Fix OOM when running very large MIP instances (#658)

Reduced the maximum size of the diving queue to avoid Out-Of-Memory errors in very large instances.

Authors:
  - Nicolas L. Guidotti (https://github.com/nguidotti)

Approvers:
  - Rajesh Gandham (https://github.com/rg20)

URL: #658

Author: nguidotti

cpp/src/dual_simplex/diving_queue.hpp

@@ -31,13 +31,13 @@ struct diving_root_t {
 };
 
 // A min-heap for storing the starting nodes for the dives.
-// This has a maximum size of INT16_MAX, such that the container
+// This has a maximum size of 1024, such that the container
 // will discard the least promising node if the queue is full.
 template <typename i_t, typename f_t>
 class diving_queue_t {
  private:
   std::vector<diving_root_t<i_t, f_t>> buffer;
-  static constexpr i_t max_size_ = INT16_MAX;
+  static constexpr i_t max_size_ = 1024;
 
  public:
   diving_queue_t() { buffer.reserve(max_size_); }