diff --git a/brew/vecfit.m b/brew/vecfit.m
index 87b2ab0..f4840a5 100644
--- a/brew/vecfit.m
+++ b/brew/vecfit.m
@@ -22,59 +22,68 @@
 ## Author: Jens <jens@orion>
 ## Created: 2023-06-10
 
-function [P1, Pa1, D] = vecfit (Pp, mask, Pt, P0, Pa0, step)
+function [P1, na_1, D] = vecfit (Pp, ignore_mask, Pt, P0, na_0, step)
 
   [N_subst, N_elem] = size(Pp);
 
-  # Create default mask
-  if isempty(mask),
-    mask = ones(1,N_elem);
+  # Create default ignore_mask
+  if isempty(ignore_mask),
+    ignore_mask = ones(1,N_elem);
   end
 
   # A-Priory state with mask
-  P1 = P0 + sum(Pp.*Pa0.*mask);
+  P1 = P0 + sum(Pp.*na_0.*ignore_mask);
 
   # Calc distance to target
   d = (Pt-P1);
   D = norm(d);
   dn = d/D;
 
-  # Find best prototype
-  best_i = 0;
-  best_k = 10000;
-  best_dir = 1;
+  subst_list = 1:N_subst;
 
-  for i=1:N_subst,
-    p = Pp(i,:);
-    pn = p/norm(p);
+  while 1,
+    # Find best prototype
+    best_i = 0;
+    best_k = 10000;
+    best_dir = 1;
+    for i=subst_list,
+      p = Pp(i,:);
+      pn = p/norm(p);
 
-    # compare d and p
-    for vecdir=[1,-1],
-      k = norm(vecdir*pn - dn);
-      if k < best_k,
-        best_k = k;
-        best_i = i;
-        best_dir = vecdir;
+      # compare d and p
+      for vecdir=[1,-1],
+        k = norm(vecdir*pn - dn);
+        if k < best_k,
+          best_k = k;
+          best_i = i;
+          best_dir = vecdir;
+        end
       end
     end
-  end
 
-  # Calc next Pa
-  Pa1 = Pa0;
+    # Calc next Pa
+    na_1 = na_0;
 
-  # Calc P1
-  P1 = P0 + sum(Pp.*Pa0);
+    # Calc P1
+    P1 = P0 + sum(Pp.*na_0);
 
-  if best_i,
-    # Get value from best prototype
-    delta = best_dir*step;
-    dps = delta*Pp(best_i,:);
+    if best_i,
+      # Get value from best prototype
+      delta = best_dir*step;
+      dps = delta*Pp(best_i,:);
 
-    # Update point
-    P1 += dps;
-
-    # Update Point accu
-    Pa1(best_i) += delta;
-  end
+      # Check for negative n
+      accu = na_1(best_i) + delta;
+      if accu < 0,
+        subst_list(best_i) = [];
+        continue;
+      end
+      # Update point
+      P1 += dps;
 
+      # Update Point accu
+      na_1(best_i) = accu;
+      break;
+    end
+end
 endfunction