added loopedit (optionally called in mctd_04 for downcast)

 Committer: PStar User Account <pstar@192.168.122.1>

 On branch dy113
 Changes to be committed:

	new file:   source/unfinished/m_loopedit.m

source/unfinished/m_loopedit.m

+function pe = m_loopeditp(p, ptol);
+% function pe = m_loopeditp(p, ptol);
+%
+% edit out pressures that are not > previous max press - ptol
+% 
+% only suitable for downcast data
+%
+% once you've used this you can apply same NaNs to other fields
+%
+% see mctd_04
+
+if size(p,1) == 1
+    trp = 1;
+    p = p';
+else
+    trp = 0;
+end
+
+np = length(p);
+pm = zeros(1,np); %this will contain max pressure above (before) each point
+
+%separate into chunks otherwise matrix is too big
+nm = 30000; ns = floor(np/nm); nr = np-nm*ns;
+
+m = repmat([1:nm]',1,nm)<repmat([1:nm],nm,1); %diagonal mask
+
+%first chunk
+pm(1:nr) = max(repmat(p(1:nr),1,nr).*m(1:nr,1:nr)); %max p at/before each level
+
+%rest of them
+for no = 1:ns
+    ii = [nr+1:nr+nm]+(no-1)*nm;
+    pm(ii) = max(repmat(p(ii),1,nm).*m); %max p in this chunk at/before each level
+    pm(ii) = max(pm(ii), max(pm(1:ii(1)-1))); %and test against earlier chunks
+end
+
+ii = find(p'<=pm-ptol);
+pe = p; pe(ii) = NaN;
+
+if trp
+    pe = pe';
+end