1 files changed, 45 insertions, 0 deletions
diff --git a/include/phat/algorithms/standard_reduction.h b/include/phat/algorithms/standard_reduction.h
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+++ b/include/phat/algorithms/standard_reduction.h
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+/*  Copyright 2013 IST Austria
+    Contributed by: Ulrich Bauer, Michael Kerber, Jan Reininghaus
+
+    This file is part of PHAT.
+
+    PHAT is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    PHAT is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with PHAT.  If not, see <http://www.gnu.org/licenses/>. */
+
+#pragma once
+
+#include <phat/helpers/misc.h>
+#include <phat/boundary_matrix.h>
+
+namespace phat {
+    class standard_reduction {
+    public:
+        template< typename Representation >
+        void operator() ( boundary_matrix< Representation >& boundary_matrix ) {
+
+            const index nr_columns = boundary_matrix.get_num_cols();
+            std::vector< index > lowest_one_lookup( nr_columns, -1 );
+            
+            for( index cur_col = 0; cur_col < nr_columns; cur_col++ ) {
+                index lowest_one = boundary_matrix.get_max_index( cur_col );
+                while( lowest_one != -1 && lowest_one_lookup[ lowest_one ] != -1 ) {
+                    boundary_matrix.add_to( lowest_one_lookup[ lowest_one ], cur_col );
+                    lowest_one = boundary_matrix.get_max_index( cur_col );
+                }
+                if( lowest_one != -1 ) {
+                    lowest_one_lookup[ lowest_one ] = cur_col;
+                }
+            }
+        }
+    };
+}