R/polcurve_averager.R

In mikegerhardt/echem: Importing and manipulating data from Gamry potentiostats

# Function to average the top and bottom traces of a polarization curve
# Written by MRG 11/27/2015

#' @describeIn import_cell_cv Function which averages the top and bottom traces
#'   of a polarization curve.
polcurve_averager <- function(inputdf, voltageid = "Vf", currentid = "scurrent"){
  
  inputlength <- length(inputdf[, voltageid])
  
  # Find the voltage/current peaks?
  firstpeak <- which.max(inputdf[1:floor(inputlength/2), voltageid])
  secondpeak <- which.max(inputdf[floor(inputlength/2):inputlength, voltageid]) + floor(inputlength/2)
  midpoint <- (firstpeak + secondpeak)/2
  
  firsttrace <- inputdf[firstpeak:midpoint, currentid]
  secondtrace <- rev(inputdf[(midpoint+1):secondpeak, currentid])
  
  if(length(firsttrace) > length(secondtrace)){
    firsttrace <- firsttrace[1:length(secondtrace)]
  }
  
  if(length(secondtrace) > length(firsttrace)){
    secondtrace <- secondtrace[1:length(firsttrace)]
  }
  
  avgtrace <- (firsttrace + secondtrace)/2
  voltagetrace <- inputdf[firstpeak:(firstpeak + length(avgtrace) - 1), voltageid]
  outputdf <- data.frame(avgcurrent = avgtrace, avgvoltage = voltagetrace, avgpower = avgtrace * voltagetrace)
  return(outputdf)
}