C++ std::threadの小手先だけの使い方

std::threadを何とか使う。

とりあえず動いた。配列はvectorに置換して。
#include <iostream>
#include <thread>
#include <vector>
#include <string>
#include "clMatrix.hpp"

template<typename T>
void fcShow(T data) {std::cout << data ;}
template<typename T, typename K>
void fcThreadWork_xxx(T& tA, T& tB,int iSf,int iEf) {
    for(int i=iSf;i<iEf;++i){
        K tmp;
        tmp = tA(i);
        tA(i) = tB(i);
        tB(i) = tmp;
        //std::swap(tA(i),tB(i));
    }
}
template<typename T>
void fcDump(string str,T& tX) {
    fcShow(str);
    int iSize = tX.fcGetSize();
    for (int i = 0; i < iSize; ++i) {
        fcShow(tX(i));
        fcShow(",");
    }
    fcShow("\n");
}
int main()
{
    int hoge = 100;
    const int iSize = hoge;

    mtd::clVector<double>dA(iSize); mtd::clVector<double>dB(iSize);
    for (int i = 0; i < iSize; ++i) {dA(i) = i;dB(i) = i * -10;}
    fcShow("■　■　■　ナイーブに交換　前　■　■　■\n");
    fcDump("dA:",dA); fcDump("dB:", dB);
    const double dThreadNumRatio = 0.5;
    int iThreadNum = (int)((double)std::thread::hardware_concurrency() * dThreadNumRatio);
    if (iThreadNum == 0) { iThreadNum = 2; }
    int iStep = (int)((double)iSize / (double)iThreadNum);

    std::vector<std::thread> obThreads(iThreadNum);
    // スレッドを生成
    for (int i = 0; i < iThreadNum; ++i) {
        int iS = 0, iE = 0;
        iS = i * iStep;
        if (i < iThreadNum -1) {
            iE = iS + iStep;
        } else {
            iE = iSize;
        }
        obThreads[i] = (std::thread(fcThreadWork_xxx<mtd::clVector<double>,double>, std::ref(dA), std::ref(dB), iS, iE));
        //threads.push_back(std::thread(fcSwapThWork, std::ref(dA), std::ref(dB), iS, iE));
    }

        // 各スレッドの終了を待つ
        for (auto& t : obThreads) {
            t.join();
        }
    
        fcShow("■　■　■　ナイーブに交換　後　■　■　■\n");
        fcDump("dA:", dA); fcDump("dB:", dB);
        std::cout << "Hello World!\n";
}

引用　google で　std::thread　を検索。そのウェブページ