/home/pxiang/workspace_new/CalculateGreenFunction/src/Utility/random_generator.h

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/*
 * random_generator.h
 *
 *  Created on: Dec 17, 2013
 *      Author: pxiang
 */

#ifndef RANDOM_GENERATOR_H_
#define RANDOM_GENERATOR_H_

#include "types.h"

class RandomNumberGenerator {
        private:
                unsigned seed;

        public:


// constructor
        RandomNumberGenerator(unsigned inputSeed) {
                seed = inputSeed;
                srand(seed);
        }

        // default constructor
        RandomNumberGenerator() {
                //use the current time as seed for random numbers
                seed = (unsigned)time(NULL);
                srand(seed);
        }

        void SetSeed(unsigned inputSeed) {
                seed = inputSeed;
                srand(seed);
        }

// produce a complex random number in [0, 1) + [0, 1)*I given the seed
        dcomplex randomComplex() {
                double randomReal = (double)rand()/(double)RAND_MAX;
                double randomImag = (double)rand()/(double)RAND_MAX;
                dcomplex rc = dcomplex(randomReal,randomImag);
                return rc;
        }

        // produce a complex random number in [0, 1) + [0, 1)*I given the seed
        double randomReal() {
                double random = (double)rand()/(double)RAND_MAX;
                return random;
        }


};

// generate a matrix of given dimension whose elements are random numbers in [0, 1)
class RandomNumberMatrix {
public:
        RandomNumberMatrix(int row_count, int col_count, unsigned seed) {
                rows = row_count;
                cols = col_count;
                m.resize(rows, cols);
                rng.SetSeed(seed);
                for (int i=0; i<rows; i++) {
                        for (int j=0; j<cols; ++j) {
                                m(i, j) = rng.randomReal();
                        }
                }
        }

        double operator()(const int r, const int c) const {
                return m(r, c);
        }


        ~RandomNumberMatrix() {
                m.resize(0, 0);
                rows = 0;
                cols = 0;
        }

private:
        DMatrix m;
        int rows;
        int cols;
        RandomNumberGenerator rng;
};



#endif

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