e_ratio: Energy:energy ratio

Description Usage Arguments Value Methods (by class) Note See Also Examples

View source: R/spct.ratios.R

Description

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

Usage

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e_ratio(spct, w.band.num, w.band.denom, wb.trim, use.cached.mult, use.hinges,
  ...)

## Default S3 method:
e_ratio(spct, w.band.num, w.band.denom, wb.trim,
  use.cached.mult, use.hinges, ...)

## S3 method for class 'source_spct'
e_ratio(spct, w.band.num = NULL, w.band.denom = NULL,
  wb.trim = getOption("photobiology.waveband.trim", default = TRUE),
  use.cached.mult = FALSE,
  use.hinges = getOption("photobiology.use.hinges"), ...)

## S3 method for class 'source_mspct'
e_ratio(spct, w.band.num = NULL, w.band.denom = NULL,
  wb.trim = getOption("photobiology.waveband.trim", default = TRUE),
  use.cached.mult = FALSE,
  use.hinges = getOption("photobiology.use.hinges"), ..., attr2tb = NULL,
  idx = !is.null(names(spct)), .parallel = FALSE, .paropts = NULL)

Arguments

spct

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).

wb.trim

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

use.cached.mult

logical Flag telling 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 used by derived methods).

attr2tb

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

idx

logical whether to add a column with the names of the elements of spct

.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 energy ratio between integrated energy 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 "(e:e)" 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)

Note

Recycling for wavebands takes place when the number of denominator and denominator wavebands differ. The last two parameters control speed optimizations. The defaults should be suitable in most cases. If you will use repeatedly the same SWFs on many spectra measured at exactly the same wavelengths you may obtain some speed up by setting use.cached.mult=TRUE. However, be aware that you are responsible for ensuring that the wavelengths are the same in each call, as the only test done is for the length of the w.length vector.

See Also

Other photon and energy ratio functions: eq_ratio, q_ratio, qe_ratio

Examples

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photobiology documentation built on April 3, 2018, 1:06 a.m.