plotfield.m

解决麦克斯韦的matlab源文件

function plotfield(mesh,vals,titstr)
% Creates an arrow plot of a vectorfield whose values are stored
% in the vals column vector
%
% mesh -> Data for 2D unstructured mesh
% vals -> column vector whose length must agree with mesh.Nv
%

if (size(vals,1) ~= 2*mesh.Nv), error('Size mismatch for argument vector'); end
if (size(vals,2) ~= 1), error('Vals must be a colun vector'); end
if (nargin < 3), titstr = 'Arrowplot of vectorfield'; end

hold on;
title(titstr);
bb = [ 0 0 0 0 ];

% Plot boundary of domain
ebd_idx  = find(mesh.ebfl(:,1) ~= 0);
for i=ebd_idx'
  ev = [mesh.vt(mesh.ep(i,1),:)' mesh.vt(mesh.ep(i,2),:)']; 
  plot(ev(1,:),ev(2,:),'k-');
  bb = [ min([ev(1,1),ev(1,2),bb(1)]),...
	 max([ev(1,1),ev(1,2),bb(2)]),...
	 min([ev(2,1),ev(2,2),bb(3)]),...
	 max([ev(2,1),ev(2,2),bb(4)]) ];
end

% Plot arrows
vx = vals(1:2:2*mesh.Nv,1);
vy = vals(2:2:2*mesh.Nv,1);
quiver(mesh.vt(:,1),mesh.vt(:,2),vx,vy,0.75,'b-');
axis(bb);
hold off;