`GF2::Matrix` — Bit Counts

The number of set/unset elements in a bit-matrix.

constexpr std::size_t count() const;              (1)
constexpr std::size_t count_diagonal() const;     (2)
constexpr bool trace() const;                     (3)

1	Returns the number of elements in the bit-matrix that are set to 1.
2	Returns the number of elements on the bit-matrix diagonal that are set to 1.
3	Returns `count_diagonal() % 2`--the “sum” of the diagonal elements.

Example

#include <GF2/GF2.h>
int main()
{
    GF2::Matrix<> m1("0000 0000 0000 0000");
    GF2::Matrix<> m2("0101 1010 0101 1010");
    GF2::Matrix<> m3("1111 1111 1111 1111");

    std::cout
        << "Matrix\t" << "count\t" << "diag\t" << "trace\n"
        << m1 << '\t' << m1.count() << '\t' << m1.count_diagonal() << '\t' << m1.trace() << '\n'
        << m2 << '\t' << m2.count() << '\t' << m2.count_diagonal() << '\t' << m2.trace() << '\n'
        << m3 << '\t' << m3.count() << '\t' << m3.count_diagonal() << '\t' << m3.trace() << '\n';
}

Output

Matrix  count   diag    trace
0000
0000
0000
0000    0       0       0
0101
1010
0101
1010    8       0       0
1111
1111
1111
1111    16      4       0

GF2::Matrix — Bit Counts

`GF2::Matrix` — Bit Counts