genharmonic {miscFuncs}

genharmonic function

Description

A function to create harmonic terms ready for a harmonic regression model to be fitted.

Usage

genharmonic(
  df,
  tname,
  base,
  num,
  sinfun = sin,
  cosfun = cos,
  sname = "s",
  cname = "c",
  power = FALSE
)

Arguments

df

a data frame

tname

a character string, the name of the time variable. Note this variable will be converted using the function as.numeric

base

the period of the first harmonic e.g. for harmonics at the sub-weekly level, one might set base=7 if time is measured in days

num

the number of harmonic terms to return

sinfun

function to compute sin-like components in model. Default is sin, but alternatives include sintri, or any other periodic function defined on [0,2pi]

cosfun

function to compute sin-like components in model. Default is cos, but alternatives include costri, or any other periodic function defined on [0,2pi] offset to sinfun by pi/2

sname

the prefix of the sin terms, default 's' returns variables 's1', 's2', 's3' etc.

cname

the prefix of the cos terms, default 's' returns variables 's1', 's2', 's3' etc.

power

logical, if FALSE (the default) it will return the standard Fourier series with sub-harmonics at 1, 1/2, 1/3, 1/4 of the base periodicicy. If TRUE, a power series will be used instead, with harmonics 1, 1/2, 1/4, 1/8 etc. of the base frequency.

Value

a data frame with the time variable in numeric form and the harmonic components