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158 lines
5.3 KiB
R
158 lines
5.3 KiB
R
#' AVS -> SHE
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#'
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#' Converts from absolute vacuum scale (AVS) to SHE scale
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#'
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#' @param avs Potential in AVS scale
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#'
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#' @return potential in SHE scale (numeric)
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#' @export
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AVS2SHE <- function(avs) {
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she <- -(4.5 + avs)
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return(she)
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}
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#' SHE -> AVS
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#'
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#' Converts from SHE scale to absolute vacuum (AVS) scale
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#'
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#' @param she Potential in SHE scale
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#'
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#' @return potential in AVS scale (numeric)
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#' @export
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SHE2AVS <- function(she) {
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avs <- -(4.5 + she)
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return(avs)
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}
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#' ConvertRefPotEC
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#'
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#' This function does the heavy lifting.
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#' Converts from an electrochemical reference scale into another.
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#' SHE: standard hydrogen electrode scale
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#' Ag/AgCl: silver silver-chloride electrode scale (3M KCl)
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#' SCE: standard calomel scale
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#'
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#' @param argpotential potential (numeric)
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#' @param argrefscale input reference scale (character string)
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#' @param valuerefscale output reference scale (character string)
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#'
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#' @return potential in output reference scale (numeric)
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ConvertRefPotEC <- function(argpotential, argrefscale, valuerefscale) {
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##### Add more reference electrodes here >>
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refpotatSHEzero <- c( 0, -0.21, -0.24, 3)
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refrownames <- c( "SHE", "Ag/AgCl", "SCE", "Li/Li+")
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refcolnames <- c("SHE0", "AgCl0", "SCE0", "Li0")
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##### Add more reference electrodes here <<
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#
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SHE0 <- data.frame(matrix(refpotatSHEzero, ncol=length(refpotatSHEzero), byrow=T))
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refpotmtx <- matrix(NA, length(SHE0), length(SHE0))
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refpotmtx[,1] <- matrix(as.matrix(SHE0), ncol=1, byrow=T)
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for (c in 2:length(SHE0)) {
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# loop over columns (except the first)
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for (r in 1:length(SHE0)) {
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# loop over rows
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refpotmtx[r, c] <- refpotmtx[r, 1] - refpotmtx[c, 1]
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}
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}
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refpotdf <- as.data.frame(refpotmtx)
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names(refpotdf) <- refcolnames
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row.names(refpotdf) <- refrownames
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## So far we have made a matrix of all the possible combinations,
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## given the vector refpotatSHEzero. The matrix is not strictly necessary,
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## but it may prove useful later. It does.
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#
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# Match argrefscale to the refrownames
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argmatch <- match(argrefscale, refrownames, nomatch = 0)
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# Match valuerefscale to the refrownames
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valuematch <- match(valuerefscale, refrownames, nomatch = 0)
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# We simply assume that the match was well-behaved
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valuepotential <- argpotential + refpotdf[valuematch, argmatch]
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# Check that arg and value electrodes are within bounds for a match
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if (argmatch == 0 || valuematch == 0) {
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# No match
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# Perform suitable action
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message("Arg out of bounds in call to ConvertRefPot")
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valuepotential <- NA
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}
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return(valuepotential)
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}
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#' Convert from one electrochemical scale to another
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#'
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#' @param argpotential potential (numeric)
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#' @param argrefscale input reference scale (char string)
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#' @param valuerefscale output reference scale (char string)
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#'
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#' @return potential in output reference scale (numeric)
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#' @export
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ConvertRefPot <- function(argpotential, argrefscale, valuerefscale) {
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# You should check that argpotential is valid numeric
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# IDEA: make a matrix out of these (scale names and flags)
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# Valid scales
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scale.names <- list()
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scale.names[["SHE"]] <- c("SHE", "NHE", "she", "nhe")
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scale.names[["AgCl"]] <- c("Ag/AgCl", "AgCl", "ag/agcl", "agcl")
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scale.names[["SCE"]] <- c("SCE", "sce")
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scale.names[["Li"]] <- c("Li/Li+", "Li", "Li+", "li", "li+", "li/li+")
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scale.names[["AVS"]] <- c("AVS", "avs")
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# Set flags
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bool.flags <- as.data.frame(matrix(0, nrow = length(scale.names), ncol = 2))
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names(bool.flags) <- c("argref", "valueref")
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row.names(bool.flags) <- names(scale.names)
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# argrefscale
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# Check that argrefscale is valid character mode
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# ...
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for (j in 1:length(row.names(bool.flags))) {
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if (any(scale.names[[row.names(bool.flags)[j]]] == argrefscale)) {
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bool.flags[row.names(bool.flags)[j], "argref"] <- j
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}
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}
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# valuerefscale
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# Check that valuerefscale is valid character mode
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# ...
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for (k in 1:length(row.names(bool.flags))) {
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if (any(scale.names[[row.names(bool.flags)[k]]] == valuerefscale)) {
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bool.flags[row.names(bool.flags)[k], "valueref"] <- k
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}
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}
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# Depending on which flags are set, call the corresponding function
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decision.vector <- colSums(bool.flags)
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# Check if both scales are the same (no conversion needed). If so, abort gracefully.
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# ...
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if (decision.vector["argref"] == 5 || decision.vector["valueref"] == 5) {
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# AVS is requested, deal with it it
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if (decision.vector["argref"] == 5) {
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# Conversion _from_ AVS
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rnpotential <- ConvertRefPotEC(AVS2SHE(argpotential),
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"SHE",
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scale.names[[decision.vector["valueref"]]][1])
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}
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if (decision.vector["valueref"] == 5) {
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# Conversion _to_ AVS
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rnpotential <- SHE2AVS(ConvertRefPotEC(argpotential,
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scale.names[[decision.vector["argref"]]][1],
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"SHE"))
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}
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} else {
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rnpotential <- ConvertRefPotEC(argpotential,
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scale.names[[decision.vector["argref"]]][1],
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scale.names[[decision.vector["valueref"]]][1])
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}
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return(rnpotential)
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}
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