pjessesco / peanut

🥜 Simple header-only C++20 matrix library using expression templates

Peanut

Peanut is a header-only matrix library using C++20 without any external dependencies, (except unit test), following a expression templates concept. It first constructs matrix expression as a user provides, and evaluates it using an automatically generated code in a compile-time.

Matrix<int, 4, 4> mat1{1,2,3,4,
                       1,2,3,4,
                       1,2,3,4,
                       1,2,3,4};

Matrix<int, 3, 5> mat2{1,2,3,4,5,
                       1,2,3,4,5,
                       1,2,3,4,5};

// Peanut first build expression tree,
// `result` type is `MatrixMult<MatrixSubtract<MatrixSum<Matrix<int, 4, 4>, MatrixInverse<Matrix<int, 4, 4>>>, MatrixMinor<Matrix<int, 4, 4>>>, MatrixSub<2, 1, MatrixMult<MatrixTranspose<Matrix<int, 3, 5>>, Matrix<int, 3, 5>>>>`.
auto result = (mat1 + Inverse(mat1) - Minor(mat1)) * SubMat<2, 1>(T(mat2) * mat2);

// then evaluate it when `eval()` is called or assigned to `Matrix` type variable.
/* Matrix<int, 4, 4> */ auto e1 = result.eval();
Matrix<int, 4, 4> e2 = result;

Features

• Arbitrary size matrix expression
• Lazy evaluation
• Unit test

Usage

Copy Peanut directory to your project, and add and its path to the include path. If you're using CMake, add :

add_subdirectory(ext/peanut)
include_directories(ext/peanut/include)

Then include as below :

#include <Peanut/Peanut.h>

Refer documentation for more information.