How run the code including wiener process function

Question

salim 2024-12-14

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2172110-how-run-the-code-including-wiener-process-function

评论： Cris LaPierre 2024-12-16

I understand the code, but I'm not sure what the mistake is or why the Wiener function is causing a problem for me. Did I define something incorrectly? When I remove the Wiener term, the code works, but it must be included.

clc;
clear;
% Parameters
n = 1;
A = 1;                % Amplitude
B = 1;                % Width parameter of soliton
v = 1;                % Velocity of soliton
alpha = 1;            % Nonlinearity parameter
beta = 0.1;           % Dispersion parameter
gamma = 0.05;         % Noise intensity for multiplicative noise
% Grid for xi and time
xi = linspace(-20, 20, 2000);   % Spatial range in transformed coordinates
t = linspace(0, 20, 1000);       % Time range
dt = t(2) - t(1);              % Time step
% Define initial soliton profile (deterministic solution)
u_deterministic = abs(((tanh(0.192e3 ./ 0.35e2 .* t' + xi) - 0.1e1) .^ (0.1e1 ./ 0.4e1)) .* exp(i * (-0.3e1 .* xi - 0.8e1 * t' + (3 .* w(t) ))));
Unrecognized function or variable 'w'.
% Ensure u_deterministic has the correct dimensions (time x space)
if size(u_deterministic, 1) ~= length(t) || size(u_deterministic, 2) ~= length(xi)
    error('Mismatch in dimensions of u_deterministic. Check calculations.');
end
% Initialize storage for the stochastic solution
u_stochastic = zeros(length(t), length(xi));
% Generate Wiener process (increments) for time
W = cumsum(sqrt(dt) * randn(size(t))); % Wiener process for each time step
W = gamma * W; % Scale Wiener process by gamma
% Time evolution
for n = 1:length(t)
    % Apply the Wiener noise factor at time step n
    noise_factor = 1 + W(n);
    % Update solution with multiplicative noise
    u_stochastic(n, :) = u_deterministic(n, :) * noise_factor;
end
% Plot the 3D surface of the stochastic Kudryashov soliton
figure;
surf(xi, t, u_stochastic, 'EdgeColor', 'none');
xlabel('Transformed Space (\xi)');
ylabel('Time (t)');
zlabel('Amplitude (u)');
title('Stochastic Kudryashov Soliton Solution with Multiplicative Noise (Wiener Process)');
colormap jet;
colorbar;

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Answer 1

Cris LaPierre 2024-12-14

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2172110-how-run-the-code-including-wiener-process-function#answer_1555736

在 MATLAB Online 中打开

You use a function - w(t) - that you do not define in your code. At least that is the error I get in this line:

u_deterministic = abs(((tanh(0.192e3 ./ 0.35e2 .* t' + xi) - 0.1e1) .^ (0.1e1 ./ 0.4e1)) .* exp(i * (-0.3e1 .* xi - 0.8e1 * t' + (3 .* w(t) ))));

Assuming that is the wiener term you are referring to, what is it? It needs to be defined, too.

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Cris LaPierre 2024-12-15

在 MATLAB Online 中打开

You have already written code for the Wiener process. Can't you just move it up to before you define u_deterministic and then use W' instead of w(t) in your expression?

% Parameters

n = 1;

A = 1; % Amplitude

B = 1; % Width parameter of soliton

v = 1; % Velocity of soliton

alpha = 1; % Nonlinearity parameter

beta = 0.1; % Dispersion parameter

gamma = 0.05; % Noise intensity for multiplicative noise

% Grid for xi and time

xi = linspace(-20, 20, 2000); % Spatial range in transformed coordinates

t = linspace(0, 20, 1000); % Time range

dt = t(2) - t(1); % Time step

% Generate Wiener process (increments) for time

W = cumsum(sqrt(dt) * randn(size(t))); % Wiener process for each time step

W = gamma * W; % Scale Wiener process by gamma

% Define initial soliton profile (deterministic solution)

u_deterministic = abs(((tanh(0.192e3 ./ 0.35e2 .* t' + xi) - 0.1e1) .^ (0.1e1 ./ 0.4e1)) .* exp(i * (-0.3e1 .* xi - 0.8e1 * t' + (3 .* W' ))));

% Ensure u_deterministic has the correct dimensions (time x space)

if size(u_deterministic, 1) ~= length(t) || size(u_deterministic, 2) ~= length(xi)

error('Mismatch in dimensions of u_deterministic. Check calculations.');

end

% Initialize storage for the stochastic solution

u_stochastic = zeros(length(t), length(xi));

% Time evolution

for n = 1:length(t)

% Apply the Wiener noise factor at time step n

noise_factor = 1 + W(n);

% Update solution with multiplicative noise

u_stochastic(n, :) = u_deterministic(n, :) * noise_factor;

end

% Plot the 3D surface of the stochastic Kudryashov soliton

figure;

surf(xi, t, u_stochastic, 'EdgeColor', 'none');

xlabel('Transformed Space (\xi)');

ylabel('Time (t)');

zlabel('Amplitude (u)');

title('Stochastic Kudryashov Soliton Solution with Multiplicative Noise (Wiener Process)');

colormap jet;

colorbar;

salim 2024-12-15

编辑：salim 2024-12-15

@Cris LaPierre in begin i run don't have issue but now he give me erro which is

Warning: Error updating AxesLayoutManager.

Limits are too large.

Cris LaPierre 2024-12-16

Perhaps this post is helpful: https://www.mathworks.com/matlabcentral/answers/457580-limits-are-too-large

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How run the code including wiener process function

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How run the code including wiener process function

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