Filter: Filter Frequency Peaks From An Array

In s2dverification: Set of Common Tools for Forecast Verification

Filter Frequency Peaks From An Array

Description

This function filters out the selected frequency from a time series.
The filtering is performed by dichotomy, seeking for a frequency around the parameter freq and the phase that maximizes the signal to subtract from the time series.
The maximization of the signal to subtract relies on a minimization of the mean square differences between the time series (xdata) and the cosine of the specified frequency and phase.

Usage

Filter(xdata, freq)

Arguments

xdata	Array to be filtered.
freq	Frequency to filter.

Value

Filtered Array.

Author(s)

History:
0.1 - 2012-02 (V. Guemas) - Original code
1.0 - 2012-02 (N. Manubens) - Formatting to CRAN

Examples

# Load sample data as in Load() example:
example(Load)
ensmod <- Mean1Dim(sampleData$mod, 2)
for (jstartdate in 1:3) {
 spectrum <- Spectrum(ensmod[1, jstartdate, ])
 for (jlen in 1:dim(spectrum)[1]) {
   if (spectrum[jlen, 2] > spectrum[jlen, 4]) {
     ensmod[1, jstartdate, ] <- Filter(ensmod[1, jstartdate, ], 
                                       spectrum[jlen, 1])
   }
 }
}
 
PlotAno(InsertDim(ensmod, 2, 1), sdates = startDates, fileout =
       'filtered_ensemble_mean.eps') 
 

s2dverification documentation built on April 20, 2022, 9:06 a.m.