From bf491117c7d35d90c56478d05798c339e8dca0d1 Mon Sep 17 00:00:00 2001
From: Mavo <matthias.volk@rwth-aachen.de>
Date: Mon, 10 Oct 2016 17:26:45 +0200
Subject: [PATCH] Sort row only if replacement took place

Former-commit-id: 84f584d6c4dea92d8b199d34af2074e1e2163ed0
---
 src/storage/SparseMatrix.cpp | 73 ++++++++++++------------------------
 src/storage/SparseMatrix.h   |  8 +---
 2 files changed, 24 insertions(+), 57 deletions(-)

diff --git a/src/storage/SparseMatrix.cpp b/src/storage/SparseMatrix.cpp
index c43dc77d9..d38b0a838 100644
--- a/src/storage/SparseMatrix.cpp
+++ b/src/storage/SparseMatrix.cpp
@@ -22,6 +22,8 @@
 
 #include "src/utility/macros.h"
 
+#include <iterator>
+
 namespace storm {
     namespace storage {
         
@@ -267,66 +269,37 @@ namespace storm {
         }
         
         template<typename ValueType>
-        bool SparseMatrixBuilder<ValueType>::replaceColumns(std::vector<index_type> const& replacements, index_type offset) {
-            bool changed = false;
+        void SparseMatrixBuilder<ValueType>::replaceColumns(std::vector<index_type> const& replacements, index_type offset) {
             index_type maxColumn = 0;
-            for (auto& elem : columnsAndValues) {
-                if (elem.getColumn() >= offset) {
-                    elem.setColumn(replacements[elem.getColumn() - offset]);
-                    changed = true;
-                }
-                maxColumn = std::max(maxColumn, elem.getColumn());
-            }
-            STORM_LOG_ASSERT(changed || highestColumn == maxColumn, "Incorrect maximal column.");
-            highestColumn = maxColumn;
-            STORM_LOG_ASSERT(changed || lastColumn == columnsAndValues[columnsAndValues.size() - 1].getColumn(), "Incorrect last column.");
-            lastColumn = columnsAndValues[columnsAndValues.size() - 1].getColumn();
-            
-            if (changed) {
-                fixColumns();
-            }
-            return changed;
-        }
 
-        template<typename ValueType>
-        void SparseMatrixBuilder<ValueType>::fixColumns() {
-            // Sort columns per row
-            typename SparseMatrix<ValueType>::index_type endGroups;
-            typename SparseMatrix<ValueType>::index_type endRows;
-            
-            if (hasCustomRowGrouping) {
-                for (index_type group = 0; group < rowGroupIndices.get().size(); ++group) {
-                    endGroups = group < rowGroupIndices.get().size()-1 ? rowGroupIndices.get()[group+1] : rowIndications.size();
-                    for (index_type i = rowGroupIndices.get()[group]; i < endGroups; ++i) {
-                        endRows = i < rowIndications.size()-1 ? rowIndications[i+1] : columnsAndValues.size();
-                        // Sort the row
-                        std::sort(columnsAndValues.begin() + rowIndications[i], columnsAndValues.begin() + endRows,
-                                  [](MatrixEntry<index_type, value_type> const& a, MatrixEntry<index_type, value_type> const& b) {
-                                      return a.getColumn() < b.getColumn();
-                                  });
-                        // Assert no equal elements
-                        STORM_LOG_ASSERT(std::is_sorted(columnsAndValues.begin() + rowIndications[i], columnsAndValues.begin() + endRows,
-                                              [](MatrixEntry<index_type, value_type> const& a, MatrixEntry<index_type, value_type> const& b) {
-                                                  return a.getColumn() <= b.getColumn();
-                                              }), "Columns not sorted.");
+            for (index_type row = 0; row < rowIndications.size(); ++row) {
+                bool changed = false;
+                auto startRow = std::next(columnsAndValues.begin(), rowIndications[row]);
+                auto endRow = row < rowIndications.size()-1 ? std::next(columnsAndValues.begin(), rowIndications[row+1]) : columnsAndValues.end();
+                for (auto entry = startRow; entry != endRow; ++entry) {
+                    if (entry->getColumn() >= offset) {
+                        // Change column
+                        entry->setColumn(replacements[entry->getColumn() - offset]);
+                        changed = true;
                     }
+                    maxColumn = std::max(maxColumn, entry->getColumn());
                 }
-            } else {
-                for (index_type i = 0; i < rowIndications.size(); ++i) {
-                    endRows = i < rowIndications.size()-1 ? rowIndications[i+1] : columnsAndValues.size();
-                    // Sort the row
-                    std::sort(columnsAndValues.begin() + rowIndications[i], columnsAndValues.begin() + endRows,
+                if (changed) {
+                    // Sort columns in row
+                    std::sort(startRow, endRow,
                               [](MatrixEntry<index_type, value_type> const& a, MatrixEntry<index_type, value_type> const& b) {
                                   return a.getColumn() < b.getColumn();
                               });
                     // Assert no equal elements
-                    STORM_LOG_ASSERT(std::is_sorted(columnsAndValues.begin() + rowIndications[i], columnsAndValues.begin() + endRows,
-                                          [](MatrixEntry<index_type, value_type> const& a, MatrixEntry<index_type, value_type> const& b) {
-                                              return a.getColumn() <= b.getColumn();
-                                          }), "Columns not sorted.");
+                    STORM_LOG_ASSERT(std::is_sorted(startRow, endRow,
+                                                    [](MatrixEntry<index_type, value_type> const& a, MatrixEntry<index_type, value_type> const& b) {
+                                                        return a.getColumn() < b.getColumn();
+                                                    }), "Columns not sorted.");
                 }
-
             }
+
+            highestColumn = maxColumn;
+            lastColumn = columnsAndValues[columnsAndValues.size() - 1].getColumn();
         }
 
         template<typename ValueType>
diff --git a/src/storage/SparseMatrix.h b/src/storage/SparseMatrix.h
index c170d43a9..5d9f48fe9 100644
--- a/src/storage/SparseMatrix.h
+++ b/src/storage/SparseMatrix.h
@@ -230,9 +230,8 @@ namespace storm {
              *
              * @param replacements Mapping indicating the replacements from offset+i -> value of i.
              * @param offset Offset to add to each id in vector index.
-             * @return True if replacement took place, False if nothing changed.
              */
-            bool replaceColumns(std::vector<index_type> const& replacements, index_type offset);
+            void replaceColumns(std::vector<index_type> const& replacements, index_type offset);
                         
         private:
             // A flag indicating whether a row count was set upon construction.
@@ -295,11 +294,6 @@ namespace storm {
             // Stores the currently active row group. This is used for correctly constructing the row grouping of the
             // matrix.
             index_type currentRowGroup;
-            
-            /*!
-             * Fixes the matrix by sorting the columns to gain increasing order again.
-             */
-            void fixColumns();
         };
         
         /*!