Calculus {Rsac}R Documentation

Differentiation and Integration

Description

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.

Usage

dif(s)
int(s)

Arguments

s an object of class "rsac".

Value

same as input.

Author(s)

Eric M. Thompson <eric.thompson@tufts.edu>

See Also

rtrend

Examples


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)

[Package Rsac version 0.1-7 Index]