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Can anyone help me to run this coding?
OdeBVP returns NaN for ff(3) at the start (see above). You will have to find out the reason (initial values for y, x, parameters...

1 year ago | 0

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Trying to create code which solves a BVP using a second-order finite difference scheme and Newton-Raphson method
% Code to calculate the solution to a % nonlinear BVP with Dirichlet and Robin BCs % Some physical parameter. mu = 10; % De...

1 year ago | 0

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finding the value at a specific time from second-order ODE
The easiest (maybe slightly inaccurate) way is to use interpolation: f_conv = interp1(time,x,2.5) f_ode45 = interp1(time,y(:,1...

1 year ago | 2

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Inverse fft doesn't match analytical formulation
syms w F = 1/w^2; ifourier(F); disp(char(ans))

1 year ago | 1

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How do I convert symbolic values to numerical for uitable ?
syms x f = x^2-2; xsol = solve(f==0) class(xsol) xvpa = vpa(xsol) class(xvpa) xnum = double(xsol) class(xnum)

1 year ago | 0

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I am getting the error message "unable to find symbolic solution" using dsolve.
What exactly am I doing wrong? Nothing. "dsolve" is simply not able to find an analytical solution because the problem is too ...

1 year ago | 0

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I keep getting the "not enough inputs error" and I don't know how to fix it
m1 = 135; m2 = 30.3455; w1a = .220; w1w = .780; w1m = .000; w2m = .202; w2w = .798; w2a = .000; syms x [6 1]; F(1) = w1...

1 year ago | 0

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Nonlinear constraints depend on the output of optimization objective
Define the constraints using a lower bound of 0 for x(1) (you can prescribe this in the array lb) and one linear constraint (you...

1 year ago | 1

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Solving ODE with explicit equations
If you have a mixture of differential and algebraic equations, you need to define the mass matrix appropriately. In your case -...

1 year ago | 1

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Error in running the Example script of pdepe
As you can see, the code runs under MATLAB R2024b (and should be no problem under R2023b, too). I suggest contacting Technical ...

1 year ago | 0

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How to optimize an reduce the computation time
I don't understand the sense of your while-loop. If you want to define Psat as a function of fg, the problem becomes more compl...

1 year ago | 0

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How to convert symbolic expression to numeric?
integrand_num = matlabFunction(subs(simplify(integrand))) gives you a function handle with y as input argument (see above). A...

1 year ago | 0

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Concerned that matlabFunction( ), when converting from symbolic to numerical, changes the sizes of matrices and vectors,
As you can see M = reshape([...],[3 3]) Thus the expression in [ ] is 1x9, but it is finally reshaped to 3x3.

1 year ago | 1

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Cannot subtract number of order smaller then e-4 from variable
It's just a question of how the numbers are displayed. Internally, the precision of computing is much higher. format long % ...

1 year ago | 3

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Reduce the size of Matrix from 100x100 to 35x11
x1 = x1(1:35,1:11)

1 year ago | 0

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best combination for lowest possible dose and lowest possible material cost
You mean bestDoseRate = Inf; bestCost = Inf; for index = 2:9261 if (mixDoseRate(index) <= bestDoseRate && mixCost(index) ...

1 year ago | 0

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RK4 help (someone help fix this)
Use for i=1:n_nodes-1 instead of for i=1,n_nodes-1;

1 year ago | 2

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Solving a set of complex trig equation
Do you see the problem ? Your R-values and your y- and z-values are not compatible (at least for n = 3). It must hold that R_v...

1 year ago | 0

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Warning: Non-finite result. The integration was unsuccessful. Singularity likely. > In integral2Calc>integral2t (line 131)
fun(Phi0(1),Phi0(1)) gives NaN + 1i*NaN

1 year ago | 0

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How to solve rachford - race function using newton method
Multiply the equation by product_{i=1}^{n_c} (1+f_Rg*(K_i-1)). This gives you a polynomial of degree n_c-1 in f_Rg which can be ...

1 year ago | 0

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How can I evaluate the transition matrix using the fourth order Runge-Kutta ODEs
If it's still of interest: this code seems to work correctly. I don't know why using n = size(A,1); E = A(t+dt/2)*(eye(n)+dt/2...

1 year ago | 0

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Why do I receive error using BVP5C "The boundary condition function BCFUN should return a column vector of length 1"?
You have one first-order ODE, but two boundary conditions. That's mathematically impossible - you can impose only one condition....

1 year ago | 0

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Event function and ODE.
Don't use both events simultaneously in your event function. Start the solver with the first event function and integrate until...

1 year ago | 0

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Trouble solving system of pdes with pdepe
"pdepe" is a solver for parabolic-elliptic partial differential equations. The positions with zero elements in the f-vector indi...

1 year ago | 0

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Solving the differential equation gives unexpected results. How to fix that?
Better ? v(t) = v(0) - g*t - v0*log(m0/(m0-k*t))

1 year ago | 0

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Define function for transient transient boundary condition
F1= 3.843e-8; F2= -3.482e-5; F3= 1.179e-2; F4= -1.95; F5= 23.69; Trefrig = @(location,state)F1*state.time^4 + F2*state.time...

2 years ago | 0

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How to write an event function to stop at second or third x axis crossing.
I'd make the solver stop at each x-crossing. After it returns control to the calling program, add 1 to the number of crossings a...

2 years ago | 0

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Why don't I need a comment character after an (...) ellipsis?
Most probably there is the convention that ... is the symbol to connect two subsequent lines and that everything behind the ... ...

2 years ago | 1

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AYUDA EN CODIGO DE MATLAB PARA UN ESTRUCTURA DE PUNETE EN 3D
If you insert the lines % Calcular desplazamientos en los grados de libertad libres rank(K_aa) size(K_aa) before the command...

2 years ago | 0

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Why Is Colon Operator Not Equivalent To linspace Command?
Both arrays seem to be generated differently such that floating point issues come into play: z1 = 0:.08:50000; z2 = linspace(0...

2 years ago | 0