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fold

stwo_gpu::core::poly::utils

Function fold 

Source 
pub fn fold<F: Field, E: ExtensionOf<F>>(
    values: &[F],
    folding_factors: &[E],
) -> E
Expand description

Folds values recursively in O(n) by a hierarchical application of folding factors.

i.e. folding n = 8 values with folding_factors = [x, y, z]:

              n2=n1+x*n2
          /               \
    n1=n3+y*n4          n2=n5+y*n6
     /      \            /      \
n3=a+z*b  n4=c+z*d  n5=e+z*f  n6=g+z*h
  /  \      /  \      /  \      /  \
 a    b    c    d    e    f    g    h

§Panics

Panics if the number of values is not a power of two or if an incorrect number of of folding factors is provided.