source: issm/trunk/src/m/classes/public/BasinConstrain.m@ 1234

function md=BasinConstrain(md,domain);
%BASINCONSTRAIN constrain basin, using a constraint domain outline, to dirichlet boundary conditions.
%
% usage: md=BasinConstrain(md,constraindomain)
%          
%            where constraindomain is an Argus domain outline file enclosing the geographical area of interest.
%
% See also: N/A

%prepare barycentre positions.
xelem=md.x(md.elements)*[1;1;1]/3;
yelem=md.y(md.elements)*[1;1;1]/3;

%now, flag grids and elements outside the domain outline.
[gridondomain elementondomain]=ContourToMesh(md.elements,md.x,md.y,expread(domain,1),'element and node',2);
gridnotondomain=find(~gridondomain);
elementnotondomain=find(~elementondomain);

%all elements outside the constraint domain are equivalent to water. all grids outside are spc'd.
md.gridondirichlet_diag(gridnotondomain)=1;
md.dirichletvalues_diag(gridnotondomain,1)=md.vx_obs(gridnotondomain);
md.dirichletvalues_diag(gridnotondomain,2)=md.vy_obs(gridnotondomain);
md.elementonwater(elementnotondomain)=1;


%now, make sure all elements on water have grids that are spc'd, otherwise, we'll get a singular problem.
pos=find(md.elementonwater);
grids=unique(md.elements(pos,:));

md.gridondirichlet_diag(grids)=1;
md.dirichletvalues_diag(grids,1)=md.vx_obs(grids);
md.dirichletvalues_diag(grids,2)=md.vy_obs(grids);