Revert "Changed the random number generator in packer to deterministic vtr::irand"

This reverts commit 53cd616.

Author: haydar-c

vpr/src/pack/greedy_candidate_selector.cpp

@@ -17,7 +17,6 @@
 #include "vpr_context.h"
 #include "vpr_types.h"
 #include "vtr_assert.h"
-#include "vtr_random.h"
 
 /*
  * @brief Get gain of packing molecule into current cluster.
@@ -519,8 +518,7 @@ t_pack_molecule* GreedyCandidateSelector::get_next_candidate_for_cluster(
                                 LegalizationClusterId cluster_id,
                                 const ClusterLegalizer& cluster_legalizer,
                                 const Prepacker& prepacker,
-                                AttractionInfo& attraction_groups,
-                                vtr::RngContainer& rng) {
+                                AttractionInfo& attraction_groups) {
     /* Finds the block with the greatest gain that satisfies the
      * input, clock and capacity constraints of a cluster that are
      * passed in.  If no suitable block is found it returns nullptr.
@@ -599,8 +597,7 @@ t_pack_molecule* GreedyCandidateSelector::get_next_candidate_for_cluster(
                                                             cluster_id,
                                                             prepacker,
                                                             cluster_legalizer,
-                                                            attraction_groups,
-                                                            rng);
+                                                            attraction_groups);
     }
     /* Grab highest gain molecule */
     // If this was a vector, this would just be a pop_back.
@@ -729,8 +726,7 @@ void GreedyCandidateSelector::add_cluster_molecule_candidates_by_attraction_grou
                                             LegalizationClusterId legalization_cluster_id,
                                             const Prepacker& prepacker,
                                             const ClusterLegalizer& cluster_legalizer,
-                                            AttractionInfo& attraction_groups,
-                                            vtr::RngContainer& rng) {
+                                            AttractionInfo& attraction_groups) {
     auto cluster_type = cluster_legalizer.get_cluster_type(legalization_cluster_id);
 
     /*
@@ -783,10 +779,17 @@ void GreedyCandidateSelector::add_cluster_molecule_candidates_by_attraction_grou
         return;
     }
 
+    int min = 0;
     int max = num_available_atoms - 1;
 
     for (int j = 0; j < attraction_group_num_atoms_threshold_; j++) {
-        int selected_atom = rng.irand(max);
+        // FIXME: This is a non-deterministic random number generator and it is
+        //        overkill to what this needs to be. Should use vtr::irand which
+        //        would be faster.
+        std::random_device rd;
+        std::mt19937 gen(rd());
+        std::uniform_int_distribution<> distr(min, max);
+        int selected_atom = distr(gen);
 
         AtomBlockId blk_id = available_atoms[selected_atom];
 

vpr/src/pack/greedy_candidate_selector.h

@@ -16,7 +16,6 @@
 #include "cluster_legalizer.h"
 #include "physical_types.h"
 #include "vtr_vector.h"
-#include "vtr_random.h"
 
 // Forward declarations
 class AtomNetlist;
@@ -302,8 +301,7 @@ class GreedyCandidateSelector {
                                     LegalizationClusterId cluster_id,
                                     const ClusterLegalizer& cluster_legalizer,
                                     const Prepacker& prepacker,
-                                    AttractionInfo& attraction_groups,
-                                    vtr::RngContainer& rng);
+                                    AttractionInfo& attraction_groups);
 
     /**
      * @brief Finalize the creation of a cluster.
@@ -456,8 +454,7 @@ class GreedyCandidateSelector {
                                 LegalizationClusterId legalization_cluster_id,
                                 const Prepacker& prepacker,
                                 const ClusterLegalizer& cluster_legalizer,
-                                AttractionInfo& attraction_groups,
-                                vtr::RngContainer& rng);
+                                AttractionInfo& attraction_groups);
 
     /**
      * @brief Finds a molecule to propose which is unrelated but may be good to

vpr/src/pack/greedy_clusterer.cpp

@@ -55,7 +55,6 @@
 #include "vpr_context.h"
 #include "vtr_math.h"
 #include "vtr_vector.h"
-#include "vtr_random.h"
 
 namespace {
 
@@ -161,8 +160,6 @@ GreedyClusterer::do_clustering(ClusterLegalizer& cluster_legalizer,
 
     print_pack_status_header();
 
-    vtr::RngContainer rng(0);
-    
     // Continue clustering as long as a valid seed is returned from the seed
     // selector.
     while (seed_mol != nullptr) {
@@ -186,8 +183,7 @@ GreedyClusterer::do_clustering(ClusterLegalizer& cluster_legalizer,
                                         balance_block_type_utilization,
                                         attraction_groups,
                                         num_used_type_instances,
-                                        mutable_device_ctx,
-                                        rng);
+                                        mutable_device_ctx);
 
         if (!new_cluster_id.is_valid()) {
             // If the previous strategy failed, try to grow the cluster again,
@@ -201,8 +197,7 @@ GreedyClusterer::do_clustering(ClusterLegalizer& cluster_legalizer,
                                        balance_block_type_utilization,
                                        attraction_groups,
                                        num_used_type_instances,
-                                       mutable_device_ctx,
-                                       rng);
+                                       mutable_device_ctx);
         }
 
         // Ensure that the seed was packed successfully.
@@ -244,8 +239,7 @@ LegalizationClusterId GreedyClusterer::try_grow_cluster(
                                        bool balance_block_type_utilization,
                                        AttractionInfo& attraction_groups,
                                        std::map<t_logical_block_type_ptr, size_t>& num_used_type_instances,
-                                       DeviceContext& mutable_device_ctx,
-                                       vtr::RngContainer& rng) {
+                                       DeviceContext& mutable_device_ctx) {
 
     // Check to ensure that this molecule is unclustered.
     VTR_ASSERT(!cluster_legalizer.is_mol_clustered(seed_mol));
@@ -273,8 +267,7 @@ LegalizationClusterId GreedyClusterer::try_grow_cluster(
                                                 legalization_cluster_id,
                                                 cluster_legalizer,
                                                 prepacker,
-                                                attraction_groups,
-                                                rng);
+                                                attraction_groups);
 
     /*
      * When attraction groups are created, the purpose is to pack more densely by adding more molecules
@@ -323,8 +316,7 @@ LegalizationClusterId GreedyClusterer::try_grow_cluster(
                                                 legalization_cluster_id,
                                                 cluster_legalizer,
                                                 prepacker,
-                                                attraction_groups,
-                                                rng);
+                                                attraction_groups);
 
         // If the next candidate molecule is the same as the previous
         // candidate molecule, increment the number of repeated

vpr/src/pack/greedy_clusterer.h

@@ -13,7 +13,6 @@
 #include <vector>
 #include "cluster_legalizer.h"
 #include "physical_types.h"
-#include "vtr_random.h"
 
 // Forward declarations
 class AtomNetId;
@@ -157,8 +156,7 @@ class GreedyClusterer {
                                            bool balance_block_type_utilization,
                                            AttractionInfo& attraction_groups,
                                            std::map<t_logical_block_type_ptr, size_t>& num_used_type_instances,
-                                           DeviceContext& mutable_device_ctx,
-                                           vtr::RngContainer& rng);
+                                           DeviceContext& mutable_device_ctx);
 
     /**
      * @brief Given a seed molecule, starts a new cluster by trying to find a