1.0 - 8.00 - Sampling Arguments - Teradata Vantage

Teradata® Vantage Machine Learning Engine Analytic Function Reference

Product
Teradata Vantage
Release Number
1.0
8.00
Release Date
May 2019
Content Type
Programming Reference
Publication ID
B700-4003-098K
Language
English (United States)
SampleFraction
Specify one or more fractions to use in sampling the data. (Syntax options that do not use SampleFraction require ApproxSampleSize.)

If you specify only one fraction, then the function uses fraction for all strata defined by the sample conditions.

If you specify more than one fraction, then the function uses each fraction for sampling a particular stratum defined by the condition arguments.

For conditional sampling with variable sample sizes, specify one fraction for each condition that you specify with the Strata argument.
Seed
[Optional] Specify the random seed the algorithm uses for repeatable results. The seed must be a LONG value.
Default: 0
ApproxSampleSize
[Optional] Specify one or more approximate sample sizes to use in sampling the data. (Syntax options that do not use ApproxSampleSize require SampleFraction.) Each sample size is approximate because the function maps the size to the sample fractions and then creates the sample data.

If you specify only one size, it represents the total sample size for the entire population. If you also specify the Strata argument, the function proportionally creates sample units for each stratum.

If you specify more than one size, then each size corresponds to a stratum, and the function uses each size to create sample units for the corresponding stratum.

For conditional sampling with variable approximate sample sizes, specify one size for each condition that you specify with the Strata argument.
StratumColumn
[Required for conditional sampling, disallowed otherwise] Specify the name of the column that contains the sample conditions. If the function has only one input table (the data table), then stratum_column is in the data table. If the function has two input tables, data and summary, then stratum_column is in the summary table.
Strata
[Required with StratumColumn.] Specify the sample conditions that appear in the stratum_column. If Strata specifies a condition that does not appear in stratum_column, the function issues an error message.