Sets the fraction of hash bins to be reorganized. The number you enter will be the denominator of a fraction with a numerator of 1 (e.g., setting this keyword to 4 results in a fraction of 1/4, so one fourth of the hash bins are reorganized.
PREIMAGE_HASH_REHASHFAC <fraction of hash bins reorganized>
Default: 4 (denominator - one fourth at a time)