`bit::matrix` — Logical Shift Operators

Methods to perform binary left and right shifts on the rows in a bit-matrix.

1constexpr bit::matrix &operator<<=(std::size_t p);
2constexpr bit::matrix &operator>>=(std::size_t p);

3constexpr bit::matrix operator<<(std::size_t p) const;
4constexpr bit::matrix operator>>(std::size_t p) const;

1: Left-shift the rows in this bit-matrix p places with zeros shifted in as needed.
2: Right-shift the rows in this bit-matrix p places with zeros shifted in as needed.
3: Returns a bit-matrix that is this one with its rows left shifted by p places
4: Returns a bit-matrix that is this one with its rows right shifted by p places

The first two methods are destructive (i.e., operate in-place) and return a reference to *this so they can be chained with other calls.

Shifts in the bit library work in vector-order so if a row is [e0, e1, e2, e3] then a left shift turns that into [e1, e2, e3, 0] and a right shift turns it into [0, e0, e1, e2]. Vector-order shifts are the opposite of bit-order shifts!

Example

#include <bit/bit.h>
int
main()
{
    auto m = bit::matrix<>::ones(4,4);
    std::cout << "Left shift:\n";
    std::cout << "m:     \n" << m          << '\n';
    std::cout << "m << 1:\n" << ((m << 1)) << '\n';
    std::cout << "m << 3:\n" << ((m << 3)) << '\n';
    std::cout << "m << 5:\n" << ((m << 5)) << '\n';

    std::cout << "Right shift:\n";
    std::cout << "m:     \n" << m          << '\n';
    std::cout << "m >> 1:\n" << ((m >> 1)) << '\n';
    std::cout << "m >> 3:\n" << ((m >> 3)) << '\n';
    std::cout << "m >> 5:\n" << ((m >> 5)) << '\n';
}

Output

Left shift:
m:
│1 1 1 1│
│1 1 1 1│
│1 1 1 1│
│1 1 1 1│
m << 1:
│1 1 1 0│
│1 1 1 0│
│1 1 1 0│
│1 1 1 0│
m << 3:
│1 0 0 0│
│1 0 0 0│
│1 0 0 0│
│1 0 0 0│
m << 5:
│0 0 0 0│
│0 0 0 0│
│0 0 0 0│
│0 0 0 0│

Right shift:
m:
│1 1 1 1│
│1 1 1 1│
│1 1 1 1│
│1 1 1 1│
m >> 1:
│0 1 1 1│
│0 1 1 1│
│0 1 1 1│
│0 1 1 1│
m >> 3:
│0 0 0 1│
│0 0 0 1│
│0 0 0 1│
│0 0 0 1│
m >> 5:
│0 0 0 0│
│0 0 0 0│
│0 0 0 0│
│0 0 0 0│

See Also