Description
The IDWT2D function is the inverse of DWT2D. IDWT2D applies
inverse wavelet transforms on multiple sequences simultaneously.
IDWT2D takes as input the output tbl_teradata and meta tbl_teradata
generated by function DWT2D (td_dwt2d_mle
) and outputs the sequences as 2-dimensional
matrices. Because the IDWT2D output is comparable to the DWT2D
input, the inverse transformation is also called the reconstruction.
Usage
td_idwt2d_mle (
meta.table = NULL,
coefficient = NULL,
input.columns = NULL,
sort.column = NULL,
compact.output = TRUE,
partition.columns = NULL,
coefficient.sequence.column = NULL,
meta.table.sequence.column = NULL
)
Arguments
meta.table |
Required Argument. |
coefficient |
Required Argument. |
input.columns |
Required Argument. |
sort.column |
Required Argument. |
compact.output |
Optional Argument. |
partition.columns |
Optional Argument. |
coefficient.sequence.column |
Optional Argument. |
meta.table.sequence.column |
Optional Argument. |
Value
Function returns an object of class "td_idwt2d_mle" which is a named
list containing objects of class "tbl_teradata".
Named list members can be referenced directly with the "$" operator
using following names:
output.table
output
Examples
# Get the current context/connection
con <- td_get_context()$connection
# Load example data.
# dataset contains climate data in cities in California (CA), Texas (TX), and Washington (WA).
# The cities are represented by two-dimensional coordinates (latitude and longitude).
# The data are temperature (in degrees Fahrenheit), pressure (in Mbars),
# and dew point (in degrees Fahrenheit).
loadExampleData("dwt2d_example", "twod_climate_data")
# Create object(s) of class "tbl_teradata".
twod_climate_data <- tbl(con, "twod_climate_data")
# Example 1 - The function outputs a coefficient model tbl_teradata and a meta tbl_teradata.
td_dwt2d_out <- td_dwt2d_mle(data = twod_climate_data,
input.columns = c("temp_f","pressure_mbar","dewpoint_f"),
index.columns = c("latitude","longitude"),
wavelet = "db2",
level = 2,
compact.output = TRUE,
partition.columns = c("state")
)
# Consume output of td_dwt2d_mle() and output the sequences.
td_idwt2d_out <- td_idwt2d_mle(meta.table = td_dwt2d_out$meta.table,
coefficient = td_dwt2d_out$coefficient,
input.columns = c("temp_f","pressure_mbar","dewpoint_f"),
sort.column = "waveletid",
partition.columns = c("state")
)