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function [newmsk] = findocean( oldmsk, nstartpts, periodic ); |
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|
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[nx ny]=size(oldmsk); |
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if periodic |
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xp=[2:nx 1]; |
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xm=[nx 1:nx-1]; |
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yp=[2:ny ny]; |
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ym=[1 1:ny-1]; |
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else |
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xp=[2:nx nx]; |
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xm=[1 1:nx-1]; |
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yp=[2:ny ny]; |
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ym=[1 1:ny-1]; |
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end |
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|
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msk=0*oldmsk; |
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i=0; |
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npts=nstartpts; |
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for k=1:floor(ny/npts):ny; |
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for j=1:floor(nx/npts):nx; |
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if oldmsk(j,k)==1 |
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i=i+1; |
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msk(j,k)=i; |
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end |
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end; |
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end; |
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|
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nmsk=i; |
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|
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nnz=size(find(msk==0),1); |
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nnzo=nnz+1; |
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nnzoo=nnzo+1; |
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|
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iter=0; |
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while nnz ~= nnzoo & iter < max(nx,ny)/npts |
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|
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nnzoo=nnzo; |
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nnzo=nnz; |
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|
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iter=iter+1; |
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disp( sprintf('Findocean: iter=%i, num. points in ocean=%i',iter,nnz) ); |
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pcol(sq(msk)'); drawnow; |
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% Loop over all masks values |
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k=1; |
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while k<=nmsk |
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|
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% Procreate right |
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ii=find(msk(xm,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(xm,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(xm,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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% Procreate up |
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ii=find(msk(:,ym)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(:,ym)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(:,ym)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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% Procreate left |
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ii=find(msk(xp,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(xp,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(xp,:)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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% Procreate down |
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ii=find(msk(:,yp)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(:,yp)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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ii=find(msk(:,yp)==k & msk==0 & oldmsk==1); |
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msk(ii)=k; |
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|
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for j=1:nmsk; |
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if k~=j |
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% Join left |
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ii=find(msk(xm,:)==j & msk==k); |
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if ~isempty(ii) |
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msk(find(msk==j))=k; |
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end |
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% Join down |
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ii=find(msk(:,ym)==j & msk==k); |
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if ~isempty(ii) |
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msk(find(msk==j))=k; |
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end |
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end |
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end |
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|
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k=k+1; |
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end |
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|
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nnz=size(find(msk==0),1); |
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end % while |
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|
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% Find largest patch |
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for k=1:nmsk; |
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np(k)=prod(size(find(msk==k))); |
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end |
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[NP,I]=sort(np); |
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|
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disp('Number of points in each region:') |
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disp( sprintf('%7i',NP') ); |
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|
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newmsk=0*msk; |
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newmsk( find(msk==I(end)) )=1; |
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if NP(end-1) > NP(end)/4 |
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newmsk( find(msk==I(end-1)) )=1; |
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end |