PolynomialExpansion
Related Docs:
class PolynomialExpansion
| package feature
Reads an ML instance from the input path, a shortcut of read.load(path).
Reads an ML instance from the input path, a shortcut of read.load(path).
Implementing classes should override this to be Java-friendly.
Returns an MLReader instance for this class.
Returns an MLReader instance for this class.
The expansion is done via recursion. Given n features and degree d, the size after expansion is (n + d choose d) (including 1 and first-order values). For example, let f([a, b, c], 3) be the function that expands [a, b, c] to their monomials of degree 3. We have the following recursion:
To handle sparsity, if c is zero, we can skip all monomials that contain it. We remember the current index and increment it properly for sparse input.