comparison toolboxes/FullBNT-1.0.7/KPMtools/plotgauss2d_old.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function h=plotgauss2d_old(mu, Sigma, plot_cross)
+% PLOTGAUSS2D Plot a 2D Gaussian as an ellipse with optional cross hairs
+% h=plotgauss2(mu, Sigma)
+% 
+% h=plotgauss2(mu, Sigma, 1) also plots the major and minor axes
+%
+% Example
+% clf; S=[2 1; 1 2]; plotgauss2d([0;0], S, 1); axis equal
+
+if nargin < 3, plot_cross = 0; end
+[V,D]=eig(Sigma);
+lam1 = D(1,1);
+lam2 = D(2,2);
+v1 = V(:,1);
+v2 = V(:,2);
+%assert(approxeq(v1' * v2, 0))
+if v1(1)==0
+  theta = 0; % horizontal
+else
+  theta = atan(v1(2)/v1(1));
+end
+a = sqrt(lam1);
+b = sqrt(lam2);
+h=plot_ellipse(mu(1), mu(2), theta, a,b);
+
+if plot_cross
+  mu = mu(:);
+  held = ishold;
+  hold on
+  minor1 = mu-a*v1; minor2 = mu+a*v1;
+  hminor = line([minor1(1) minor2(1)], [minor1(2) minor2(2)]);
+  
+  major1 = mu-b*v2; major2 = mu+b*v2;
+  hmajor = line([major1(1) major2(1)], [major1(2) major2(2)]);
+  %set(hmajor,'color','r')
+  if ~held
+    hold off
+  end
+end
+