--- MITgcm_contrib/mlosch/interp_llc/mdsiocompact.m	2007/05/03 21:07:21	1.1
+++ MITgcm_contrib/mlosch/interp_llc/mdsiocompact.m	2007/05/04 14:53:00	1.2
@@ -1,28 +1,68 @@
-function b=mdsiocompact(a);
-  % hack to convert to mdsio compact format
+function b=mdsiocompact(a,flag);
+  % hack to convert to and from mdsio compact format
   
-  [nx,ny,nz,nt]=size(a);
-  if nx/4~=round(nx/4);
-    error('not a llc field');
+  if nargin < 2
+    flag = 1;
   end
+  if flag
+    % convert from "nice" to compact format
+    [nx,ny,nz,nt]=size(a);
+    if nx/4~=round(nx/4);
+      error('not a llc field');
+    end
+
+    n4=nx/4;
+    m=(ny-n4)/n4;
+    m4=m*n4;
+    for kt = 1:nt
+      for kz = 1:nz
+	for k=1:4
+	  sides{k} = a([1:n4]+(k-1)*n4,1:m4,kz,kt);
+	end
+	cap = a([1:n4]+1*n4,m4+1:end,kz,kt);
+	% reformat
+	btmp = [sides{1} ...
+		sides{2} ...
+		cap ...
+		reshape(rot90(sides{3},1),[n4 m4]) ...
+		reshape(rot90(sides{4},1),[n4 m4]) ...
+		cap*0];
+	b(:,:,kz,kt)=btmp;
+      end
+    end
+  else
+    % convert from compact to "nice" format
+    [nx,m,nz,nt]=size(a);
+    if m/nx~=round(m/nx);
+      error('not a compact format llc field');
+    end
 
-  n4=nx/4;
-  m=(ny-n4)/n4;
-  m4=m*n4;
-  for kt = 1:nt
-    for kz = 1:nz
-      for k=1:4
-	sides{k} = a([1:n4]+(k-1)*n4,1:m4,kz,kt);
+    fac = 1;
+    ntiles = m/nx;
+    if mod(ntiles,2); % odd number of tiles
+      tilesPerFace = (ntiles-1)/4;
+    else
+      tilesPerFace = (ntiles-2)/4;
+    end
+    n4=tilesPerFace*nx;
+    for kt = 1:nt
+      for kz = 1:nz
+	for k=1:4
+	  jj = [1:n4]+(k-1)*n4;
+	  if k>2; jj = jj + nx; end
+	  sides{k} = a(:,jj,kz,kt);
+	end
+	cap = rot90(a(:,[1:nx]+2*n4,kz,kt),1);
+	% reformat
+	btmp = [sides{1}; ...
+		sides{2}; ...
+		rot90(reshape(sides{3}(:),[n4 nx]),-1); ...
+		rot90(reshape(sides{4}(:),[n4 nx]),-1) ];
+	b(:,:,kz,kt)=[btmp ...
+		      [cap; rot90(cap,-1)*abs(fac); ...
+		       rot90(cap,-2)*abs(fac); ...
+		       rot90(cap,-3)*abs(fac)]];
       end
-      cap = a([1:n4]+1*n4,m4+1:end,kz,kt);
-      % reformat
-      btmp = [sides{1} ...
-	      sides{2} ...
-	      cap ...
-	      reshape(rot90(sides{3},1),[n4 m4]) ...
-	      reshape(rot90(sides{4},1),[n4 m4]) ...
-	      cap*0];
-      b(:,:,kz,kt)=btmp;
     end
   end