TD_DFFT2 Syntax Elements - Teradata Vantage

Database Unbounded Array Framework Time Series Functions
Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2024-10-04
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MATRIX_SPEC
The two-dimensional matrix that is passed to the TD_DFFT2 function.
Name Description
MATRIX_SPEC(CONTENT(REAL)) A matrix containing real number elements.
MATRIX _SPEC(CONTENT(COMPLEX)) A matrix containing complex number elements.
MATRIX _SPEC(CONTENT(MULTIVAR_REAL)) A multivariate matrix containing more than one real number elements.
MATRIX _SPEC(CONTENT(MULTIVAR_COMPLEX)) A multivariate matrix containing more than one complex number elements.

See Matrix Specifications.

ART_SPEC
An ART that contains the two-dimensional matrix that is passed to the TD_DFFT2 function.

See ART_SPEC Syntax Elements

FUNC_PARAMS
Name Data Type Description
ZERO_PADDING_OK Integer [Optional] Indicator to add zeros to the end of a given series to achieve a more efficient computation of the fast Fourier transform (FFT) coefficients. A value of 1 means true, and a value of 0 means false. The default is 1.
FREQ_STYLE String [Optional] The format or values associated with the x-axis of the output. Choices are as follows:
  • K_INTEGRAL: Integer representation.
  • K_SAMPLE_RATE: Integer normalized to number entries, with ranges from -0.5 to +0.5.
  • K_RADIANS: Radian ranges from -π to +π.
  • K_HERTZ: Frequency in hertz. Must be used in conjunction with HERTZ_SAMPLE_RATE.

The default is K_INTEGRAL.
HERTZ_SAMPLE_RATE FLOAT [Dependencies: Only used and required with the FREQ_STYLE(K_HERTZ) parameter.] The sample rate as a floating point constant, in hertz. A value of 10000.0 indicates that the sample points were obtained by sampling at a rate of 10,000 hertz. This hertz interpretation applies to both the ROW_I and COLUMN_I indices.
ALGORITHM String [Optional] The user-defined algorithm that bypasses the internal DFFT2 planner and influences the core DFFT2 algorithm associated with the primary DFFT2 calculation.

Options are COOLEY_TUKEY, or SINGLETON.

The default when this parameter is not present is that the internal DFFT planner selects the most efficient algorithm for the operation.
HUMAN_READABLE Integer [Optional] Indicator to produce output rows of the matrix in human-readable or plottable form, or the output is in the raw-form. Human-readable output is symmetric around 0, such as -3, -2, -1, 0, 1, 2, 3. Raw output is sequential, starting at zero, such as 0, 1, 2, 3.

A value of 1 means the output is in human readable form. A value of 0 means the output is in raw form. The default is 1.
INPUT_FMT
No INPUT_FMT options are available for this function.
OUTPUT_FMT

A complex number that can be in rectangular (real, imaginary) or polar (amplitude, phase) form. The output options for univariate series are the following:

  • COMPLEX
  • AMPL_PHASE_DEGREES
  • AMPL_PHASE_RADIANS

The default is COMPLEX.

The OUTPUT_FMT CONTENT output for multivariate series are the following:
  • MULTIVAR_COMPLEX
  • MULTIVAR_AMPL_PHASE_DEGREES
  • MULTIVAR_AMPL_PHASE_RADIANS
  • MULTIVAR_AMPL_PHASE

The default is MULTIVAR_COMPLEX.