Cpp Basics - ashBabu/Utilities GitHub Wiki

#include <iostream>
#include <execution>
#include <vector>

int main()
{
   std::vector<int> v{1, 22, 54, 87, 56, 98};
   std::sort(std::execution::par, v.begin(), v.end());
   
   return 0;
}

#include <iostream>
#include <vector>
#include <tbb/tbb.h>
#include <chrono>

int summarize(const std::vector<int>& vec) {
    int sum = 0;
    for (int i = 0; i < vec.size(); ++i) {
    sum += vec[i];
    }
    return sum;
}

int summarize_tbb(const std::vector<int>& vec) 
{
    // Parallel summation using TBB
    int sum = tbb::parallel_reduce(
        tbb::blocked_range<std::size_t>{0, vec.size()}, // Range of indices to process
        0, // Initial value for local sums
        [&vec] (const auto& r, int init)
        {
            for (auto i = r.begin(); i != r.end(); ++i)
            {
                init += vec[i];
            }
            return init;
        },
        std::plus<int>{}
    );

    // Another way
    /* 
    // Parallel summation using TBB
    tbb::parallel_reduce(
        tbb::blocked_range<size_t>(0, N),  // Range of indices to process
        0,  // Initial value for local sums
        [&](const tbb::blocked_range<size_t>& range, int local_sum) -> int {
            for (size_t i = range.begin(); i < range.end(); ++i) {
                local_sum += numbers[i];
            }
            return local_sum;
        },
        [](int x, int y) -> int {
            return x + y;  // Combine local sums into the final result
        });
    */

    return sum;
}


int main() {
    // Create a large vector with numbers from 1 to 1,000,000
    const size_t N = 1'000'000;
    std::vector<int> numbers(N);
    for (size_t i = 0; i < N; ++i) {
        numbers[i] = i + 1;
    }

    // Variable to store the result
    auto start = std::chrono::steady_clock::now();
    int sum_result = summarize(numbers);
    auto end = std::chrono::steady_clock::now();
    auto duration = end - start;
    std::cout<< "The sum is "<< sum_result<< " and the time taken for normal summation is "<< duration.count() <<"\n";


    start = std::chrono::steady_clock::now();
    int sum_tbb = summarize_tbb(numbers);
    end = std::chrono::steady_clock::now();
    duration = end - start;
    std::cout<< "The sum is "<< sum_result<< " and the time taken for tbb summation is "<< duration.count() <<"\n";

    return 0;
}

cmake_minimum_required(VERSION 3.8)
project(tbb)

# find dependencies
find_package(TBB REQUIRED)

include_directories(
    include
)

add_executable(tbb
    tbb.cpp
)

target_link_libraries(tbb PRIVATE TBB::tbb)

The sum is 1784293664 and the time taken for normal summation is 5289687
The sum is 1784293664 and the time taken for tbb summation is 2713345

#include <iostream>
#include <vector>
#include <algorithm>

int main()
{
    int d=7, e=5;
    std::vector<int> v{2, 5, 8, 25, 77};
   
    std::for_each(v.begin(), v.end(), [](int x){std::cout<<x<<"\n"});  // just prints out all the numbers in v

    std::for_each(v.begin(), v.end(), [d](int x){
           if (x%d == 0}
              std::cout<<x<<" is divisible by "<<d<<"\n";
           else
              std::cout<<x<<" is not divisible by "<<d<<"\n";
    );  // d is accessible but cannot be changed inside the function

    std::for_each(v.begin(), v.end(), [&d](int x){
           if (x%d == 0}
              std::cout<<x<<" is divisible by "<<d<<"\n";
           else
              std::cout<<x<<" is not divisible by "<<d<<"\n";
        d = 10;
    );  // d is accessible and can be changed inside the function
}

int main()
{
    [[maybe_unused]] double pi { 3.14159 };
    [[maybe_unused]] double gravity { 9.8 };
    [[maybe_unused]] double phi { 1.61803 };

    std::cout << pi << '\n';
    std::cout << phi << '\n';

    // The compiler will no longer warn about gravity not being used

    return 0;
}

#include<iostream>

void print()
{
    std::cout<<"Hello_Ash  "<<std::endl;
}

#include <unistd.h>
#include <limits.h>
#include <string>

std::string getExePath()
{
    char result[ PATH_MAX ];
    ssize_t count = readlink( "/proc/self/exe", result, PATH_MAX );
    std::string path = std::string( result, (count > 0) ? count : 0 );
    std::string::size_type pos = path.find_last_of("\\/");
    return path.substr(0, pos);
}

install(TARGETS HAILaser_datafusion_app
        DESTINATION "${CMAKE_INSTALL_PREFIX}/bin/")

install(DIRECTORY "${CMAKE_SOURCE_DIR}/tests/config/"
        DESTINATION "${CMAKE_INSTALL_PREFIX}/bin/datafusion_app/yaml_configs/"
        FILES_MATCHING PATTERN "*.yaml"  # only the yamls
)

int main(int argc, char *argv[])
{
    std::string current_directory = getExePath();
    std::cout<<"THE CURRENT WORKING DIRECTORY is"<< current_directory << std::endl;
    std::string path_to_yaml = current_directory + "/datafusion_app/yaml_configs/HDF_RAW_V2.yaml";
    std::cout<<"PATH TO YAML IS: " << path_to_yaml<<std::endl;

}

cmake -S . -B build
cmake --build build
cmake --build build -t test

cmake_minimum_required(VERSION 3.15...3.21)

project(MyProject
  VERSION
    1.0
  DESCRIPTION
    "Very nice project"
  LANGUAGES
    CXX
)

add_executable(myexample simple.cpp)