utilities.cpp

来自「amygdata的神经网络算法源代码」· C++ 代码 · 共 98 行

/***************************************************************************
                          utilities.cpp  -  description
                             -------------------
    begin                : Wed May 22 2002
    copyright            : (C) 2002 by Rdiger Koch
    email                : [e-mail]
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

using namespace std;
#include "utilities.h"

#include <cmath>
#include <stdlib.h>

#include <sstream>
#include <string>
#include <stdexcept>

#include <sys/types.h>
#include <sys/stat.h>

float Utilities::GaussRand(float mean, float sigma)
{
    // Based on code from the GNU Scientific Library
    // and _Numerical Recipes in C_
	float randVal, xuniRand, yuniRand;
    float x, y, r2;

  	do {
      	// choose x,y in uniform square (-1,-1) to (+1,+1)
		xuniRand = float(rand()) / float(RAND_MAX);
		yuniRand = float(rand()) / float(RAND_MAX);

		x = -1 + 2 * xuniRand;
      	y = -1 + 2 * yuniRand;

      	// see if it is in the unit circle
       	r2 = x * x + y * y;
    } while (r2 > 1.0 || r2 == 0);

  	// Box-Muller transform
  	randVal = sigma * y * sqrt(-2.0 * log(r2) / r2);
	return (randVal + mean);
}

float Utilities::RandPercent()
{
    return ( float(rand()) / float(RAND_MAX) ) * 100.0;
}


string Utilities::itostr(int val){
    ostringstream o;
    if (o << val)
        return o.str();
    else
        throw runtime_error("cannot convert integer to string");

    return "";
}


string Utilities::ftostr(float val){
    ostringstream o;
    if (o << val)
        return o.str();
    else
        throw runtime_error("cannot convert float to string");

    return "";
}


void Utilities::RoundTime(AmTimeInt& time, const AmTimeInt& stepSize)
{
    double tmpTime;
    double roundTime;

    tmpTime = (double)time / stepSize;
    tmpTime = modf(tmpTime, &roundTime);
    if (tmpTime > 0.5) {
        time = ((AmTimeInt)roundTime * stepSize) + stepSize;
    }
    else {
        time = (AmTimeInt)roundTime * stepSize;
    }
}