reformulate vs rehash

reformulate

verb
  • To formulate again or differently. 

rehash

verb
  • To repeat with minor variation. 

  • To analyze a prior contentious or embarrassing event. 

  • To hash (chop food into small pieces) again. 

  • To recompute the structure of a hash table, taking into account any newly added items. 

noun
  • A recomputation of the structure of a hash table, taking into account any newly added items. 

  • Something reworked, or made up from old materials. 

How often have the words reformulate and rehash occurred in a corpus of books? (source: Google Ngram Viewer )