Cleaned up some cover code

modules/global/knapsack_cover_lift_balas.m

@@ -1,16 +1,10 @@
 function q = knapsack_cover_lift_balas(a,Cset)
 Nset = setdiff(1:length(a),Cset);
 S = cumsum(sort(a(Cset),'descend'));
+S = [0 S(:)'];
 q = zeros(1,length(a));
 q(Cset)=1;
 for k = Nset
-    j = max(find(a(k) >= S));
-    if ~isempty(j)
-        j2 = min(find(a(k) < S));
-        if isempty(j2)
-            'Weird, a variable should be 0'
-        else
-            q(k)=0;
-        end
-    end
+    lambda = max(find(a(k) >= S))-1;
+    q(k) = lambda;
 end

modules/global/knapsack_create_cover_cut.m

@@ -17,7 +17,7 @@
 if ~all(a)
     nz = find(a);
     a_ = a(nz); 
-    cut_ = knapsack_create_cover_cut(a_,b,x(nz),alg);
+    cut_ = knapsack_create_cover_cut(a_,b,x(nz),alg);  
     if ~isempty(cut_)
         cut = spalloc(1,length(a)+1,0);
         cut(1) = cut_(1);
@@ -65,11 +65,20 @@
 
 % Apply Balas lifting
 q = knapsack_cover_lift_balas(a,loc(1:C));
+%q = extendcover(q,a);
 % Return row where row*[1;x] hopefully is violated
 cut = spalloc(1,length(a)+1,0);
 cut(1) = C-1;
 cut(2:end)=-q;
 
+function q = extendcover(q,a);
+if any(q)
+    a_C_max = max(a(find(q)));
+    s = find(a >= a_C_max);
+    q(s) = 1;
+end
+
+