R/depthScale.R

In increasechief/chromastar: Pedagogical Stellar Atmposhere and Spectrum Modelling of Stars

## MIT License
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## Copyright (c) 2018 Oliver Dechant
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depthScale <- function(numDeps, tauRos, kappa, rho) {
  #returns vector of numDep linear geometric DEPTHS below top of atmosphere in
  #cm (cgs) for consistency with log(g) units

  logE <- log10(exp(1))

  #starts at this depth index - the topmost layers have such low rhos that they
  #correspond to huge geometric depths
  iStart <- 1
  z1 <- 1E-19
  depths <- rep(z1, numDeps)

  logHelp <- tauRos[iStart,2]-kappa[iStart,2]-rho[iStart,2]
  helpNext <- exp(logHelp)

  help <- helpNext

  for (i in (iStart+1):numDeps) {
    #trapezoid method
    deltaX <- tauRos[i,2]-tauRos[(i-1),2]
    logHelp <- tauRos[i,2]-kappa[i,2]-rho[i,2]
    helpNext <- exp(logHelp)
    deltaZ <- deltaX*(0.5*(help+helpNext))
    z2 <- z1+deltaZ
    depths[i] <- z2
    z1 <- z2
    help <- helpNext
  }

  depths
}