Torsten

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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...

2 days 前 | 0

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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,...

5 days 前 | 1

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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...

6 days 前 | 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...

6 days 前 | 1

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已回答
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...

7 days 前 | 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 ...

7 days 前 | 1

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已回答
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...

7 days 前 | 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(...

8 days 前 | 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...

8 days 前 | 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 days 前 | 1

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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 ...

11 days 前 | 0

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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...

13 days 前 | 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...

15 days 前 | 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...

16 days 前 | 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...

19 days 前 | 2

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已回答
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))]

19 days 前 | 0

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已回答
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,...

23 days 前 | 0

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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/...

26 days 前 | 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 %%%% ...

26 days 前 | 0

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已回答
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,...

28 days 前 | 0

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已回答
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(:,:...

29 days 前 | 2

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已回答
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...

29 days 前 | 0

已回答
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]);

29 days 前 | 0

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

30 days 前 | 0

已回答
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 ...

1 month 前 | 0

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已回答
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...

1 month 前 | 0

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using bvp5c evaluate velocity and temperature at specific points
yeval = deval(S,[-1,-0.4,0,0.4,1]); veval = yeval(1,:) thetaeval = yeval(2,:)

1 month 前 | 0

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已回答
Verifying my code for this problem, are these the right solution and graphs?
Look at the contour plot. The temperature at x = 0 should be at T_b = 50°C. This is not the case in your graphics. Maybe you int...

1 month 前 | 0

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Optimization method based on the Nonlinear least squares as well as fmincon for the defined objective function (Non-linear function).
You can add a multiple of the vector you obtain by the below command "double(null(A))" to "estimated_T", and you will still get ...

1 month 前 | 0

已回答
Error in ode45 and 'Events' of a Satellite Tracking Radar Model
The "tspan" vector you provide for "ode45" has no influence on the internal time steps taken by the integrator. In zones with st...

1 month 前 | 0

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