www.gusucode.com > symbolic 源码程序 matlab案例代码 > symbolic/FindElectricChargeDensityFromElectricFieldExample.m
%% Find Electric Charge Density from Electric Field %% 1 % Copyright 2015 The MathWorks, Inc. syms x y ep0 E = [x^2 y^2]; rho = divergence(E,[x y])*ep0 %% 2 rho = subs(rho,ep0,1); v = -2:0.1:2; [xPlot,yPlot] = meshgrid(v); Ex = subs(E(1),x,xPlot); Ey = subs(E(2),y,yPlot); rhoPlot = double(subs(rho,{x,y},{xPlot,yPlot})); %% 3 quiver(xPlot,yPlot,Ex,Ey) hold on contour(xPlot,yPlot,rhoPlot,'ShowText','on') title('Contour Plot of Charge Density Over Electric Field') xlabel('x') ylabel('y')