CPPLapack Code

//=============================================================================
//! Samll Real Double-precision Symmetric Matrix Class
template<long N> class dsymatrix_small
{
public:
  //////// data ////////
  static const long m =N;
  static const long n =N;
  double array[(N*(N+1))/2];
  
  //////// constructor ////////
  dsymatrix_small(){;}
  dsymatrix_small(const double& x){
    for(long k=0; k<(N*(N+1))/2; k++){ array[k]=x; }
  }
  ~dsymatrix_small(){;}
  
  //////// function ////////
  double& operator()(const long& i, const long& j);
  double  operator()(const long& i, const long& j) const;
  
  dsymatrix_small<N>& zero(){
    for(long i=0; i<N; i++){ for(long j=0; j<=i; j++){ (*this)(i,j)=0.; } }
    return *this;
  }
  dsymatrix_small<N>& identity(){
    zero();
    for(long k=0; k<N; k++){ (*this)(k,k)=1.; }
    return *this;
  }
  dsymatrix_small<N>& set(const long& i, const long& j, const double& v){
    (*this)(i,j)=v;
    return *this;
  }
  
  dgematrix_small<N,N> to_dgematrix_small() const{
    dgematrix_small<N,N> newmat;
    for(long i=0; i<N; i++){
      for(long j=0; j<=i; j++){ newmat(i,j)=(*this)(i,j); }
      for(long j=i+1; j<N; j++){ newmat(i,j)=(*this)(j,i); }
    }
    return newmat;
  }
  
  void write(const char* filename) const;
  void read(const char* filename);
};