Photon:photon ratio
This function returns the photon ratio for a given pair of wavebands of a light source spectrum.
q_ratio(
spct,
w.band.num,
w.band.denom,
scale.factor,
wb.trim,
use.cached.mult,
use.hinges,
...
)
## Default S3 method:
q_ratio(
spct,
w.band.num,
w.band.denom,
scale.factor,
wb.trim,
use.cached.mult,
use.hinges,
...
)
## S3 method for class '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 class '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
)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
|
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 |
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. |
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.
default: Default for generic function
source_spct: Method for source_spct objects
source_mspct: Calculates photon:photon from a source_mspct
object.
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.
q_ratio(sun.spct, new_waveband(400,500), new_waveband(400,700))
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