Function q1tsim::gates::bit_permutation

pub fn bit_permutation(nr_bits: usize, affected_bits: &[usize]) -> Permutation

Reorder bits.

When applying multi-bit gates, the rows in the state are shuffled such that:

• The first half of the rows correspond to components with the first affected bit being 0, the second half to those with this bit being 1.
• Within each of these two blocks, the first half corresponds to components with the second bit 0, the second half to those with the second bit 1.
• And so on, for each affected bit.

This function returns a permutation matrix P, such that the matrix P (G ⊗ I ⊗ ... ⊗ I) PT describes the effect of operating with a gate G on bits affected_bits in a nr_bits-sized system.