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From: micode on 2 Jun 2010 05:06
The std::random replacement for std::tr1::random utilizes a couple of
different naming conventions. Apparently this is based on whether the
distribution has well-accepted names such as mean, sigma or lambda.
The result is, however, non-uniform naming which means each developer
may end up reimplementing an uniform-naming layer. Not a big problem,
but just one more source of potential errors. This means different
construction of the simple output methods for the basic parameters,
i.e.:

void describe_normal() { cout << r_normal.mean() << ", " <<
r_normal.stddev() << endl; }
void describe_lognormal() { cout << r_lognormal.m() << ", " <<
r_lognormal.s() << endl; }

Full Example (compiles with -std=c++0x under GCC)

#include <iostream>
#include <numeric>
#include <random>
#include <vector>
#include <sstream>

using namespace std;
typedef double RealType;
typedef long long IntType;
typedef mt19937_64 dist_engine;
typedef normal_distribution<RealType> dist_normal;
typedef lognormal_distribution<RealType> dist_lognormal;

class rgen {
private:
dist_engine engine;
dist_normal r_normal;
dist_lognormal r_lognormal;
public:
rgen(long seed = 0,
/*Normal*/
RealType nMean=0, RealType nSigma=1,
/*Log normal*/
RealType lognrmM=0, RealType lognrmS=1) :
engine(seed==0?random():seed),
r_normal(dist_normal::param_type(nMean,nSigma)),
r_lognormal(dist_lognormal::param_type(lognrmM,lognrmS)) {}

RealType normal() { return r_normal(engine); }
RealType lognormal() { return r_lognormal(engine); }
RealType normal(RealType mean, RealType sigma) {
return r_normal(engine, dist_normal::param_type(mean,sigma)); }
RealType lognormal(RealType m, RealType s) {
return r_lognormal(engine, dist_lognormal::param_type(m,s)); }

/* DIFFERENT MEMBER NAMES CORRESPOND TO CONVENTIONS */
/* USE OF operator<< and operator>> DOESN'T REALLY SOLVE THIS */
void describe_normal() { cout << r_normal.mean() << ", " <<
r_normal.stddev() << endl; }
void describe_lognormal() { cout << r_lognormal.m() << ", " <<
r_lognormal.s() << endl; }
};

--
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