86 lines
3.1 KiB
C++
86 lines
3.1 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2015 Olga Diamanti <olga.diam@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License
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// v. 2.0. If a copy of the MPL was not distributed with this file, You can
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// obtain one at http://mozilla.org/MPL/2.0/.
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#ifndef IGL_DIJKSTRA
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#define IGL_DIJKSTRA
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#include "igl_inline.h"
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#include <Eigen/Core>
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#include <vector>
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#include <set>
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namespace igl {
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// Dijkstra's algorithm for vertex-weighted shortest paths, with multiple targets.
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// Adapted from http://rosettacode.org/wiki/Dijkstra%27s_algorithm .
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//
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// Inputs:
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// source index of source vertex
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// targets target vector set
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// VV #V list of lists of incident vertices (adjacency list), e.g.
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// as returned by igl::adjacency_list
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// weights #V list of scalar vertex weights
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//
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// Output:
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// min_distance #V by 1 list of the minimum distances from source to all vertices
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// previous #V by 1 list of the previous visited vertices (for each vertex) - used for backtracking
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//
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template <typename IndexType, typename DerivedD, typename DerivedP>
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IGL_INLINE int dijkstra(
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const IndexType &source,
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const std::set<IndexType> &targets,
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const std::vector<std::vector<IndexType> >& VV,
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const std::vector<double>& weights,
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Eigen::PlainObjectBase<DerivedD> &min_distance,
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Eigen::PlainObjectBase<DerivedP> &previous);
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// Dijkstra's algorithm for shortest paths, with multiple targets.
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// Adapted from http://rosettacode.org/wiki/Dijkstra%27s_algorithm .
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//
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// Inputs:
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// source index of source vertex
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// targets target vector set
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// VV #V list of lists of incident vertices (adjacency list), e.g.
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// as returned by igl::adjacency_list
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//
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// Output:
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// min_distance #V by 1 list of the minimum distances from source to all vertices
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// previous #V by 1 list of the previous visited vertices (for each vertex) - used for backtracking
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//
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template <typename IndexType, typename DerivedD, typename DerivedP>
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IGL_INLINE int dijkstra(
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const IndexType &source,
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const std::set<IndexType> &targets,
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const std::vector<std::vector<IndexType> >& VV,
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Eigen::PlainObjectBase<DerivedD> &min_distance,
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Eigen::PlainObjectBase<DerivedP> &previous);
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// Backtracking after Dijkstra's algorithm, to find shortest path.
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//
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// Inputs:
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// vertex vertex to which we want the shortest path (from same source as above)
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// previous #V by 1 list of the previous visited vertices (for each vertex) - result of Dijkstra's algorithm
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//
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// Output:
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// path #P by 1 list of vertex indices in the shortest path from source to vertex
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//
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template <typename IndexType, typename DerivedP>
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IGL_INLINE void dijkstra(
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const IndexType &vertex,
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const Eigen::MatrixBase<DerivedP> &previous,
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std::vector<IndexType> &path);
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};
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#ifndef IGL_STATIC_LIBRARY
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#include "dijkstra.cpp"
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#endif
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#endif /* defined(IGL_DIJKSTRA) */
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