 <p>There's a bug in your calculation: For <code>1000</code> activities and <code>200</code> resources, you don't have <code>200*1000</code> possible allocations but <code>200^1000</code> possible allocations (so more than <code>10^2000</code> possible allocations). Are you sure your optimization engine scales that much?</p> <p>Have you looked into doing resource allocation with <a href="http://docs.jboss.org/drools/release/5.5.0.Final/drools-planner-docs/html_single/index.html" rel="nofollow">Drools Planner</a> instead? Drools Planner can handle such allocation sizes and much bigger too. It searches for the best solution (and scales out well) and it uses Drools to calculate the score (= negative of the number of forbidden allocations) for each solution it evaluates.</p>