Select triangles using relative tolerance criterion
bt = pdeadgsc(p,t,c,a,f,u,errf,tol)
bt = pdeadgsc(p,t,c,a,f,u,errf,tol) returns indices of triangles to be refined in bt. Used from adaptmesh to select the triangles to be further refined. The geometry of the PDE problem is given by the mesh data p and t. For more details, see Mesh Data.
u is the current solution, given as a column vector. For details, see assempde.
Triangles are selected using the criterion errf>tol*scale, where scale is calculated as follows:
Let cmax, amax, fmax, and umax be the maximum of c, a, f, and u, respectively. Let l be the side of the smallest axis-aligned square that contains the geometry.
Then scale = max(fmax*l^2,amax*umax*l^2,cmax*umax). The scaling makes the tol parameter independent of the scaling of the equation and the geometry.