R/selectHalfWidth.R

In xemd: eXtended Empirical Mode Decomposition

# Adapted from fifpy, revision 26e51e7d45e551950dea8be37ece447fc4340296.
# SPDX-License-Identifier: MIT
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# Copyright (c) 2022 Emanuele Papini
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# Half width l of the filter of one IF extraction, in samples, proportional to
# N / E for the E extrema of the residue and fixed during the extraction
# (lmd.model:232, 244), by the rule 'ave' of fifpy get_mask_length:
# l = 2 round(stretch N / E). From the second extraction, a value that does
# not exceed the previous half width becomes ceiling(1.1 previous), with the
# product formed in double precision as in fifpy. previous is NULL in the
# first extraction.
.selectHalfWidth <- function(extremaCount, sampleCount, stretch, previous) {
    HalfWidth <- 2 * round(sampleCount / extremaCount * stretch)
    if (!is.null(previous) && HalfWidth <= previous) HalfWidth <- ceiling(previous * 1.1)
    as.integer(HalfWidth)
}