Python Evaluator

Creates a Python Evaluator,

that executes a Python function provided by the user on a DataFrame connected to its input port. Returns the result metric of the execution as a MetricValue.

The Python function that will be executed must:

• be named evaluate,

• take exactly one argument of type DataFrame,

• return a float.

This operation has an is larger better that indicates whether the returned metric is better to be maximized or minimized. It is especially useful in Grid Search operation that searches for the best Estimator using a given metric.

Example Python code:

from math import sqrt
from operator import add

def evaluate(dataframe):
    # Example Root-Mean-Square Error implementation
    n = dataframe.count()
    row_to_sq_error = lambda row: (row['label'] - row['prediction'])**2
    sum_sq_error = dataframe.map(row_to_sq_error).reduce(add)
    rmse = sqrt(sum_sq_error / n)
    return rmse

Since: Seahorse 1.2.0

Input

This operation does not take any input.

Output

Parameters