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realroot_doc 0.1.1
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realroot_doc 0.1.1
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00001 /******************************************************************** 00002 * This file is part of the source code of the realroot library. 00003 * Author(s): J.P. Pavone, GALAAD, INRIA 00004 * $Id: binomials.hpp,v 1.1 2005/07/11 10:03:55 jppavone Exp $ 00005 ********************************************************************/ 00006 #ifndef realroot_SOLVE_SBDSLV_BERNSTEIN_BINOMIALS_H 00007 #define realroot_SOLVE_SBDSLV_BERNSTEIN_BINOMIALS_H 00008 //-------------------------------------------------------------------- 00009 #include <vector> 00010 #include <assert.h> 00011 //==================================================================== 00012 namespace mmx { 00013 //-------------------------------------------------------------------- 00014 namespace bernstein 00015 { 00016 template<typename T> 00017 struct binomials 00018 { 00019 static binomials _default_; 00020 std::vector< T * > m_data; 00021 binomials( const binomials& ); 00022 static void pwsum( T * dst, T * src, int sz ) { for(int i=0;i<sz-1;dst[i]=src[i]+src[i+1],i++) ; }; 00023 binomials( int dmax = 100 ) 00024 { 00025 m_data.push_back( new T[1] ); 00026 m_data[0][0] = 1; 00027 }; 00028 ~binomials() { 00029 for ( unsigned i = 0; i < m_data.size(); i ++ ) 00030 delete[] m_data[i]; 00031 00032 }; 00033 inline T * get( unsigned i ) 00034 { 00035 if ( m_data.size() > i ) return m_data[i]; 00036 for ( unsigned j = m_data.size(); j <= i; j ++ ) 00037 { 00038 m_data.push_back( new T[j+1] ); 00039 pwsum(m_data[j]+1,m_data[j-1],j); 00040 m_data[j][0] = 1; 00041 m_data[j][j] = 1; 00042 }; 00043 return m_data[i]; 00044 }; 00045 const T& binomial( unsigned n, unsigned i ) 00046 { return get(n)[i]; }; 00047 }; 00048 template<typename T> 00049 binomials<T> binomials<T>::_default_; 00050 template<typename T> 00051 T binomial( int n, int i ) { return binomials<T>::_default_.binomial(n,i); }; 00052 }; 00053 //-------------------------------------------------------------------- 00054 } //namespace mmx 00055 /********************************************************************/ 00056 #endif //
