R/Layer1RelativeError.R

In ak-git/RSM: Resistivity Sounding Measurements

source("R/rsm.R")

layer1RelError <- function(smm, lmm, relError) {
  abs(smm) -> smm
  abs(lmm) -> lmm
  max(smm, lmm) * relError * sign(lmm - smm) -> err
  layer1Inverse(smm - err, lmm + err, layer1Ohms(1.0, smm, lmm)) -> inverse
  return(abs(inverse - 1.0))
}

relErrorFactor <- function(x) {
  if (x > 1) {
    1 / x -> x
  }
  return((1 + x) / (x * (1 - x)))
}

exp(seq(log(0.2), log(5), length.out = 100)) -> sToL
sapply(sToL, relErrorFactor) -> y
par(mar = c(5, 6, 1, 1))
plot(sToL, y, type = "l", lwd = 2, ylim = c(5, 20), log = 'xy',
     xlab = expression(bold(frac(s, L))),
     ylab = expression(bold(frac(delta ~ rho, delta ~ L)))
)
sqrt(2) - 1 -> xmin1
sqrt(2) + 1 -> xmin2
points(xmin1, relErrorFactor(xmin1))
points(xmin2, relErrorFactor(xmin2))
abline(h = c(5, 10, 15, 20), col = 'black', lty = 1, lwd = 0.5)
abline(v = c(0.5, 1, 2), col = 'black', lty = 1, lwd = 0.5)
abline(h = relErrorFactor(xmin1), col = 'black', lty = 2, lwd = 1.5)
text(xmin1, relErrorFactor(xmin1), expression(sqrt(2) - 1), pos = 1)
text(xmin2, relErrorFactor(xmin2), expression(sqrt(2) + 1), pos = 1)
text(0.18, relErrorFactor(xmin2), expression(~3 + 2 * sqrt(2)), pos = 4, srt = 90)