src/ports/postgres/modules/utilities/mean_std_dev_calculator.py_in

# coding=utf-8
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"""
@file mean_std_dev_calculator.py_in

@brief

@namespace utilities

"""
import plpy
from convex.utils_regularization import utils_ind_var_scales
from convex.utils_regularization import utils_ind_var_scales_grouping
from utilities import _array_to_string

m4_changequote(`<!', `!>')

#TODO: use this for all the modules that calculate the std dev and mean for x
# mlp, pca, elastic_net
class MeanStdDevCalculator:
    def __init__(self, schema_madlib, source_table, indep_var_array_str, dimension):
        self.schema_madlib= schema_madlib
        self.source_table= source_table
        self.indep_var_array_str = indep_var_array_str
        self.dimension = dimension

    def get_mean_and_std_dev_for_ind_var(self):
        x_scaled_vals = utils_ind_var_scales(self.source_table,
                                             self.indep_var_array_str,
                                             self.dimension,
                                             self.schema_madlib,
                                             x_mean_table = None, # do not dump the output to a temp table
                                             set_zero_std_to_one=True)
        x_mean_str = _array_to_string(x_scaled_vals["mean"])
        x_std_str = _array_to_string(x_scaled_vals["std"])

        if not x_mean_str or not x_std_str:
            plpy.error("mean/stddev for the independent variable"
                       "cannot be null")

        return x_mean_str, x_std_str

    def create_mean_std_table_for_ind_var_grouping(self, x_mean_table, grouping_cols):
        utils_ind_var_scales_grouping(self.source_table,
                                      self.indep_var_array_str,
                                      self.dimension,
                                      self.schema_madlib,
                                      grouping_cols,
                                      x_mean_table,
                                      set_zero_std_to_one = True,
                                      create_temp_table = False)