Function field_parallel_crossover 

pub fn field_parallel_crossover() -> usize

The element count at or above which multi-threading is worth its overhead for the field-algebra kernels.

Returns FIELD_PARALLEL_CROSSOVER — the measured field-kernel crossover, deliberately overriding the documented placeholder crate::compute::CPU_MULTI_MIN_WORK_ITEMS (see that constant’s docs for why the override exists and the numbers behind it).

It is a function, not a bare constant, so the policy can later consult a runtime-configured value without touching a single operator.

Units: a count of field elements — cells for a volume field, internal faces for a surface field. Dimensionless.