Added function LinearBaseline().

common.R

@@ -3,6 +3,7 @@
 # Taha Ahmed, Jan 2011
 
 # CONTENTS
+# >>>> LinearBaseline
 # >>>> int2padstr
 # >>>> It2charge
 # >>>> ProvideSampleId
@@ -15,6 +16,33 @@
 
 
 
+##################################################
+################ LinearBaseline ##################
+##################################################
+LinearBaseline <- function (potential, current, iplim) {
+   ## Arguments:
+   ##   potential: full half-cycle, potentials
+   ##     current: full half-cycle, currents
+   ##       iplim: interpolation limits along x (potential)
+   ## Value:
+   ##   A dataframe with two columns, potential and current
+   ##   (of the calculated baseline)
+   # Construct potential-current dataframe
+   sweep <- data.frame(potential = potential, current = current)
+   #
+   sweep.iplim <- subset(subset(sweep, potential > iplim[1]), potential < iplim[2])
+   sweep.baseline <- data.frame(potential = approxExtrap(sweep.iplim$potential,
+      sweep.iplim$current, xout = sweep$potential, method = "linear")$x,
+      current = approxExtrap(sweep.iplim$potential, sweep.iplim$current, 
+      xout = sweep$potential, method = "linear")$y)
+   sweep.data <- data.frame(potential = sweep.baseline$potential,
+      current = sweep.baseline$current)
+   return(sweep.data)
+}
+
+
+
+
 ##################################################
 ################## int2padstr ####################
 ##################################################