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- HoltWintersForecaster(data=None, data_filter_expr=None, forecast_periods=None, alpha=None, beta=None, gamma=None, seasonal_periods=None, init_level=None, init_trend=None, init_season=None, model=None, fit_percentage=100, prediction_intervals='BOTH', fit_metrics=False, selection_metrics=False, residuals=False, output_fmt_index_style='NUMERICAL_SEQUENCE', **generic_arguments)
- DESCRIPTION:
The HoltWintersForecaster() function uses triple exponential smoothing
on a forecast model with seasonal data.
PARAMETERS:
data:
Required Argument.
Specifies the time series to forecast using historical data
with series content type as 'REAL' or 'MULTIVAR_REAL'.
Types: TDSeries
data_filter_expr:
Optional Argument.
Specifies the filter expression for "data".
Types: ColumnExpression
forecast_periods:
Required Argument.
Specifies the number of periods to forecast.
Value must be greater than or equal to 1.
Types: int
alpha:
Optional Argument.
Specifies a value to control the smoothing relative to
the level component of the forecasting equation. If
specified, this value is used in the equation to perform
the forecasting, else the "alpha" value is estimated using
goodness-of-fit metrics. Value must be greater than or equal
to 0 and less than or equal to 1.
Types: float
beta:
Optional Argument.
Specifies a value to control the smoothing relative to
the trend component of the forecasting equation. If
specified, this value is used in the equation to perform
the forecasting, else the "beta" value is estimated using
goodness-of-fit metrics. Value must be greater than or equal
to 0 and less than or equal to 1.
Types: float
gamma:
Optional Argument.
Specifies a value to control the smoothing relative to
the seasonal component of the forecasting equation. If
specified, this value is used in the equation to perform
the forecasting, else the "gamma" value is estimated using
goodness-of-fit metrics. Value must be greater than or equal
to 0 and less than or equal to 1.
Types: float
seasonal_periods:
Optional Argument.
Specifies the number of periods or sample points for one season.
For example, for yearly data with monthly sample points, the parameter
is 12; and for quarterly data with monthly sample points, the
parameter is 3. Value must be greater than or equal to 1.
Note:
Required when "gamma" or "init_season" is specified.
Types: int
init_level:
Optional Argument.
Specifies the initialization value used as part of the fitting
and forecasting operations. If not specified, then the initialization
value is calculated as an additive level.
Types: float
init_trend:
Optional Argument.
Specifies the initialization value used as part of the fitting
and forecasting operations. If not specified, then the initialization
value is calculated as an additive trend.
Types: float
init_season:
Optional Argument.
Specifies a list of initialization values, one per period. If
specified, the initialization value is used as part of the
fitting and forecasting operations, else the initialization
value is calculated as a multiplicative seasonality.
Types: float, list of float
model:
Required Argument.
Specifies the type of Holt Winters forecasting.
Permitted Values:
* ADDITIVE: It is based on Holt Winters Additive approach.
* MULTIPLICATIVE: It is based on Holt Winters Multiplicative approach.
Types: str
fit_percentage:
Optional Argument.
Specifies percentage of passed-in sample points to use for the
model fitting or parameter estimation. Value must be greater
than or equal to 0 and less than or equal to 100.
Default Value: 100
Types: int
prediction_intervals:
Optional Argument.
Specifies the confidence level for the prediction.
Permitted Values:
* NONE
* 80
* 95
* BOTH
Default Value: BOTH
Types: str
fit_metrics:
Optional Argument.
Specifies whether to generate the result set that contains the
model metadata statistics. When set to True, function generates
the model statistics, otherwise not. The generated model
statistics can be retrieved using the attribute "fitmetadata"
of the function output.
Default Value: False
Types: bool
selection_metrics:
Optional Argument.
Specifies whether to generate the result set that contains the
selection metrics. When set to True, function generates the
selection metrics, otherwise not. The generated selection metrics
can be retrieved using the attribute "selmetrics" of the function
output.
Default Value: False
Types: bool
residuals:
Optional Argument.
Specifies whether to generate the result set that contains the
model residuals. When set to True, the function generates the
residuals, otherwise not. The generated residuals can be retrieved
using the attribute "fitresiduals" of the function output.
Default Value: False
Types: bool
output_fmt_index_style:
Optional Argument.
Specifies the index style of the output format.
Permitted Values:
* NUMERICAL_SEQUENCE
* FLOW_THROUGH
Default Value: NUMERICAL_SEQUENCE
Types: str
**generic_arguments:
Specifies the generic keyword arguments of UAF functions.
Below are the generic keyword arguments:
persist:
Optional Argument.
Specifies whether to persist the results of the
function in a table or not. When set to True,
results are persisted in a table; otherwise,
results are garbage collected at the end of the
session.
Note that, when UAF function is executed, an
analytic result table (ART) is created.
Default Value: False
Types: bool
volatile:
Optional Argument.
Specifies whether to put the results of the
function in a volatile ART or not. When set to
True, results are stored in a volatile ART,
otherwise not.
Default Value: False
Types: bool
output_table_name:
Optional Argument.
Specifies the name of the table to store results.
If not specified, a unique table name is internally
generated.
Types: str
output_db_name:
Optional Argument.
Specifies the name of the database to create output
table into. If not specified, table is created into
database specified by the user at the time of context
creation or configuration parameter. Argument is ignored,
if "output_table_name" is not specified.
Types: str
RETURNS:
Instance of HoltWintersForecaster.
Output teradataml DataFrames can be accessed using attribute
references, such as HoltWintersForecaster_obj.<attribute_name>.
Output teradataml DataFrame attribute names are:
1. result
2. fitmetadata - Available when "fit_metrics" is set to True, otherwise not.
3. selmetrics - Available when "selection_metrics" is set to True, otherwise not.
4. fitresiduals - Available when "residuals" is set to True, otherwise not.
RAISES:
TeradataMlException, TypeError, ValueError
EXAMPLES:
# Notes:
# 1. Get the connection to Vantage to execute the function.
# 2. One must import the required functions mentioned in
# the example from teradataml.
# 3. Function will raise error if not supported on the Vantage
# user is connected to.
# Check the list of available UAF analytic functions.
display_analytic_functions(type="UAF")
# Load the example data.
load_example_data("uaf", ["us_air_pass"])
# Create teradataml DataFrame object.
data = DataFrame.from_table("us_air_pass")
# Create teradataml TDSeries object.
data_series_df = TDSeries(data=data,
row_index="idx",
row_index_style="SEQUENCE",
id="id",
payload_field="international",
payload_content="REAL")
# Example 1: Generate forecast for 12 periods using multiplicative model.
uaf_out = HoltWintersForecaster(data=data_series_df,
forecast_periods=12,
model="MULTIPLICATIVE",
residuals=True,
fit_metrics=True,
selection_metrics=True)
# Print the result DataFrames.
print(uaf_out.result)
# Print the model statistics result.
print(uaf_out.fitmetadata)
# Print the selection metrics result.
print(uaf_out.selmetrics)
# Print the residuals statistics result.
print(uaf_out.fitresiduals)
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