Torsten

Last seen: Today | Active since 2013

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Generalized Orr Sommerfield error returned in Eigs Function
I suggest you comment out the command W0 = @(x) lambertw(0,x); like %W0 = @(x) lambertw(0,x); include a function for W0 as ...

24 hours ago | 0

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How can i solve this problem' when i am running, this message appears: Failure in initial objective function evaluation. FMINUNC cannot continue.
Call your function in which you define the sum of differences squared between real and modelled data for the initial values of y...

1 day ago | 0

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hypergeom function, no output
The hypergeometric function has convergence criteria: Converges if p ≤ q and |z| < ∞. Converges if p = q + 1 and |z| < 1. For ...

1 day ago | 1

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How to plot a simple wave equation using method of lines?
n = 100; m = 100; tf = 1; dx = 1/n; x = linspace(0,1,n+1)'; tspan = linspace(0,tf,m+1); y0 = [sin(2*pi*x);zeros(n+1,1)]; %[t...

1 day ago | 0

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Analytical solution of 1-D transient heat transfer
I'd compare with the solution from "pdepe": m = 1; Ri = 0.05; nd = 20; r = linspace(0,Ri,nd); t = [0 100 600 1800 3600 5000...

2 days ago | 0

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Solve Nonlinear ODE Symbolically
This is a nonlinear system of ODEs. An analytical solution with symbolic math is not possible. The only way to solve it is nume...

4 days ago | 1

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Triple intergral for the array valued function
N = cell(2,3); N{1,1} =@(x,y,z) x.^2+y.^2+z.^2; N{1,2} =@(x,y,z) x.^2+y.^2+z.^2; N{1,3} =@(x,y,z) x.^2; N{2,1} =@(x,y,z) y....

4 days ago | 0

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does "generalized Neumann" boundary condition include actual Neumann boundary condition?
Is there maybe a workaround (like change of variables) to solve these problems? No. All Neumann boundary conditions are related...

4 days ago | 0

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Graphing 1D Diffusion in 2 Compartments - Possible Issue with ODE solver
In my opinion, you have the following conditions at the interface x = h_D: (1) D_D*dC_D/dx = D_R*dC_R/dx (2) C_R = phi*C_D (or...

5 days ago | 0

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I want to optimize an ODE system of equations with constraints
I ran your code with k in the order of 0.1,1 and 10, but it seems the k-values have amost no influence on the result of the inte...

5 days ago | 0

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Solving edge-value problems with unknown intervals
Define a dimensionless variable x' = x/l1 and transform your equation to the form dY/dx' = ... which has to be solved in [0 1]. ...

5 days ago | 0

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How to calculate a composite triple integral with exponential function?
Setting l, r and s to zero will cause problems because you divide by these variables. But also changing integral2(@(s,l)array...

5 days ago | 0

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Error using lsqncommon Lower and upper bounds not supported with complex-valued initial function or Jacobian evaluation.
If you use "fmincon" and (f(x,xdata)-ydata)' * (f(x,xdata)-ydata) as objective function, complex numbers don't matter because th...

6 days ago | 0

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Solve a complex differential equations system
The main problem with your equations is that they involve a term that has to be evaluated at a boundary point. Otherwise, you co...

6 days ago | 0

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an ode with arguements
You have to define your vector of solution variables as y(1) = f, y(2) = f', y(3) = f'', y(4) = T, y(5) = T' and your function...

6 days ago | 0

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How to invert a square matrix using Gaussian elimination
The newton update is x_(n+1) = x_n - Df^(-1)*f, not x_(n+1) = x_n + Df^(-1)*f. But you should not explicitly compute the ...

7 days ago | 1

Answered
Find Eigenvalues of ODE45 Solution MATLAB
Your system reads z1'= z2 z2' = ( F-(c1+c2)*z2-( ((k1*gamma1+k2*gamma2)*z1^2+k1+k2)*z1+(-k2*gamma2*z1^2-k2)*z3 ) )/m1 z3' = z...

7 days ago | 1

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Answered
How to get an expression for a Hypergeometric function with symbiotic variable
MATLAB is not able to find the Inverse Laplace transform of such a complicated function as an analytic expression.

7 days ago | 0

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Answered
can someone please help me coding this saturation equations in matlab
m, umax and u have to be defined previously. psi = zeros(m,1); idx = abs(u) > umax; psi(idx) = sign(u(idx)).*min(abs(u(idx)),...

7 days ago | 0

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Answered
variable problem of GA
t=[0.015 0.01 0.009 0.012 0.016 0.014 0 0]; w=[0.005 0.004 0.003 0.004 0.006 0.004 0 0]; options = optimoptions( ... 'ga'...

7 days ago | 0

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Answered
fmincon solution does not differ from initial guess if I provide gradient
Use SpecifyObjectiveGradient Gradient for the objective function defined by the user. See the description of fun to see how to...

7 days ago | 0

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When using integral function to calculate MeijerG function, Matlab will get stuck.
meijerG has a division by 0 at SNR = 0. If you are sure the integral exists at SNR = 0, start with a small value > 0, e.g. aver...

8 days ago | 0

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Answered
Set answers of first BVP as new boundary condition for second BVP
"value_at_1" is defined in the script part of your code, but it's not automatically visible in the functions you define. Either ...

8 days ago | 0

Answered
lsqcurvefit can't get to the right values
It seems that a variation of your parameters has almost no effect on epsilon_equation. This makes lsqcurvefit assume it cannot m...

9 days ago | 0

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cumprod fuction in GA
Note that Nb was not defined in your code - I added it to the known arrays. rng("default") t=[0.015 0.01 0.009 0.012 0.016 0.0...

10 days ago | 0

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Answered
cumprod fuction in GA
Your call to ga is wrong: x(1), x(2) and x(3) do not belong there, idx is undefined, lb and ub have 2 elements instead of 3, [...

10 days ago | 0

Answered
if number of steps is not multiple of 3 how to do simpsons 3/8 rule? why im getting more error in simpsons 3/8 rule than in simpsons 1/3 rule?
if number of steps is not multiple of 3 how to do simpsons 3/8 rule? The 1/3 rule can be used for the remaining subintervals wi...

12 days ago | 0

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Answered
showing error " Array indices must be positive or logical values"
lambda=sigma.*a.*((sqrt(1+32.*theta.*r)./(sigma(i).*a))-1) instead of lambda=sigma.*a((sqrt(1+32.*theta.*r)./(sigma(i).*a))-1)...

12 days ago | 1

Answered
how to format the codes to compute the differential-algebraic equations using ode15s?
I don't see a way to use a MATLAB ode integrator to solve your system. Take a look at http://www.unige.ch/~hairer/software.htm...

12 days ago | 0

Answered
How to write a Matlab code for a sequence of functionals and their minimums
Your code: number_of_iterations = 3; A = @(alpha) ...; % Your NxN matrix A depending on alpha u = ...; % Your Nx1 ...

13 days ago | 0

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