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# Torsten

Last seen: Today Active since 2013

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Trouble using lsqnonlin to fit the IV curve of a solar cell
You did not include global V Voc Jsc T k q J in the script part. clc clear global V Voc Jsc T k q J %reads input file ...

15 hours ago | 0

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How do I represent this sym function as a written formula
syms s f = vpa(ilaplace(1/((s+7)*(s^3+4*s^2+6*s+5))),4)

16 hours ago | 0

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Invalid use of operator. error, dont know what to change to fix it.
Elementwise operations are .* ./ and .^ .) does not exist. f = (x.^2).*exp(-x)

16 hours ago | 0

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I want to check if something algebraically simplifies to 0 when i sub in values
Euler equations of gas dynamics ? Eigenvalues and Eigenvectors of the Jacobian are well-studied. Why reinvent the wheel ? syms...

18 hours ago | 0

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How do I solve a linear optimization problem with a constrained output?
Define the X to be solved for as X = (u,x).Then you can constrain x according to your needs and continue using "linprog".

19 hours ago | 0

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ODE45 - must return a column vector.
B = readtable('t13.xlsx'); t13 = table2array(B); c = readtable('ambient.xlsx'); ambient = table2array(c); d = readtable('sol...

24 hours ago | 0

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How to solve optimization problems when the objective function includes a symbolic function
The usual way to deal with this problem is to define Func2Var1 and Func2Var2 as additional optimization variables and to specify...

1 day ago | 1

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Plot a graph from arrays
plot(hv, cell2mat(Xm))

2 days ago | 0

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Function with many outputs
X=ga(@cost,numel(X)); function J = cost(X); [Y_1,Y_2] = MyFun(X); J = Y_1.^2+Y_2.^2; end

2 days ago | 0

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Answered
Trial and error problem
The results are not convincing, but that's the way to go with three data points. fun1 = @(x)[0.0701-x(1)*exp(x(2)/(293.65-x(3))...

2 days ago | 0

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How to plot a graph correctly?
Try "fimplicit".

2 days ago | 0

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Why cant I get a stable Cranck Nicolson discretization?
We use a Dirichet boundary condition so that x=0 for t = 0 and a = 0. And which conditions at a = a_end ? Try "pdepe". If th...

2 days ago | 0

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Optimising Limits of Chain integrals
fun1 =@(g1) 208.4*exp(-0.02704.*g1)-293.9*exp(-0.1286.*g1); fun2 =@(g2) 108.3*exp(-0.01137.*g2)-622.8*exp(-0.1578.*g2); A = ...

2 days ago | 1

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Answered
Is it possible to add more constraints than the default ones in LSQLIN function?
Use "fmincon" with the constraint (C*x).*d >=0 and define this constraint in function "nonlcon".

2 days ago | 2

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How to solve error using integral (line 83) first input argument must be a function handle?
T = 1; m = 64; x = 1:0.1:2; y = 2:0.2:10; [X,Y] = meshgrid(x,y); g = @(u)sin(2*pi*u); phi = @(t,x,y) ((sign(x/y+g(t/T)).*(...

2 days ago | 0

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Double monod maximum rate estimation
% Initial guess for rmax rmax0 = ...; % Time is a (nx1) vector, % Sdata is a (nx2) matrix with measurements of c_CH4 (1st c...

2 days ago | 0

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Answered
How to calculate the symbolic integration of rational functions?
syms x f = x^4+x^3+x^2+x+1; fp = partfrac(1/f,x,'FactorMode','real') int(fp,x,0,1) vpaintegral(1/f,x,0,1) f = matlabFunctio...

3 days ago | 3

Answered
I couldn't understand why this program took a long time to run, can anyone help me to solve the problem so that the code can run fast
The reason is this line: U = sort(rand(1,20).*(0.005)+rand(1,20).*(0.003),'ascend'); MATLAB integrators are not suited to cope...

3 days ago | 0

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Trying to use Newton's method until solution converges
% Variables Eps = 0.011; E = 73100; H = 662; n = 0.07; maxIter = 100; % # of iterations Tol = 1e-8; i = 1; error = 1.0; ...

3 days ago | 0

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Answered
Solve System of Equations to calculate the inverse kinematics
X = cos(q1)*(cos(q2 + q3) + cos(q2)); Y = sin(q1)*(cos(q2 + q3) + cos(q2)); Z = sin(q2 + q3) + sin(q2) + 1/5; Dividing equati...

4 days ago | 1

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I have a problem with solve command
syms x y [x y] = solve([3*x-y==2,x+y==1])

4 days ago | 0

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Write a row and column vector as matrix index
a = [4 5 3]; % Generate index vectors A and B [A,B] = ndgrid(a,a); A = A(:) B = B(:) % Use A and B as index vectors for a m...

4 days ago | 1

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Answered
3D Contour plot. Filled slices/surfaces are black
The mesh lines are black and cover the colors. To remove them, use gr = slice(Xg, Yg, Zg, Vg,[],[],zslice); set(gr,'Edgecolor...

6 days ago | 0

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Hoe can I convert my script to a function?
If the coefficients don't change in the course of the simulation, you should read "Coefficient.mat" only once and pass the matri...

6 days ago | 0

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Answered
a = b<0
"a" is a logical variable. It is set to "true" (=1) if b<0, else it is set to "false" (=0). The next operation c = 3*a works a...

6 days ago | 2

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How to compare previous results in iteration?
You should never check whether two variables are equal. Always check whether they are approximately equal: difference = 1.0; o...

6 days ago | 1

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Euler method: ODE with different initial conditions
Y0 = 0.5:0.05:1.5; hold on for i = 1:numel(Y0) y0 = Y0(i); [x,y] = euler(y0); plot(x,y) end hold off functio...

7 days ago | 0

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Answered
The solve function doesn't work properly
syms l1 l2 l3 H B phi gamma theta eq1 = l3*cos(gamma) - l2*cos(phi) + l1*sin(theta) + B == 0; eq2 = l3*sin(gamma) - l2*sin(ph...

8 days ago | 0

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How can I avoid looping here?
STD_w=0.05; STD_gama=5; mean_w=linspace(15,40,10); sigma_w=ones(1,length(mean_w))*STD_w; mean_gama=linspace(115,85,10); sig...

8 days ago | 0

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Answered
Partial Least Squares regression - confidence interval of the predicted variable (response)
I did not look into your code in detail, but I think you could use the output structure "gof" from MATLAB's "fit" together with ...

8 days ago | 0

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