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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 ...

19 giorni fa | 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...

20 giorni fa | 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...

21 giorni fa | 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.

21 giorni fa | 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 % ...

21 giorni fa | 3

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

22 giorni fa | 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) ...

22 giorni fa | 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;

22 giorni fa | 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...

22 giorni fa | 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

22 giorni fa | 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 ...

22 giorni fa | 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...

25 giorni fa | 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....

27 giorni fa | 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...

28 giorni fa | 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...

29 giorni fa | 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))

circa un mese fa | 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...

circa un mese fa | 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...

circa un mese fa | 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 ... ...

circa un mese fa | 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...

circa un mese fa | 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...

circa un mese fa | 0

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How to draw the function relationship graph between two or three variables, where these variables are solved by a system of equations.
Here are the three possible solutions for VL given tc. % 定义符号变量 VL=20; syms tc t2 Q_out Vco Vcn VL %参数关系 L=100e-9; C=50e-6...

circa un mese fa | 0

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Plotting a variable versus space and time
Use "slice": https://uk.mathworks.com/help/matlab/ref/slice.html

circa un mese fa | 0

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checkGradients, but the objective function has two inputs: x and xdata?
valid = checkGradients(@(p)semiCircle(p, Q),p0)

circa un mese fa | 0

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How can I evaluate the transition matrix using the fourth order Runge-Kutta ODEs
Seems to work. What's your problem ? Don't use the transition matrix to integrate in one pass. If you have to, generate it with...

circa un mese fa | 0

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problem with vpa and symsum
The numerical bessel functions are not able to compute your sum correctly (for higher values of k, they return NaN) (see below)....

circa un mese fa | 0

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getting singular jacobian error while using bvp4c solver
I can't interprete your solution curves, but it seems to be a problem for the solver that the Scaled Mass goes to 0 with increas...

circa un mese fa | 0

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Empty sym: 0-by-1 : Don't understand why
I multiplied by the denominators and squared to get rid of the square roots. Your system seems to have 4 (complex-valued) solut...

circa un mese fa | 0

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Non-linear least squares estimation with linear constraints in Simulink?
I vaguely remember that using "lsqcurvefit" within Simulink requires to use the Levenberg-Marquardt algorithm. I can't answer wh...

circa un mese fa | 1

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Do I have a convergence issue?
B0 = 0.5; B = fsolve(@fun,B0) function residual = fun(B) g = 10; %m/s^2 Q = 70*1000; %N/m tau_L1 = 24*1000; %Pa t_w = 30...

circa un mese fa | 0