The number parameter is a number
between 0 and 255,
defining to what extent the number of distinct
found words in a document affects its final score.
The default value is 0.
255 means maximum effect, 0 means that the number of distinct words does not affect the final score.
NumDistinctWordFactor has effect only when searching
for any word using the m=any search
parameter.
Search query consisting of multiple words will give more score to the
documents containing all of the search query words
and less score to the documents having only some of the words.