New methods for the SparseMatrix: SetRowGroupIndices and filterEntries

src/storm/storage/SparseMatrix.cpp

@@ -584,6 +584,27 @@ namespace storm {
             return rowGroupIndices.get();
         }
 
+        template<typename ValueType>
+        void SparseMatrix<ValueType>::setRowGroupIndices(std::vector<index_type> const& newRowGroupIndices) {
+            trivialRowGrouping = false;
+            rowGroupIndices = newRowGroupIndices;
+        }
+
+        template<typename ValueType>
+        bool SparseMatrix<ValueType>::hasTrivialRowGrouping() const {
+            return trivialRowGrouping;
+        }
+        
+        template<typename ValueType>
+        void SparseMatrix<ValueType>::makeRowGroupingTrivial() {
+            if (trivialRowGrouping) {
+                STORM_LOG_ASSERT(!rowGroupIndices || rowGroupIndices.get() == storm::utility::vector::buildVectorForRange(0, this->getRowGroupCount() + 1), "Row grouping is supposed to be trivial but actually it is not.");
+            } else {
+                trivialRowGrouping = true;
+                rowGroupIndices = boost::none;
+            }
+        }
+        
         template<typename ValueType>
         storm::storage::BitVector SparseMatrix<ValueType>::getRowFilter(storm::storage::BitVector const& groupConstraint) const {
             storm::storage::BitVector res(this->getRowCount(), false);
@@ -984,6 +1005,30 @@ namespace storm {
             return res;
         }
         
+        template<typename ValueType>
+        SparseMatrix<ValueType> SparseMatrix<ValueType>::filterEntries(storm::storage::BitVector const& rowFilter) const {
+            // Count the number of entries in the resulting matrix.
+            index_type entryCount = 0;
+            for (auto const& row : rowFilter) {
+                entryCount += getRow(row).getNumberOfEntries();
+            }
+            
+            // Build the resulting matrix.
+            SparseMatrixBuilder<ValueType> builder(getRowCount(), getColumnCount(), entryCount);
+            for (auto const& row : rowFilter) {
+                for (auto const& entry : getRow(row)) {
+                    builder.addNextValue(row, entry.getColumn(), entry.getValue());
+                }
+            }
+            SparseMatrix<ValueType> result = builder.build();
+            
+            // Add a row grouping if necessary.
+            if (!hasTrivialRowGrouping()) {
+                result.setRowGroupIndices(getRowGroupIndices());
+            }
+            return result;
+        }
+        
         template<typename ValueType>
         SparseMatrix<ValueType> SparseMatrix<ValueType>::selectRowsFromRowGroups(std::vector<index_type> const& rowGroupToRowIndexMapping, bool insertDiagonalEntries) const {
             // First, we need to count how many non-zero entries the resulting matrix will have and reserve space for
@@ -1547,22 +1592,7 @@ namespace storm {
         typename SparseMatrix<ValueType>::iterator SparseMatrix<ValueType>::end()  {
             return this->columnsAndValues.begin() + this->rowIndications[rowCount];
         }
-        
-        template<typename ValueType>
-        bool SparseMatrix<ValueType>::hasTrivialRowGrouping() const {
-            return trivialRowGrouping;
-        }
-        
-        template<typename ValueType>
-        void SparseMatrix<ValueType>::makeRowGroupingTrivial() {
-            if (trivialRowGrouping) {
-                STORM_LOG_ASSERT(!rowGroupIndices || rowGroupIndices.get() == storm::utility::vector::buildVectorForRange(0, this->getRowGroupCount() + 1), "Row grouping is supposed to be trivial but actually it is not.");
-            } else {
-                trivialRowGrouping = true;
-                rowGroupIndices = boost::none;
-            }
-        }
-        
+
         template<typename ValueType>
         ValueType SparseMatrix<ValueType>::getRowSum(index_type row) const {
             ValueType sum = storm::utility::zero<ValueType>();

src/storm/storage/SparseMatrix.h

@@ -563,6 +563,27 @@ namespace storm {
              */
             std::vector<index_type> const& getRowGroupIndices() const;
             
+            /*!
+             * Sets the row grouping to the given one.
+             * @note It is assumed that the new row grouping is non-trivial.
+             *
+             * @param newRowGroupIndices The new row group indices.
+             */
+            void setRowGroupIndices(std::vector<index_type> const& newRowGroupIndices);
+            
+            /*!
+             * Retrieves whether the matrix has a trivial row grouping.
+             *
+             * @return True iff the matrix has a trivial row grouping.
+             */
+            bool hasTrivialRowGrouping() const;
+            
+            /*!
+             * Makes the row grouping of this matrix trivial.
+             * Has no effect when the row grouping is already trivial.
+             */
+            void makeRowGroupingTrivial();
+
             /*!
              * Returns the indices of the rows that belong to one of the selected row groups.
              *
@@ -665,6 +686,15 @@ namespace storm {
              */
             SparseMatrix restrictRows(storm::storage::BitVector const& rowsToKeep, bool allowEmptyRowGroups = false) const;
             
+            /*!
+             * Returns a copy of this matrix that only considers entries in the selected rows.
+             * Non-selected rows will not have any entries
+             *
+             * @note does not change the dimensions (row-, column-, and rowGroup count) of this matrix
+             * @param rowFilter the selected rows
+             */
+            SparseMatrix filterEntries(storm::storage::BitVector const& rowFilter) const;
+            
             /**
              * Compares two rows.
              * @param i1 Index of first row
@@ -1004,19 +1034,6 @@ namespace storm {
              */
             iterator end();
             
-            /*!
-             * Retrieves whether the matrix has a trivial row grouping.
-             *
-             * @return True iff the matrix has a trivial row grouping.
-             */
-            bool hasTrivialRowGrouping() const;
-            
-            /*!
-             * Makes the row grouping of this matrix trivial.
-             * Has no effect when the row grouping is already trivial.
-             */
-            void makeRowGroupingTrivial();
-
 			/*!
 			* Returns a copy of the matrix with the chosen internal data type
 			*/