copied the templates

generate_mesh/generate_rectangle_subdomains.m

@@ -0,0 +1,59 @@
+function [ g ] = generate_rectangle_subdomains( sx, sy )
+%Generates the geometrical description of rectangle [0,sx]x[0,sy] 
+% into sx x sy subdomains
+% 
+%% geometric description of domain,
+%  see "Decomposed Geometry Data Structure"
+%  https://de.mathworks.com/help/pde/ug/create-geometry-at-the-command-line.html#bulfvw4-1
+
+
+nsubs  = sx*sy;
+nedges = (sx)*(sy+1)+(sx+1)*sy;
+g = zeros(nedges,7);
+g(:,1) = 2;               % all edges are straight lines
+
+e = 1;                    % edge index
+
+% first the edges in x direction
+for y=0:sy
+    for x=1:sx
+        g(e,2) = x-1;             % v_1x
+        g(e,3) = x;               % v_2x
+        g(e,4) = y;               % v_1y
+        g(e,5) = y;               % v_2y
+        g(e,6) = x + y*sx;        % subdomain_left
+        g(e,7) = x + (y-1)*sx;    % subdomain_right
+        e = e+1;
+    end
+end
+
+% second the edges in y direction
+for y=1:sy
+    xsub = 0;
+    for x=0:sx
+        g(e,2) = x;               % v_1x
+        g(e,3) = x;               % v_2x
+        g(e,4) = y-1;             % v_1y
+        g(e,5) = y;               % v_2y
+        g(e,6) = xsub;
+        xsub = x + 1 + (y-1)*sx;
+        g(e,7) = xsub;
+        e = e+1;
+    end
+    g(e-1,7) = 0;
+end
+
+% set all subdomain indices (left/right) with nsubs<0 or nd>nsubs to 0.
+idx = (g(:,6)<0) | (nsubs<g(:,6));
+g(idx,6) = 0;
+idx = (g(:,7)<0) | (nsubs<g(:,7));
+g(idx,7) = 0;
+
+g=g.';        % Dimensions!
+
+%%
+% pdegplot(g,'EdgeLabels','on','FaceLabels','on')
+% [p,e,t] = initmesh(g,'hmax',0.1);
+% pdemesh(p,e,t)
+
+