--- a/+blockmatrix/toMatrix.m	Fri Nov 03 10:43:27 2017 +0100
+++ b/+blockmatrix/toMatrix.m	Fri Nov 03 10:53:15 2017 +0100
@@ -12,16 +12,12 @@
 
     A = sparse(N,M);
 
-    n_ind = [0 cumsum(n)];
-    m_ind = [0 cumsum(m)];
-
     for i = 1:size(bm,1)
         for j = 1:size(bm,2)
             if isempty(bm{i,j})
-                continue
+                bm{i,j} = sparse(n(i),m(j));
             end
-            % TODO: If this ever fails for large matrices. Try cell2mat instead.
-            A(n_ind(i)+1:n_ind(i+1),m_ind(j)+1:m_ind(j+1)) = bm{i,j};
         end
     end
+    A = cell2mat(bm);
 end