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- FilterFactory1d(filter_id=None, filter_type=None, window_type=None, filter_length=None, transition_bandwidth=None, low_cutoff=None, high_cutoff=None, sampling_frequency=None, filter_description=None, **generic_arguments)
- DESCRIPTION:
FilterFactory1d() function creates finite impulse response (FIR)
filter coefficients. The filters are based on certain parameters
and stored into a common table for reuse.
Note:
User needs EXECUTE PROCEDURE privelge on SYSLIB
PARAMETERS:
filter_id:
Required Argument.
Specifies the filter identifier, based on filter coefficients
stored in the table.
Types: int
filter_type:
Required Argument.
Specifies the type of filter to generate.
Permitted Values:
* LOWPASS - To remove frequencies above low_cutoff.
* HIGHPASS - To remove frequencies below high_cutoff.
* BANDPASS - To remove frequencies below low_cutoff and
above high_cutoff.
* BANDSTOP - To remove frequencies between low_cutoff
and high_cutoff.
Types: str
window_type:
Optional Argument.
Specifies the window function to the filter that maintains a
smooth drop-off to zero, and avoids extra artifacts in the
frequency domain. The default is to leave the filter
coefficients as they are, and not apply any windowing function.
Permitted Values: BLACKMAN, HAMMING, HANNING, BARTLETT
Types: str
filter_length:
Optional Argument.
Specifies the length of the filter to generate.
Overrides "transition_bandwidth" argument if both are supplied,
and renders the other an optional argument.
Default is approximately 4/("transition_bandwidth"/
"sampling_frequency").
Types: int
transition_bandwidth:
Optional Argument.
Specifies the maximum allowed size for the range of
frequencies for filter transitions between a passband and stopband.
This also determines the number of coefficients to be generated.
Value must be greater than 0.
A smaller value produces faster drop off at the cost of more coefficients.
Not used when "filter_length" is supplied.
Default is bandwidth from "filter_length".
Types: float
low_cutoff:
Optional Argument.
Specifies the lower frequency that change between a passband
and stopband occurs. It must be greater
than 0. It is not used by default with 'HIGHPASS' filter.
Types: float
high_cutoff:
Optional Argument.
Specifies the higher frequency that change
between a passband and stopband occurs. It must be greater
than 0 and not used by default with 'LOWPASS' filter.
Types: float
sampling_frequency:
Required Argument.
Specifies the frequency that the data to be filtered was
sampled. It must be greater than 0.
Types: float
filter_description:
Optional Argument.
Specifies the description for the filter coefficients
that contain the same filter ID. Description is only
written to one row for each filter generated, and
ROW_I is 0. Default is a string describing parameters.
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
RAISES:
TeradataMlException, TypeError, ValueError
EXAMPLES:
# Notes:
# 1. Get the connection to Vantage, before importing the
# function in user space.
# 2. User can import the function, if it is available on
# Vantage user is connected to.
# 3. To check the list of UAF analytic functions available
# on Vantage user connected to, use
# "display_analytic_functions()".
# Check the list of available UAF analytic functions.
display_analytic_functions(type="UAF")
# Import function FilterFactory1d.
from teradataml import FilterFactory1d
# Example 1: Create finite impulse response (FIR) filter coefficients.
res = FilterFactory1d(filter_id = 33,
filter_type = 'lowpass',
window_type = 'blackman',
transition_bandwidth = 20.0,
low_cutoff = 40.0,
sampling_frequency = 200)
print(res.result)
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