TD_DFFT2 Syntax Elements - Teradata Vantage

Database Unbounded Array Framework Time Series Functions
Deployment
VantageCloud
VantageCore
Edition
VMware
Enterprise
IntelliFlex
Product
Teradata Vantage
Release Number
17.20
Published
June 2022
ft:locale
en-US
ft:lastEdition
2025-04-04
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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.