read_data.hpp

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// SPDX-License-Identifier: BSD-2-Clause
 
#ifndef cMHN_UTILITY_READ_DATA_H
#define cMHN_UTILITY_READ_DATA_H
 
#include <algorithm>
#include <fstream>
#include <map>
#include <sstream>
#include <string>
 
#include <prc.hpp>
 
namespace cMHN
{
    template<class T, pRC::Size D>
    static inline auto readData(std::string const &filename)
    {
        std::ifstream file(filename);
 
        using Subscripts =
            decltype(expand(pRC::makeConstantSequence<pRC::Size, D, 2>(),
                [](auto const... seq)
                {
                    return pRC::Subscripts<seq...>();
                }));
 
        if(!file.is_open())
        {
            pRC::Logging::error("Unable to open input file!");
        }
 
        std::map<Subscripts, T> pD;
 
        // number of samples
        pRC::UnsignedInteger<64> sum = 0;
 
        std::string line;
 
        // first line contains header (event names)
        std::getline(file, line);
 
        // write samples to pD
        while(std::getline(file, line))
        {
            // turn commas into spaces
            std::replace(line.begin(), line.end(), ',', ' ');
 
            std::istringstream iss(line);
 
            // store event data for current sample in 'bits'
            Subscripts bits;
            std::size_t i = 0;
            unsigned v;
            while(iss >> v)
            {
                bits[i++] = v;
            }
            if constexpr(pRC::cDebugLevel >= pRC::DebugLevel::Low)
            {
                if(i != D)
                {
                    pRC::Logging::error(
                        "Number of events differs for input file and binary. "
                        "File:",
                        i, "Binary:", D);
                }
            }
 
            pD.try_emplace(bits, pRC::zero<T>());
            pD[bits] += pRC::unit<T>();
 
            sum += pRC::unit<decltype(sum)>();
        }
 
        // normalize pD
        for(auto &[k, v] : pD)
        {
            v /= sum;
        }
 
        return pD;
    }
} // namespace cMHN
 
#endif // cMHN_UTILITY_READ_DATA_H