Description

Polynomial expansion is the process of expanding your features into a polynomial space, which is formulated by an n-degree combination of original dimensions. Take a 2-variable feature vector as an example: (x, y), if we want to expand it with degree 2, then we get (x, x x, y, x y, y * y).

Parameters

Name Description Type Required？ Default Value
degree degree of polynomial expand. Integer 2
selectedCol Name of the selected column used for processing String ✓
outputCol Name of the output column String null
reservedCols Names of the columns to be retained in the output table String[] null

Script Example

Script

  1. data = np.array([["$8$1:3,2:4,4:7"],
  2.     ["$8$2:4,4:5"]])
  3. df = pd.DataFrame({"vec" : data[:,0]})
  4. data = dataframeToOperator(df, schemaStr="vec string",op_type="batch")
  5. VectorPolynomialExpandBatchOp().setSelectedCol("vec").setOutputCol("vec_out").linkFrom(data).collectToDataframe()

Result

vec vec_out
$8$1:3,2:4,4:7 $44$2:3.0 4:9.0 5:4.0 7:12.0 8:16.0 14:7.0 16:21.0 17:28.0 19:49.0
$8$2:4,4:5 $44$5:4.0 8:16.0 14:5.0 17:20.0 19:25.0