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Correct signature size calculation #14

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Correct signature size calculation #14

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snie2012
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@snie2012 snie2012 commented Aug 7, 2017 •
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According to the description in this file, signature size equals to R * b instead of R * s

@snie2012
Correct signature size calculation
5a3f4b8 
According to the description in this file, signature size equals to R * b instead of R * n
snie2012
snie2012 commented Aug 7, 2017
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src/main/java/info/debatty/java/lsh/LSHMinHash.java
@@ -66,7 +66,7 @@ public LSHMinHash(final int s, final int b, final int n) {
*/
public LSHMinHash(final int s, final int b, final int n, final long seed) {
super(s, b);
int signature_size = computeSignatureSize(s, n);
int signature_size = computeSignatureSize(s, b);
this.mh = new MinHash(signature_size, n, seed);
}

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The parameter should be changed to b as well.

@tdebatty
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Hi,
I should check this very carefully, because I don't use the same notation as in the book:

  • the book calls bands (b) what I in the code call stages (s)
  • in the code b stands for buckets (per stage)

@snie2012
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snie2012 commented Aug 12, 2017 •
edited

Hi, I checked again based on your comment. It looks like my correction is wrong. Inside the computeSignatureSize function, r is the number of rows and s is the number of bands, so the signature size should be r * s. Please confirm! (The notations in the comments above the function are a little bit confusing, you might want to change that.)

By the way, the parameter n passed to computeSignatureSize is not used. Is this for consistency?

@tavish
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tavish commented Jan 14, 2019

I also had a question about the parameter n not being used in computeSignatureSize.

@tdebatty, could you comment on this please? Thank you, in advance.

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@snie2012 @tdebatty @tavish