EigenMatLib.h : C++行列演算ライブラリEigenを使った，MATLABの便利関数を模倣したヘッダライブラリ．

EigenMatLib.h

//-------------------------------------------------------------------------
//
// File : EigenMatLib.m
//
// Discription : Eigen Library inspired by Matlab functions.
//
// Environment : C++
//
// Author : Atsushi Sakai
//
// Copyright (c): 2013 Atsushi Sakai
//
// License : Modified BSD Software License Agreement
//-------------------------------------------------------------------------

#ifndef INCLUDED_EIGENMATLIB
#define INCLUDED_EIGENMATLIB

#include <Eigen/Dense>

using namespace Eigen;
using namespace std;

// Standard deviation
// input
//  X:data vector
//  flag: 0 or 1 
//  dim : 1 or 2
// output
//  stdResult: Standar deviation value. 
//              if an error is detected, empty matrix will resturn.

MatrixXf Std(const MatrixXf& X,int flag,int dim){
  MatrixXf stdResult;
  if(X.size()==0){//data size check
    cout<<"Error Std:Input data is empty."<<endl;
  }
  if(flag<0||flag>1){//flag check
    cout<<"Error Std:flag is imvalid."<<endl;
  }
  if(dim<1||dim>2){//flag check
    cout<<"Error Std:dim is imvalid."<<endl;
  }

  int ncol=X.cols();
  int nrow=X.rows();
  if(dim==1){//row-wise
    stdResult.resize(1,ncol);
    double mean;
    for(int i=0;i<ncol;i++){
      mean=X.col(i).mean(); 
      stdResult(0,i)=(X.col(i)-MatrixXf::Constant(nrow,1,mean)).squaredNorm();
      if(flag==0){
        if(nrow>1){
          stdResult(0,i)=sqrt(stdResult(0,i)/(nrow-1));
        }
        else{
          stdResult(0,i)=0;
        }
      }
      else{
        stdResult(0,i)=sqrt(stdResult(0,i)/nrow);
      }
    }
  }
  else{//col-wise
    stdResult.resize(nrow,1);
    double mean;
    for(int i=0;i<nrow;i++){
      mean=X.row(i).mean(); 
      stdResult(i,0)=(X.row(i)-MatrixXf::Constant(1,ncol,mean)).squaredNorm();
      if(flag==0){
        if(ncol>1){
          stdResult(i,0)=sqrt(stdResult(i,0)/(ncol-1));
        }
        else{
          stdResult(0,i)=0;
        }
      }
      else{
        stdResult(i,0)=sqrt(stdResult(i,0)/ncol);
      }
    }
  }

  return stdResult;
}

#endif