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How to set Drichlet and Neumann boundary conditions for a set of ode in BVP solver
Is there a possibility that I can set three boundaries (mix between Drichlet and Neumann boundary) for a set of two ODE's? No....

7 Tage vor | 0

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Trying to determine roots of this polynomial (Det)
k = [1750 -750 0; -750 1250 -500; 0 -500 500]; m = [75 0 0; 0 75 0; 0 0 50]; eig(k,m)

7 Tage vor | 1

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Civil engineering coding problem ( I dont know where the problem in my code is and how to solve it, thanks in advance )
"coord" has only three rows, but you try to access coord(4,1) and coord(4,2) which do not exist (see above).

7 Tage vor | 0

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Why I am getting this error message? How to fix it?
Maybe you mean this function: function v = vec(m) %Helper function to turn a matrix of any size into a column vector using (:)...

7 Tage vor | 1

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How to draw a three-dimensional function image corresponding to the analytic expression of a given piecewise function image
f = @(x,y)(4*y-4*x.*y-2*y.^2).*(y<x).*(x+y<1)+2*(1-x).^2.*(y<x).*(x+y>=1)+(4*y-4*y.^2-2*x.^2).*(y>=x).*(x+y<1)+(2-4*x+4*x.*y-2*y...

8 Tage vor | 0

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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 ...

9 Tage vor | 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...

9 Tage vor | 1

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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 ...

9 Tage vor | 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...

9 Tage vor | 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...

10 Tage vor | 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...

11 Tage vor | 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....

11 Tage vor | 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...

12 Tage vor | 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...

12 Tage vor | 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...

12 Tage vor | 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]. ...

12 Tage vor | 1

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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...

12 Tage vor | 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...

13 Tage vor | 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...

13 Tage vor | 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...

14 Tage vor | 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 ...

14 Tage vor | 1

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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...

14 Tage vor | 1

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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.

14 Tage vor | 0

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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)),...

14 Tage vor | 0

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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'...

14 Tage vor | 0

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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...

15 Tage vor | 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...

15 Tage vor | 0

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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 ...

15 Tage vor | 0

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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...

17 Tage vor | 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...

17 Tage vor | 0

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