Answered
Solve BVP with Arrays as Coefficients
If you have functions depending on x for a, b and f, you are done. If not, you can try the following: Use "interp1" to interpo...

1 year ago | 0

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Answered
Why the integration can not be calculated out correctly?
That's the best you can get, I guess: V = 0.46:0.01:1; for i = 1:numel(V) v = V(i); lower_x = 9.578251022212591 - v; ...

1 year ago | 0

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Answered
Not exactly the exact answer using Symbolic Math Toolbox
syms t f = sin(t); frms = sqrt(1/(2*sym(pi))*int(f^2,t,[0 2*sym(pi)])) % rms value from definition

1 year ago | 1

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Answered
How to implement time dependent heat generation
I leave the rest to you: %% Create thermal model PDE thermalmodel = createpde(1); %% Create Geometry R2= [3,4,-1.5,1.5,1...

1 year ago | 0

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Answered
2 eqns in 2D with different BCs applied to each variable on the same edge? On E1, u1=0 and du2/dn=0, on E2 u2=1 and =du1/dn=0. The solution is all zeros. Example code is below
I think applyBoundaryCondition (model, "mixed", Edge=1, u=0, EquationIndex=1,q=[0 0;0 0],g=[0;0]); applyBoundaryCondition (mod...

1 year ago | 0

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Answered
Error msg: Undefined function or variable 'optimproblem'. Error in optimize_plant_operation (line 6) prob = optimproblem('ObjectiveSense', 'maximize');
"optimproblem" was introduced in R2017b: https://uk.mathworks.com/help/optim/ug/optimproblem.html at the bottom of the page un...

1 year ago | 0

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Computing velocity with Forward Euler method
@Riccardo Are you sure you can leave temperature fixed with a pressure difference of 12 bar ? And did you try plotting your re...

1 year ago | 0

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model non-autonomous system with neural ode
You can easily convert your non-autonomous system into an autonomous one by defining an additional ODE y2 as dy/dt = y2, y(0...

1 year ago | 0

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Answered
Orthotropic Conductivity on Face
I found orthoK = [0.75*kappa; 0.85*kappa]; in the documentation - thus a column instead of a row vector.

1 year ago | 0

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Answered
Using fprintf in a for loop to display the output as a set of coordinate points
syms x y real y=x*(4-x)^3;dy=diff(y); x_roots=solve(dy,x); y_x_roots=subs(y,x_roots); for j=1 disp('The critical point(...

1 year ago | 0

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

1 year ago | 0

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Answered
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...

1 year ago | 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...

1 year ago | 0

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Answered
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...

1 year ago | 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...

1 year ago | 1

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Answered
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,...

1 year ago | 2

Answered
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...

1 year ago | 0

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Answered
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...

1 year ago | 1

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Answered
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...

1 year ago | 0

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Answered
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 ...

1 year ago | 1

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Answered
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...

1 year ago | 0

Answered
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(...

1 year ago | 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...

1 year ago | 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 %%%%%%%%%%%%%%%%...

1 year ago | 1

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Answered
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 ...

1 year ago | 0

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Answered
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...

1 year ago | 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...

1 year ago | 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...

1 year ago | 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...

1 year ago | 2

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Answered
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))]

1 year ago | 0

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