distance_along_BC

 Calculates the distance from coast along the open boundary nodes

 Mobj=distance_along_BC(Mobj,BCnodes,conf)

 DESCRIPTION:
    Calculates distance from coast along open boundary nodes and
    store them in a matlab mesh object

 INPUT 
   Mobj                   = Mesh object structure variable
   BCnodes                = indices of nodes located at the boundary
   conf                   = configuration structure variable with the
   directory where the HJB_Solver_Package is installed

 OUTPUT:
    Mobj = matlab structure containing distance data

 EXAMPLE USAGE
     Mobj=distance_along_BC(Mobj,BCnodes,conf)
 This function needs the HJB_solver package by Shawn Walker and can be downloaded from Matlab central 
 http://www.mathworks.com/matlabcentral/fileexchange/24827-hamilton-jacobi-solver-on-unstructured-triangular-grids

0001 function Mobj=distance_along_BC(Mobj,BCnodes,conf)
0002 % Calculates the distance from coast along the open boundary nodes
0003 %
0004 % Mobj=distance_along_BC(Mobj,BCnodes,conf)
0005 %
0006 % DESCRIPTION:
0007 %    Calculates distance from coast along open boundary nodes and
0008 %    store them in a matlab mesh object
0009 %
0010 % INPUT
0011 %   Mobj                   = Mesh object structure variable
0012 %   BCnodes                = indices of nodes located at the boundary
0013 %   conf                   = configuration structure variable with the
0014 %   directory where the HJB_Solver_Package is installed
0015 %
0016 % OUTPUT:
0017 %    Mobj = matlab structure containing distance data
0018 %
0019 % EXAMPLE USAGE
0020 %     Mobj=distance_along_BC(Mobj,BCnodes,conf)
0021 % This function needs the HJB_solver package by Shawn Walker and can be downloaded from Matlab central
0022 % http://www.mathworks.com/matlabcentral/fileexchange/24827-hamilton-jacobi-solver-on-unstructured-triangular-grids
0023 
0024 % Author(s):
0025 %    Ricardo Torres  (Plymouth Marine Laboratory)
0026 %
0027 % Revision history
0028 %
0029 %   2015-11-20 First version
0030 %
0031 %==============================================================================
0032 
0033 dump = dbstack;
0034 subname = dump.name;
0035 clear dump
0036 global ftbverbose;
0037 if ftbverbose
0038     fprintf('\nbegin : %s \n', subname)
0039 end
0040 CD=pwd;
0041 % setup HPJ solver to calculate the distance function for the SMS mesh
0042  [~,~,~,bnd] = connectivity([Mobj.x,Mobj.y],Mobj.tri);
0043 % remove nodestring from coast.
0044 % BCnodes=[Mobj.read_obc_nodes{:}];
0045 coast_ind=(BCnodes);
0046 
0047 
0048  % % calculate distance function
0049 myParam.Max_Tri_per_Star = 20;
0050 myParam.NumGaussSeidel = 40;
0051 myParam.INF_VAL = 1000000;
0052 myParam.TOL = 1e-12;
0053 % in this case, we will assume the standard Euclidean metric
0054 myMetric = [];
0055 myTM.Vtx=[Mobj.x(:),Mobj.y(:)];
0056 myTM.DoFmap=[Mobj.tri];
0057 myTM.NegMask=false(size(bnd));
0058 myBdy.Nodes=coast_ind(:);
0059 myBdy.Data=zeros(size(myBdy.Nodes));
0060 %
0061 cd (conf.HJB_Solver_Package)
0062 %
0063 %
0064 SEmex  = SolveEikonalmex(myTM,myBdy,myParam,myMetric);
0065 tic
0066 Mobj.distOB  = SEmex.Compute_Soln;
0067 cd(CD)
0068 if ftbverbose
0069     fprintf('end   : %s \n', subname)
0070 end
0071 return