Partial Differential Equation Toolbox |

pdeadgsc

Select triangles using a relative tolerance criterion

Syntax

-     bt=pdeadgsc(p,t,c,a,f,u,errf,tol)

Description

`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 the entry on `initmesh`.

`c, a, and f` are PDE coefficients. For details, see `assempde`.

`u` is the current solution, given as a column vector. For details, see `assempde`.

`errf` is the error indicator, as calculated by `pdejmps`.

`tol` is a tolerance parameter.

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.

See Also

`adaptmesh`, `pdejmps`

| parabolic |  | pdeadworst |