Efficient comparison of 100.000 vectors

Question

I save 100.000 Vectors of in a database. Each vector has a dimension 60. (int vector[60])

Then I take one and want present vectors to the user in order of decreasing sim

Answer 1

So the following information can be cached:

• Norm of the chosen vector
• The dot product A.B, reusing it for both the numerator and the denominator in a given T(A,B) calculation.

If you only need the N closest vectors or if you are doing this same sorting process multiple times, there may be further tricks available. (Observations like T(A,B)=T(B,A), caching the vector norms for all the vectors, and perhaps some sort of thresholding/spatial sort).