Réponse apportée
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...

environ un an il y a | 0

| A accepté

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

| A accepté

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

environ un an il y a | 0

| A accepté

Réponse apportée
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(...

environ un an il y a | 0

| A accepté

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

environ un an il y a | 0

| A accepté

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

| A accepté

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 1

| A accepté

Réponse apportée
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,...

environ un an il y a | 2

Réponse apportée
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...

environ un an il y a | 0

| A accepté

Réponse apportée
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...

environ un an il y a | 1

| A accepté

Réponse apportée
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...

environ un an il y a | 0

| A accepté

Réponse apportée
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 ...

environ un an il y a | 1

| A accepté

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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(...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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 %%%%%%%%%%%%%%%%...

environ un an il y a | 1

| A accepté

Réponse apportée
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 ...

environ un an il y a | 0

| A accepté

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 0

Réponse apportée
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...

environ un an il y a | 2

| A accepté

Réponse apportée
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))]

environ un an il y a | 0

| A accepté

Réponse apportée
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,...

environ un an il y a | 0

Réponse apportée
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/...

environ un an il y a | 0

| A accepté

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

environ un an il y a | 0

| A accepté

Réponse apportée
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,...

environ un an il y a | 0

| A accepté