jaydonnell · December 4, 2009 21:50
diff --git a/gistfile1.txt b/gistfile1.txt
 Yes sorry.

 Basically what we are trying is to constraint the effect of the raw frequency (saturate the frequency).
 In Lucene this is carried out with the root square of the frequency, another classical approach
 is to use the log. With both approaches we avoid giving a linear 'importance' to the frequency.

 BM25 is a bit tricky, it parametrises the 'saturation' of the frequency with a parameter k1, with the
 equation weight(t)/(weight(t)+k1). Usually k1 is fixed to 2, but it can be fixed by collection.
	Yes sorry.

	Basically what we are trying is to constraint the effect of the raw frequency (saturate the frequency).
	In Lucene this is carried out with the root square of the frequency, another classical approach
	is to use the log. With both approaches we avoid giving a linear 'importance' to the frequency.

	BM25 is a bit tricky, it parametrises the 'saturation' of the frequency with a parameter k1, with the
	equation weight(t)/(weight(t)+k1). Usually k1 is fixed to 2, but it can be fixed by collection.