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Lowpass Filter

Source: R/lowpass.R
lowpass.Rd

Filters high frequencies out of a time series. The filter has the structure `x'(n) = (x(n-1)+2*x(n)+x(n+1))/4`

Usage

lowpass(x, i = 1, fix = NULL, altFilter = NULL, warn = TRUE)

Arguments

x

Vector of data points, that should be filtered or MAgPIE object

i

number of iterations the filter should be applied to the data

fix

Fixes the starting and/or ending data point. Default value is NULL which doesn't fix any point. Available options are: "start" for fixing the starting point, "end" for fixing the ending point and "both" for fixing both ends of the data.

altFilter

set special filter rule to indexes defined in this parameter. Special filter structure: `x'(n) = (2*x(n)+x(n+1))/3`

warn

boolean deciding whether lowpass issues a warning for critical parameter choices or not

Value

The filtered data vector or MAgPIE object

See also

Other TemporalOperations: commonYears(), convergence(), time_interpolate()

Author

Jan Philipp Dietrich, Misko Stevanovic

Examples


lowpass(c(1, 2, 11, 3, 4))
#> [1] 1.25 4.00 6.75 5.25 3.75
# to fix the starting point
lowpass(c(0, 9, 1, 5, 14, 20, 6, 11, 0), i = 2, fix = "start")
#> Warning: Fixing start or end does modify the total sum of values! Use fix=NULL to let the total sum unchanged!
#> [1]  0.0000  3.3750  4.7500  7.4375 11.9375 13.5000 10.8750  6.8750
#> [9]  3.8125