createDist.cpp

#include <fstream>
#include <vector>
#include <iostream>

/*This script can create a custom discrete distribution from a given interval and given function.
More complex distributions may require if else cases to switch between different generation functions in function().
*/

//----- TO MODIFY ------
// Globals
double X_MIN = 0.0;
double X_MAX = 2.0;
double DELTA = 0.01;
std::string OUT_FILE_PATH = "customDist.txt";

// generation function
inline double function(double x)
{
    return 10.0 * x;
}
//----- xxxxxxxxx ------

// creates a vector of doubles with lenght int((min-max)/delta)
// excludes max if (max-min)%delta != 0
std::vector<double> linspace(double min, double max, double delta)
{
    int nSteps = int((max - min) / delta);
    std::vector<double> x(nSteps + 1);
    for (size_t i = 0; i < nSteps + 1; i++)
    {
        x.at(i) = min + i * delta;
    }
    return x;
}

std::vector<double> makeDist(double xmin, double xmax, double delta)
{
    // generate linspace
    std::vector<double> x = linspace(xmin, xmax, delta);
    // set each element of x to f(x)
    for (auto &element : x)
    {
        element = function(element);
    }
    return x;
}

void printDist(std::vector<double> v)
{
    for (const auto &element : v)
    {
        std::cout << element << std::endl;
    }
}

void saveVec(std::vector<double> v, std::string filename)
{
    std::ofstream out;
    out.open(filename);
    if (out.is_open())
    {
        std::cout << "Opened \'" << filename << "\' successfully" << std::endl;
        for (const auto &element : v)
        {
            out << element << " ";
        }
        out << std::endl;
    }
    else
    {
        std::cout << "File \'" << filename << "\' can't be opened\n Abort saving file";
    }
}

int main()
{
    std::vector<double> distribution = makeDist(X_MIN, X_MAX, DELTA);
    saveVec(distribution, OUT_FILE_PATH);
}