Variance of a collection of spectra

Method to compute the "parallel" variance of values across members of a collections of spectra or of a spectral object containing multiple spectra in long form.

Usage

s_var(x, na.rm, ...)

# Default S3 method
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'generic_spct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'filter_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'source_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'response_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'reflector_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'calibration_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'cps_mspct'
s_var(x, na.rm = FALSE, ...)

# S3 method for class 'raw_mspct'
s_var(x, na.rm = FALSE, ...)

Arguments

x: An R object.
na.rm: logical A value indicating whether NA values should be stripped before the computation proceeds.
...: Further arguments passed to or from other methods.

Value

If x is a collection spectral of objects, such as a "filter_mspct" object, the returned object belongs to the same class as the members of the collection, such as "filter_spct", containing the summary spectrum, with variables with names tagged for summaries other than mean or median.

Details

Method specializations compute the variance at each wavelength across a group of spectra stored in an object of one of the classes defined in package 'photobiology'. Omission of NAs is done separately at each wavelength. Interpolation is not applied, so all spectra in x must share the same set of wavelengths. An error is triggered if this condition is nor fulfilled.

Note

Objects of classes raw_spct and cps_spct can contain data from multiple scans in multiple variables or "columns". The parallel summaries' methods accept as arguments objects of these classes only if spectra contain data for a single spectrometer scan. In the case of cps_spct objects, a single column can also contain data from multiple scans spliced into a single variable.

Examples

s_var(sun_evening.mspct)
#> Object: generic_spct [1,593 x 2]
#> Wavelength range 290-1000 nm, step 0.34-0.47 nm 
#> Label: Variance for 5 source_spct objects.
#>  cosine.hour.9 
#> Measured on 2023-06-12 18:38:00.379657 UTC
#> Measured on 2023-06-12 18:39:00.797266 UTC
#> Measured on 2023-06-12 18:40:00.714554 UTC
#> Measured on 2023-06-12 18:41:00.768459 UTC
#> Measured on 2023-06-12 18:42:00.769065 UTC 
#> Measured at 60.227 N, 24.018 E; Viikki, Helsinki, FI 
#> Variables:
#>   
#> --
#> # A tibble: 1,593 × 2
#>    w.length s.e.irrad.var
#>       <dbl>         <dbl>
#>  1     290              0
#>  2     290.             0
#>  3     291.             0
#>  4     291.             0
#>  5     292.             0
#>  6     292.             0
#>  7     293.             0
#>  8     293.             0
#>  9     294.             0
#> 10     294.             0
#> # ℹ 1,583 more rows