From 88f1c5dbf43c07bac312f84d2b8c2a102c1d095f Mon Sep 17 00:00:00 2001
From: David Allemang <david.allemang@kitware.com>
Date: Sat, 26 Feb 2022 00:13:39 -0500
Subject: [PATCH] WIP: Oversimplify reltables

---
 tc/src/solve.cpp | 84 ++++++++++++++----------------------------------
 1 file changed, 25 insertions(+), 59 deletions(-)

diff --git a/tc/src/solve.cpp b/tc/src/solve.cpp
index 0c144f0..5cc6d28 100644
--- a/tc/src/solve.cpp
+++ b/tc/src/solve.cpp
@@ -2,68 +2,34 @@
 
 #include <algorithm>
 
-namespace tc {
-    struct RelTablesRow {
-        int *gnrs;
-        int **lst_ptrs;
+namespace {
+    using namespace tc;
 
-        RelTablesRow(int N, int *gnrs, int **lst_ptrs) : gnrs(gnrs), lst_ptrs(lst_ptrs) {
-            for (int i = 0; i < N; i++) {
-                lst_ptrs[i] = nullptr;
-            }
+    struct Row {
+        std::vector<int> gnrs;
+        std::vector<int *> lst_ptrs;
+
+        Row(int num_tables)
+            : gnrs(num_tables, 0), lst_ptrs(num_tables, nullptr) {
         }
     };
 
-    struct RelTables {
-        static const int ROW_BLOCK_SIZE = 64;
+    struct Tables {
         std::vector<Rel> rels;
-        std::vector<RelTablesRow *> rows;
-        int start = 0;
+        std::vector<Row> rows;
         int num_tables;
-        int buffer_rows = 0;
 
-        explicit RelTables(const std::vector<Rel> &rels)
+        explicit Tables(const std::vector<Rel> &rels)
             : num_tables(rels.size()), rels(rels) {
         }
 
         void add_row() {
-            if (buffer_rows == 0) {
-                int *gnrs_alloc = new int[num_tables * RelTables::ROW_BLOCK_SIZE];
-                int **lst_ptrs_alloc = new int *[num_tables * RelTables::ROW_BLOCK_SIZE];
-                for (int i = 0; i < RelTables::ROW_BLOCK_SIZE; i++) {
-                    rows.push_back(
-                        new RelTablesRow(num_tables, &gnrs_alloc[i * num_tables], &lst_ptrs_alloc[i * num_tables]));
-                }
-                buffer_rows = RelTables::ROW_BLOCK_SIZE;
-            }
-
-            buffer_rows--;
-        }
-
-        void del_rows_to(int idx) {
-            const int del_to = (idx / RelTables::ROW_BLOCK_SIZE) * RelTables::ROW_BLOCK_SIZE;
-            for (int i = start; i < del_to; i += RelTables::ROW_BLOCK_SIZE) {
-                delete[] rows[i]->gnrs;
-                delete[] rows[i]->lst_ptrs;
-                for (int j = 0; j < RelTables::ROW_BLOCK_SIZE; j++) {
-                    delete rows[i + j];
-                }
-                start += RelTables::ROW_BLOCK_SIZE;
-            }
-        }
-
-        ~RelTables() {
-            while (start < rows.size()) {
-                delete[] rows[start]->gnrs;
-                delete[] rows[start]->lst_ptrs;
-                for (int j = 0; j < RelTables::ROW_BLOCK_SIZE; j++) {
-                    delete rows[start + j];
-                }
-                start += RelTables::ROW_BLOCK_SIZE;
-            }
+            rows.emplace_back(num_tables);
         }
     };
+}
 
+namespace tc {
     Cosets Group::solve(const std::vector<int> &sub_gens) const {
         Cosets cosets(ngens);
         cosets.add_row();
@@ -72,15 +38,15 @@ namespace tc {
             return cosets;
         }
 
-        for (int g : sub_gens) {
+        for (int g: sub_gens) {
             if (g < ngens)
                 cosets.put(0, g, 0);
         }
 
-        RelTables rel_tables(rels());
+        Tables rel_tables(rels());
         std::vector<std::vector<int>> gen_map(ngens);
         int rel_idx = 0;
-        for (Rel m : rels()) {
+        for (Rel m: rels()) {
             gen_map[m.gens[0]].push_back(rel_idx);
             gen_map[m.gens[1]].push_back(rel_idx);
             rel_idx++;
@@ -88,7 +54,7 @@ namespace tc {
 
         int null_lst_ptr;
         rel_tables.add_row();
-        RelTablesRow &row = *(rel_tables.rows[0]);
+        Row &row = rel_tables.rows[0];
         for (int table_idx = 0; table_idx < rel_tables.num_tables; table_idx++) {
             Rel &ti = rel_tables.rels[table_idx];
 
@@ -108,7 +74,7 @@ namespace tc {
                 idx++;
 
             if (idx == cosets.data.size()) {
-                rel_tables.del_rows_to(idx / ngens);
+//                rel_tables.del_rows_to(idx / ngens);
                 break;
             }
 
@@ -122,9 +88,9 @@ namespace tc {
             coset = idx / ngens;
             gen = idx % ngens;
 
-            rel_tables.del_rows_to(coset);
+//            rel_tables.del_rows_to(coset);
 
-            RelTablesRow &target_row = *(rel_tables.rows[target]);
+            Row &target_row = rel_tables.rows[target];
             while (!facts.empty()) {
                 fact_idx = facts.back();
                 facts.pop_back();
@@ -138,12 +104,12 @@ namespace tc {
                 gen = fact_idx % ngens;
 
                 if (target == coset)
-                    for (int table_idx : gen_map[gen])
+                    for (int table_idx: gen_map[gen])
                         if (target_row.lst_ptrs[table_idx] == nullptr)
                             target_row.gnrs[table_idx] = -1;
 
-                RelTablesRow &coset_row = *(rel_tables.rows[coset]);
-                for (int table_idx : gen_map[gen]) {
+                Row &coset_row = rel_tables.rows[coset];
+                for (int table_idx: gen_map[gen]) {
                     if (target_row.lst_ptrs[table_idx] == nullptr) {
                         Rel &ti = rel_tables.rels[table_idx];
                         target_row.lst_ptrs[table_idx] = coset_row.lst_ptrs[table_idx];
@@ -174,7 +140,7 @@ namespace tc {
                 if (target_row.lst_ptrs[table_idx] == nullptr) {
                     if ((cosets.get(target, ti.gens[0]) != target) and
                         (cosets.get(target, ti.gens[1]) != target)) {
-                        target_row.lst_ptrs[table_idx] = new int;
+                        target_row.lst_ptrs[table_idx] = new int;  // todo slow; memory leak.
                         target_row.gnrs[table_idx] = 0;
                     } else {
                         target_row.lst_ptrs[table_idx] = &null_lst_ptr;