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# Stephan

##### Last seen: Today
1.180 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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How to use fsolve when a nonlinear equation given two arrays of parameters (not the variables)? Why can't I use for loop?
Hi, you could try to vectorize your function in order to avoid for loops - here is a simple example: % Constant 1 as a row vec...

15 días ago | 0

Question about GA and the fun.
Have a read here: https://de.mathworks.com/help/optim/ug/passing-extra-parameters.html In your case it should look somehow lik...

15 días ago | 2

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Help me I am unable to input array
They way you coded it needs to enter the single values one after each other: Enter elements of x=1 Enter elements of x=2 Ente...

16 días ago | 0

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Problems using LSTM with PPO Agent - Error: Invalid input argument type or size such as observation, reward, isdone or loggedSignals.
I finally could solve the issue. The problem was that there were 2 LSTM layers in the network, which led to the error: Caused b...

19 días ago | 1

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Question

Problems using LSTM with PPO Agent - Error: Invalid input argument type or size such as observation, reward, isdone or loggedSignals.
Hi, i implemented some RL agents (DQN, AC, PPO...) successfully with my custom environment function by using a feedforward netw...

21 días ago | 1 answer | 0

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numerically solving an equation involving a matlab function with multiple variables
fun = @(x) blsprice(5,2,0.05,x,0.2) - 4; unknown_time = fsolve(fun,0.5)

alrededor de 1 mes ago | 1

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I want to get 2d image from a sensor data.What matlab commands convert a dataset to images?
A = rand(100,100) imshow(A) or A = (randi(1500,100,100))-750 image(A)

alrededor de 1 mes ago | 0

How can I name matrices generated by a for loop as Z1,Z2,Z3 ...etc.
There are a lot of contributions (one of the best is here) which show why this way of coding is bad - use an efficient way by in...

alrededor de 1 mes ago | 1

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Problem with solve matrix
For me your code works: disp('An economic system composed of 3 sectors has the input-output matrix'); D=[0.5,0.1,0.1;0.2,0.5,0...

alrededor de 1 mes ago | 0

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ode45 solver code for solving a system of three coupled equations does not work
Your ode appears to be stiff - therefore i recommend to use ode15s instead of ode45. Also the behaviour of your system can be se...

alrededor de 2 meses ago | 1

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i want to read a csv file and store as rows and columns of a cell
fileID = fopen('FOM_HFA_Pavg.csv'); content = textscan(fileID, '%s','Delimiter','\t'); fclose(fileID); content = content{:}; ...

alrededor de 2 meses ago | 0

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calculate and plot the following differential equation using ODE45solver.
y0=0.5; %intial value h=0.8; % t=[0 4]; %tspan [t,y] =ode45(@(t,y)-y+sin(t), t,y0); plot(t,y,'-o'); xlabel('time'); ylabel...

alrededor de 2 meses ago | 0

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using Q learning agent for continuous observation space
You also are allowed to write a custom critic function: https://de.mathworks.com/help/reinforcement-learning/ref/rlqvaluerepres...

alrededor de 2 meses ago | 0

Your code works - you only need to call your function and plot the results: % Call the function and save results in W and Fa [...

alrededor de 2 meses ago | 0

Calculate a letter from equation with letters.
You might want to do this: syms Xe Ye a1 a2 cos1 cos2 sin1 sin2 eq(1) = Xe == a2*(cos1*cos2-sin1*sin2)+a1*cos1; eq(2) = Ye ==...

alrededor de 2 meses ago | 0

FZERO cannot continue because user-supplied function_handle ==> @(M)FindM(M,N(k),Q,wn(i)) failed with the error below.
Declare the code in findM_1P as a function and give it proper input and output arguments, to make it possible for fzero passing ...

alrededor de 2 meses ago | 0

IMRT Beam angle optimization
You might want to read the dissertation from Mark Bangert, which includes a rich bibliography: http://archiv.ub.uni-heidelberg....

2 meses ago | 0

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Error in bin2dec ?
You are not doing wrong - just read the documentation: "...If the input argument D has a value greater than the value returned ...

2 meses ago | 1

Combining 3 curves into 1 average
Here is a simple example: % fantasy times times1 = 1:10 times2 = 1:2:11 % fantasy values y1 = 2 * (1:10) y2 = 4 * (1:2:1...

2 meses ago | 0

A problem while using lsqnonlin
Use the same random numbers for the same results: rng('default') d = linspace(0,3); y = exp(-1.3*d) + 0.05*randn(size(d)); ...

2 meses ago | 0

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I used nested functions - for 2 of the constants you did not provide values: % Call the outer function finalprogramme %% Ou...

2 meses ago | 0

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Environment Reinforcment learning Matlab
See this link to the documentation: https://de.mathworks.com/help/reinforcement-learning/ug/create-custom-reinforcement-learnin...

2 meses ago | 0

Custom Environment for Reinforcment learning
There is a step-by-step example in the documentaion: https://de.mathworks.com/help/reinforcement-learning/ug/create-custom-rein...

2 meses ago | 0

You need to perform a inverse laplace transformation: num=134; den=[1 16 134]; x=tf(num,den) subplot(1,2,1) step(x) title(...

2 meses ago | 1

write function that generates an echo to audio
Hi Franziska, there is no need for loops: % Load sample sound load TestSoundEcho.mat; % Play sample sound sound(data, fs)...

2 meses ago | 0

Output a solution for a function at a specific value input
magT = @(omega)sqrt((5.903*10^24)^2+(1.181*10^20*omega)^2)/sqrt((1.181*10^25-(2.361*10^16*omega^2))^2+(9.445*10^20*omega)^2); ...

2 meses ago | 0

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solving integral in matlab
What you are looking for is an analytical solution. The integral function does solve numeric. To solve symbolic use int as John ...

2 meses ago | 1

Split data into groups
A = randi(5000,300,1); % random data A = sortrows(A); % sort it low = A(1:100); % just use indexing now mid = A(101:200); hi...

2 meses ago | 0

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Syntax error when opening a file using a path. it says " use a newline, semicolon, or comma before this statement "
It is unclear what you want: maybe you forgot to underline your variable name function_data = angleAnalysis_withPlots('C:/rese...

2 meses ago | 0