ConstexprMath

A header-only C++ library providing compile-time mathematical operations that work with both individual arithmetic arguments and containers (like arrays and standard containers).

Features

• All functions are constexpr and can be evaluated at compile time
• Support for both variadic arguments and container-based inputs
• Uses C++20 concepts for compile-time type checking

Installation

Currently available Functions

Available Methods

• sum() - Calculate the sum of values
• abs() - Get absolute values
• min() - Find the minimum value
• max() - Find the maximum value
• mean() - Calculate the arithmetic mean
• variance() - Calculate the variance
• dot() - Calculate the dot product of two containers

Requirements

• C++20 compatible compiler
• Standard Library headers:

<type_traits>, <concepts>, <array>, <algorithm>

Basic Examples

    // Using variadic arguments
    constexpr auto s = cm::sum(1, 2, 3, 4, 5);  // Returns 15
    constexpr auto m = cm::mean(1.0, 2.0, 3.0); // Returns 2.0
    constexpr auto mx = cm::max(5, 3, 8, 2);    // Returns 8

    // Using containers
    constexpr std::array<int, 5> arr{1, 2, 3, 4, 5};
    constexpr auto arr_sum = cm::sum(arr);       // Returns 15
    constexpr auto arr_mean = cm::mean(arr);     // Returns 3.0

    // Dot product example
    constexpr std::array<int, 3> a{1, 2, 3};
    constexpr std::array<double, 3> b{1.5, 2.5, 3.5};
    constexpr std::array<double, 4> c{1.5, 2.5, 3.5,3.4};

    constexpr auto dot_result = cm::dot<3, 3>(a, b); // Returns 17.0
    constexpr auto dot_result = cm::dot<3, 4>(a, c); // static assertion 
    static_assert(cm::sum(1, 2, 3) == 6, "Compile-time check");
    //use static_assert to verify compile-time evaluation

Type Requirements

• Variadic functions require all arguments to be arithmetic types

• Container functions require containers that:

  • Have begin() and end() methods
  • Contain arithmetic types
  • Are not arithmetic types themselves

Supported containers

std::array, std::vector
(generally speaking std::vector is not a constexpr container, so be carful using it if you want constexpr calculations)

what i learned

• not all containers can be used at compile time
• basics of concepts type traits
• decltype is useful to give your types custom names
• decay_t can be used to remove constness/refererences
• decay_t is just an alias for accessing the member function std::decay::type
• conexpr calculations
• auto decays to int if not specified differently
• usage of static cast and static assert
• basic usage of variadic templates/fold expressions