'F', 'G', 'D','A', 'B', 'C', 'D','A', 'B',... 'C', 'D','A', 'B', 'C', 'D'}',1...
20 días ago | 0
| accepted
How to calculate the center of white part?
Look at the regionprops examples.
20 días ago | 1
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