我试着重做泊松方程，这样∂？∂/Φx？=2x？-0.5x+exp(X)。每次我尝试输入公式的右侧时，它都会出现语法错误，如果有任何帮助，我将非常感激。

% Solving of 1D Poisson equation
% using finite differences

% Clearing memory and figures
clear all
clf

% Define 1D numerical model
xsize=100; % Model size in horizontal direction, m
Nx=101; % Number of grid points
dx=xsize/(Nx-1); % Gridstep, m
x=0:dx:xsize; % Coordinates of grid points, m

% Defining global matrixes
L=zeros(Nx,Nx); % Koefficients in the left part
R=zeros(Nx,1); % Right parts of equations

% Composing global matrixes
% by going through all grid points
for j=1:1:Nx
    % Discriminating between BC-points and internal points
    if(j==1 || j==Nx)
        % BC-points
        L(j,j)=1; % Left part
        R(j)=0; % Right part
    else
        % Composing Poisson eq. d2T/dx2=1
        %
        % ---T(j-1)------T(j)------T(j+1)---- STENCIL
        %
        % 1/dx2*T(j-1)+(-2/dx2)*T(j)+1/dx2*T(j+1)=1
        %
        % Left part of j-equation
        L(j,j-1)=1/dx^2; % T(j-1)
        L(j,j)=-2/dx^2; % T(j)
        L(j,j+1)=1/dx^2; % T(j+1)
        % Right part
        R(j)=2x;
    end
end

% Solve the matrix
S=L\R;

% Reload solutions
T=zeros(1,Nx); % Create array for temperature, K
for j=1:1:Nx
    T(j)=S(j);
end

% Visualize results
figure(1); clf
plot(x,T,'o r') % Plotting results

我再次感谢在这件事上的任何帮助