Fast5x5

A linear algebra library which focus on 5x5 operations.

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Using the library

Dependencies

Fast5x5 is a template-based header-only library, relying on xsimd (>= 5.0.0). The only usage requirement is to correctly add the xsimd include directories to the list of directories used by your compiler.

Importing

There is only one header to import in order to use the library:

#include "../path/to/Fast5x5/fast5x5.hpp"

Creating a matrix

In order to create a matrix you need to create a object from the BaseMatrix<Type, NRows, NCols> class where NRows and NCols are the matrix dimensions.

BaseMatrix<float, 2, 3> my_matrix;

By default your matrix will be initialized to zero. If you want to initialize it to existing values you can pass an array to the constructor. Values in the array are considered to be row-major.

double data[16] {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16};
BaseMatrix<double, 4, 4> my_matrix(data);

Getting the data back

You can dump the matrix data with the dump_array() method. The returned value is an std::array in row-major order.

std::array<double, 4*4> data = my_matrix.dump_array();

Printing values

BaseMatrix objects are printable with the << operator:

std::cout << my_matrix << std::endl;

Simple example

This is a simple example for matrix multiplication.

#include <iostream>

#include "../Fast-Matrix/fast5x5.hpp"

int main (int argc, char **argv) {
    float left_data[6] = {
        1, 2, 3,
        4, 5, 6
    };
    float right_data[6] = {
        7, 8,
        9, 10,
        11, 12
    };

    BaseMatrix<float, 2, 3> a(left_data);
    BaseMatrix<float, 3, 2> b(right_data);
    BaseMatrix<float, 2, 2> c;

    matrix_mul_m_m(a, b, c); // The matrix product c = a*b

    std::cout << "A" << std::endl << a << std::endl;
    std::cout << "B" << std::endl << b << std::endl;
    std::cout << "C = A * B" << std::endl << c << std::endl;
}

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Testing

Testing functionalities of the library is available through a set of unit tests. Prior running the tests you must build them with cmake. Building them require to install xsimd first.

Additional dependencies

• cmake (>= 3.4)
• eigen 3.2.10
• googletest 1.8.