Risposto
Average Flux Across Edge
Should be averageFlux = 1/(Nodes_Xa(end)-Nodes_Xa(1))*trapz(Nodes_Xa,flux_Xa)

10 mesi fa | 0

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What do you think of my numerical Jacobian, using the central-difference method?
It cannot be correct because F1,...,F6 are scalars, not functions. And if F1,...,F6 were functions, the 2*h expression must be...

10 mesi fa | 0

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How should I compute the Jacobian for my equations of motion?
According to your description, at some stage of your procedure, the right-hand side of your ODE system is available as a symboli...

10 mesi fa | 0

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Trouble animating a double pendulum
theta_1 = 19*pi/180; theta_2 = 30*pi/180; l_1 = 1; l_2 = 1; g = 9.8; m_1 = 1; m_2 = 1; M = m_1 + m_2; dt = .00...

10 mesi fa | 0

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Numerical Methods for Singular systems
The loop index i does not equal time t. So expressions like d_1=floor(1.5+sin(0.5*i*h)); x1(:,i-d_1-1) x2(:,i-d_1-1) x3(:,i...

10 mesi fa | 1

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Does anyone know how to use an IF statement with ODE's? I am trying to create an IF statement sigma > 0 , tau > 0 if dx(3,1) > 0, dx(1,1) > 0 and sigma = 0 , tau = 0 otherwise
You mean % linear ODEs dx(1,1) = alpha * y - beta * r * y; dx(3,1) = - theta * w + lambda * y * w - mu * w * w; if dx(1,...

10 mesi fa | 2

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Integral Recurrence Formula Implementation
This seems to work: xl = 0; xu = 4; q = 12; C1 = 2; vl = (xl*sqrt(xl^2+C1^2)+C1^2*log(xl+sqrt(xl^2+C1^2)))/2; vu = (xu*sqr...

10 mesi fa | 0

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How to solve a thermal model? NEED HELP!!
Params = load('Params.mat'); S_matrix = load('S_matrix.mat'); MC = Params.MC; Q = Params.Q; S = S_matrix.S; T0 = 298.15; T...

10 mesi fa | 1

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Risposto
Apply Dirichlet BC on Vertex
Is there a way to use a function and logic (example below) to have the code use Neumann on edges 1 & 4 but when x=xmax and y=ymi...

10 mesi fa | 0

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I have a problem with 2D heat conduction develop a computer code to solve the 2D heat conduction equation:∂2T /∂x2 + ∂2T/ ∂y2 = 0, gradient don't change when iterations increase, please help me
The maximum gradient is always in the left and right upper corner point with value (1-0)/(1/40) = 40. So it won't change in the ...

10 mesi fa | 1

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Risposto
How to solve a thermal model? NEED HELP!!
I get these curves with your equations and your data. T0 = 298.15; T_air = 293.15; G_air = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 22...

10 mesi fa | 0

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quadgk AbsTol/RelTol parameters combinations
umin = 1e-16; f = @(t,u) exp(-t*u.^2)./(u.*(besselj(0,u).^2+bessely(0,u).^2)); g = @(u) pi/2 * atan((2*double(eulergamma)-log(...

10 mesi fa | 0

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Solve not returning values after first iteration?
You overwrite omega3 and omega4 as symbolic variables with numerical values. Replace % Solve the system sol = solve([eq1, eq2...

10 mesi fa | 0

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BVP unknown parameter 2 column vector
You forgot to include "C_L_aoa" as global variable in the script part of your code. clear all clc close all %%%%%%%%%%%%%%%%...

10 mesi fa | 1

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Risposto
Nonlinear Curve fitting with integrals
This code works for your supplied data: Delta = 0.075; delta = 0.002; D = 0.098E-9; gamma = 2.675E8; Rmin = 0.01e-6; Rmax ...

10 mesi fa | 0

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Risposto
How to graph coupled differential equations
% Parameters m1 = 4.0; m2 = 6.0; L = 1.5; k = 100.0; % Added missing parameter g = 9.81; F0 = 100; tF = 1; % Initial st...

10 mesi fa | 0

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Nonlinear Curve fitting with integrals
It takes too long to run the code online - try if it produces reasonable results. Maybe you have to set lower and upper bounds f...

10 mesi fa | 0

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Matlab function that tells the full path of from where the function has been called
What about passing the full path where the function is located from the respective functions 2,3,4,5... to function1 ? See htt...

10 mesi fa | 0

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how to deal with discontinuities in solutions to differential equations using ode45
Usually, the differential equations to be solved are much more complicated than yours which makes it impossible to foresee possi...

10 mesi fa | 2

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Risposto
How to rename a new matrix obtained by adding a row to the previous matrix
A = [1:5; 6:10] B = [A;11*ones(1,size(A,2))]

10 mesi fa | 0

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Risposto
eventfunction for stopping solver when output becomes complex doesn't work
Try options = odeset('Events', @(t,y)stop(t, y, Vb0, lambda, mb, rhog0, Cw)); [t, y] = ode45(@(t, y) DE(t,y, Vb0, lambda, mb,...

11 mesi fa | 0

Risposto
Drawing Bessel function is not possible in that it give me an error
Maybe this is what you want: x=(0:0.01:5).'; i=0:20; hold on for m=0:5 j=sum((-1).^i./(factorial(i).*gamma(i+m+1)).*(x/...

11 mesi fa | 0

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Facing problems in nonlinear system
"pdepe" gives a different solution than your method. Maybe the nonlinear systems have multiple solutions. %%%% Problem_01 %%%% ...

11 mesi fa | 0

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Risposto
How to code a 1D ODE in MATLAB
Usually, the equation reads dW/dt + U*dW/dx = C (1) If U in this equation is positive, your flow goes from left to right,...

11 mesi fa | 0

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Risposto
lsqcurvefit Surface Fitting Troubleshooting
There is a problem with your "poly_fun". You have to use poly_fun = @(c,XY) c(1)*XY(:,:,1).^1 + c(2)*XY(:,:,2).^1 + c(3)*XY(:,:...

11 mesi fa | 2

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Risposto
I have this system of linear equations and i need to solve it for unknowns. how i can solve it in MATLAB? we have 8 unknowns and 8 equations.
@javeria If you want to avoid writing your system as A*X = B, you can use a nonlinear solver like "fsolve". As the system is l...

11 mesi fa | 0

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Finding one real solution with vpasolve
lambda = vpasolve(LCG/B*1/lambda_t==0.75-1/(5.236*CV^2/lambda_t^2+2.4) == 0, lambda_t, [0,inf]);

11 mesi fa | 0

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make function from matrix
t = linspace(0,10,3000).'; a = rand(3000,1); f = @(x)interp1(t,a,x); f(8.336)

11 mesi fa | 0

Risposto
I am struggling to format and run a pde as part of a liquid-liquid packed column
K_M = 0.1252; xb_meth = 0.0054; Rho_FAME0 = 0.915; Phid_cho = 0.2352; Vd = 6.1006e-4; kod_meth = 1.0157e-5; ap = 204; Vc ...

11 mesi fa | 0

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trouver un angle avec l'equation de trajectoire d'un projectile
x0 = 0.08; y0 = 0.05; v0 = 2; g = 9.81; syms t x theta eqn1 = x == v0*t*cos(theta) + x0; eqn2 = 0 == v0*t*sin(theta) - 0.5...

11 mesi fa | 0