pub fn decode_shift(index: usize) -> (ShiftVariant, usize)Expand description
The (variant, amount) pair a shift index names.
This inverts Shift::index over the reduction’s
index space rather than over well-formed shifts: the amount axis spans Word::BITS for every
variant, so a half-word (*32) variant’s index may carry an amount no Shift of that variant
could hold. Such an index is a hypercube vertex the sumcheck ranges over all the same.
§Panics
Panics unless the index is below [SHIFT_COUNT].