Calculus {Rsac} | R Documentation |
Differentiation (by two-point differencing) and integration (by
rectangular approximation) in the time domain. For differentiation,
the begining time of the time series is increased by half the sampling
interval, and the length of the record is decreased by 1. It is also
usually a good idea to use the rtrend
or
rmean
function before integration.
dif(s) int(s)
s |
an object of class "rsac" . |
same as input.
Eric M. Thompson <eric.thompson@tufts.edu>
data(srosa) getunits(srosa) # convert to cm/s/s srosa.accel <- dif(mul(srosa, 1e-7)) amax <- function(X) X$x <- max(abs(X$amp)) pga <- max(sapply(X = srosa.accel, amax)) # cm/s/s spect(srosa) srosa.disp <- int(rtrend(srosa)) plot(srosa, xlim = c(100, 400)) plot(srosa.disp, xlim = c(100, 400)) srosa.disp <- hp(srosa.disp, c = 0.1) plot(srosa.disp, xlim = c(100, 400)) spect(srosa.disp)