fn toom3(acc: &mut [u64], x: &[u64], y: &[u64])Expand description
Toom-3 multiplication:
Toom-3 is like Karatsuba above, but dividing the inputs into three parts.
Both are instances of Toom-Cook, using k=3 and k=2 respectively.
The general idea is to treat the large integers digits as polynomials of a certain degree and determine the coefficients/digits of the product of the two via interpolation of the polynomial product.