massive_variance_test

hana_ml.algorithms.pal.preprocessing.massive_variance_test(data, sigma_num, group_key=None, thread_ratio=None, key=None, data_col=None)

Massive version of variance_test().

This function calls SAP HANA PAL function PAL_MASSIVE_VARIANCE_TEST to run variance test in parallel across multiple independent datasets identified by a group id.

Parameters
dataDataFrame

Input data for variance test in massive mode.

This DataFrame must be structured as follows:

  • 1st column : GROUP ID, type INT, VARCHAR or NVARCHAR.

  • 2nd column : ID, type INT, VARCHAR or NVARCHAR.

  • 3rd column : raw data, type INTEGER, DOUBLE, or DECIMAL(p,s).

sigma_numfloat

Multiplier for sigma.

group_keystr, optional

Name of the group id column. If not provided, it defaults to:

  • the first index column of data if data is indexed, otherwise

  • the first column of data.

thread_ratiofloat, optional

Same meaning as in variance_test().

keystr, optional

Name of the ID column in data.

If not specified, it defaults to:

  • the second index column of data if data has multiple index columns and the first one is used as group_key, otherwise

  • the first non-group_key column of data.

data_colstr, optional

Name of the raw data column in the dataframe.

If not specified, defaults to the last column of data excluding group_key and key.

Returns
DataFrames

DataFrame 1 : result output with an additional group id column.

DataFrame 2 : statistics output with an additional group id column.

DataFrame 3 : error message table for massive execution.