photobiology (version 0.10.6)

q_ratio: Photon:photon ratio

Description

This function returns the photon ratio for a given pair of wavebands of a light source spectrum.

Usage

q_ratio(
  spct,
  w.band.num,
  w.band.denom,
  scale.factor,
  wb.trim,
  use.cached.mult,
  use.hinges,
  ...
)
# S3 method for default
q_ratio(
  spct,
  w.band.num,
  w.band.denom,
  scale.factor,
  wb.trim,
  use.cached.mult,
  use.hinges,
  ...
)
# S3 method for source_spct
q_ratio(
  spct,
  w.band.num = NULL,
  w.band.denom = NULL,
  scale.factor = 1,
  wb.trim = getOption("photobiology.waveband.trim", default = TRUE),
  use.cached.mult = FALSE,
  use.hinges = NULL,
  naming = "short",
  name.tag = ifelse(naming != "none", "[q:q]", ""),
  ...
)
# S3 method for source_mspct
q_ratio(
  spct,
  w.band.num = NULL,
  w.band.denom = NULL,
  scale.factor = 1,
  wb.trim = getOption("photobiology.waveband.trim", default = TRUE),
  use.cached.mult = FALSE,
  use.hinges = NULL,
  naming = "short",
  name.tag = ifelse(naming != "none", "[q:q]", ""),
  ...,
  attr2tb = NULL,
  idx = "spct.idx",
  .parallel = FALSE,
  .paropts = NULL
)

Arguments

spct

an object of class "source_spct".

w.band.num

waveband object or a list of waveband objects used to compute the numerator(s) of the ratio(s).

w.band.denom

waveband object or a list of waveband objects used to compute the denominator(s) of the ratio(s).

scale.factor

numeric vector of length 1, or length equal to that of w.band. Numeric multiplier applied to returned values.

wb.trim

logical if TRUE wavebands crossing spectral data boundaries are trimmed, if FALSE, they are discarded

use.cached.mult

logical indicating whether multiplier values should be cached between calls

use.hinges

logical Flag indicating whether to insert "hinges" into the spectral data before integration so as to reduce interpolation errors at the boundaries of the wavebands.

...

other arguments (possibly ignored)

naming

character one of "long", "default", "short" or "none". Used to select the type of names to assign to returned value.

name.tag

character Used to tag the name of the returned values.

attr2tb

character vector, see add_attr2tb for the syntax for attr2tb passed as is to formal parameter col.names.

idx

character Name of the column with the names of the members of the collection of spectra.

.parallel

if TRUE, apply function in parallel, using parallel backend provided by foreach

.paropts

a list of additional options passed into the foreach function when parallel computation is enabled. This is important if (for example) your code relies on external data or packages: use the .export and .packages arguments to supply them so that all cluster nodes have the correct environment set up for computing.

Value

In the case of methods for individual spectra, a numeric vector of adimensional values giving a photon ratio between integrated photon irradiances for pairs of wavebands, with name attribute set to the name of the wavebands unless a named list of wavebands is supplied in which case the names of the list elements are used, with "(q:q)" appended. A data.frame in the case of collections of spectra, containing one column for each ratio definition, an index column with the names of the spectra, and optionally additional columns with metadata values retrieved from the attributes of the member spectra.

Ratio definitions are "assembled" from the arguments passed to w.band.num and w.band.denom. If both arguments are of equal length, then the wavebands are paired to obtain as many ratios as the number of wavebands in each list. Recycling for wavebands takes place when the number of denominator and numerator wavebands differ.

Methods (by class)

• default: Default for generic function

• source_spct: Method for source_spct objects

• source_mspct: Calculates photon:photon from a source_mspct object.

See Also

Other photon and energy ratio functions: e_ratio(), eq_ratio(), qe_ratio()

Examples

# NOT RUN {
q_ratio(sun.spct, new_waveband(400,500), new_waveband(400,700))

# }