add methods to reset/unset build policy

src/toolkit/matl_buy_policy.cc

@@ -34,6 +34,19 @@ MatlBuyPolicy::~MatlBuyPolicy() {
     manager()->context()->UnregisterTrader(this);
 }
 
+MatlBuyPolicy& MatlBuyPolicy::ResetBehavior() {
+  throughput_ = std::numeric_limits<double>::max();
+  quantize_ = 1;
+  fill_to_ = std::numeric_limits<double>::max();
+  req_at_ = std::numeric_limits<double>::max();
+  cumulative_cap_ = -1;
+  cycle_total_inv_ = 0;
+  active_dist_ = NULL;
+  dormant_dist_ = NULL;
+  size_dist_ = NULL;
+  return *this;
+}
+
 void MatlBuyPolicy::set_manager(Agent* m) {
   if (m != NULL) {
     Trader::manager_ = m;
@@ -238,6 +251,12 @@ MatlBuyPolicy& MatlBuyPolicy::Set(std::string commod, Composition::Ptr c,
   return *this;
 }
 
+MatlBuyPolicy& MatlBuyPolicy::Unset(std::string commod){
+
+  commod_details_.erase(commod);
+  return *this;
+}
+
 void MatlBuyPolicy::Start() {
   if (manager() == NULL) {
     std::stringstream ss;

src/toolkit/matl_buy_policy.h

@@ -141,6 +141,13 @@ class MatlBuyPolicy : public Trader {
                       IntDistribution::Ptr);
   /// @}
 
+  /// Reset a material buy policy parameters that govern its behavior 
+  /// to the default state.  Preserve the Trader that manages the policy.
+  /// The primary use case of this method is when there is a desire to
+  /// change the behavior of a policy. This reset can be called prior
+  /// to calling a new `Init()` to establish the new behavior.
+  MatlBuyPolicy& ResetBehavior();
+
   /// Instructs the policy to fill its buffer with requests on the given
   /// commodity of composition c and the given preference.  This must be called
   /// at least once or the policy will do nothing.  The policy can request on an
@@ -156,6 +163,9 @@ class MatlBuyPolicy : public Trader {
   MatlBuyPolicy& Set(std::string commod, Composition::Ptr c, double pref);
   /// @}
 
+  /// Instructs the policy to stop requesting a speific commodity
+  MatlBuyPolicy& Unset(std::string commod);
+
   /// Registers this policy as a trader in the current simulation.  This
   /// function must be called for the policy to begin participating in resource
   /// exchange. Init MUST be called prior to calling this function.  Start is