DGtal 1.3.0
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exampleBoundedLatticePolytopeCount2D.cpp
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1
58#include "DGtal/base/Common.h"
59#include "DGtal/geometry/volumes/ConvexityHelper.h"
60#include "DGtal/geometry/volumes/BoundedLatticePolytope.h"
61
62int main( int argc, char* argv[] )
63{
64 int N = argc > 1 ? atoi( argv[ 1 ] ) : 1000; // nb of polytopes
65 int nb = argc > 2 ? atoi( argv[ 2 ] ) : 10; // nb points per polytope
66 int R = argc > 3 ? atoi( argv[ 3 ] ) : 200; // max diameter of shape
67
68 typedef int64_t Integer;
71 typedef Helper::LatticePolytope Polytope;
72 typedef Polytope::Point Point;
73 // Compute all polytopes
74 DGtal::trace.beginBlock( "Compute 2D polytopes" );
75 std::vector< Polytope > polytopes;
76 int sum_nb_facets = 0;
77 for ( int i = 0; i < N; i++ )
78 {
79 std::vector< Point > V;
80 for ( int i = 0; i < nb; i++ ) {
81 Point p( rand() % (2*R+1) - R, rand() % (2*R+1) - R );
82 V.push_back( p );
83 }
84 Polytope P = Helper::computeLatticePolytope( V );
85 sum_nb_facets += P.nbHalfSpaces();
86 polytopes.push_back( P );
87 }
88 double t1 = DGtal::trace.endBlock();
89 DGtal::trace.info() << "Computed " << N
90 << " 2D polytopes with " << ( sum_nb_facets / (double) N )
91 << " facets on average, in " << t1 << " ms." << std::endl;
92 // Count interior points (slow method)
93 DGtal::trace.beginBlock( "Compute number of lattice points within polytope (slow)" );
94 std::size_t slow_nb = 0;
95 std::vector< Integer > slow_counts;
96 for ( const auto& P : polytopes )
97 {
98 const auto nb = P.countByScanning();
99 slow_nb += nb;
100 slow_counts.push_back( nb );
101 }
102 double t2 = DGtal::trace.endBlock();
103 // Count interior points (fast method)
104 DGtal::trace.beginBlock( "Compute number of lattice points within polytope (fast)" );
105 std::size_t fast_nb = 0;
106 std::vector< Integer > fast_counts;
107 for ( const auto& P : polytopes )
108 {
109 const auto nb = P.count();
110 fast_nb += nb;
111 fast_counts.push_back( nb );
112 }
113 double t3 = DGtal::trace.endBlock();
114 bool ok = std::equal( slow_counts.cbegin(), slow_counts.cend(), fast_counts.cbegin() );
115 DGtal::trace.info() << "Computed inside points is " << ( ok ? "OK" : "ERROR" ) << std::endl;
116 DGtal::trace.info() << "Reference method computed " << slow_nb
117 << " points in " << t2 << " ms." << std::endl;
118 DGtal::trace.info() << "Fast method computed " << fast_nb
119 << " points in " << t3 << " ms." << std::endl;
120 return 0;
121}
122
void beginBlock(const std::string &keyword="")
std::ostream & info()
double endBlock()
Point::Coordinate Integer
Trace trace
Definition: Common.h:154
Aim: Provides a set of functions to facilitate the computation of convex hulls and polytopes,...
int main()
Definition: testBits.cpp:56
MyPointD Point
Definition: testClone2.cpp:383