Eigen Read Files

read_matrix.cpp

// Original Code http://goo.gl/P0sED6

#include <iostream>
#include <fstream>
#include <string>
#include <Eigen/Dense>

using namespace std;
using namespace Eigen;

#define MAXBUFSIZE  ((int) 1e6)

MatrixXd readMatrix(const char *filename)
    {
    int cols = 0, rows = 0;
    double buff[MAXBUFSIZE];

    // Read numbers from file into buffer.
    ifstream infile;
    infile.open(filename);
    while (! infile.eof())
        {
        string line;
        getline(infile, line);

        int temp_cols = 0;
        stringstream stream(line);
        while(! stream.eof())
            stream >> buff[cols*rows+temp_cols++];

        if (temp_cols == 0)
            continue;

        if (cols == 0)
            cols = temp_cols;

        rows++;
        }

    infile.close();

    rows--;

    // Populate matrix with numbers.
    MatrixXd result(rows,cols);
    for (int i = 0; i < rows; i++)
        for (int j = 0; j < cols; j++)
            result(i,j) = buff[ cols*i+j ];

    return result;
}

read_vector.cpp

// Modified code of http://goo.gl/P0sED6

#include <iostream>
#include <fstream>
#include <string>
#include <Eigen/Dense>

using namespace std;
using namespace Eigen;

#define MAXBUFSIZE  ((int) 1e6)

VectorXd readVector(const char *filename){ // http://goo.gl/P0sED6
	int length=0;
	double buff[MAXBUFSIZE];

	// Read numbers into buffer
	ifstream infile;
	infile.open(filename);
	int temp_cols=0;
	while (! infile.eof()){
		string line;
		getline(infile, line);
		stringstream stream(line);
		stream >> buff[temp_cols++];
		
		if(temp_cols==0)
			continue;

		length++; // keep vector length

	} // close while ! infile.eof()

	infile.close();
	//rows--;

	// return vector
	VectorXd result(length);
	for(int i=0; i<length; i++){
		result[i] = buff[i];
	} //close for(i)
	
	return result;
}