add some comments on soil function for Erick

Functions should be correected

functions/soil.utils.R

@@ -52,6 +52,10 @@ compute.PSoil <- function(REW, alpha_vg, n_vg) {
 #--------------------
 #Campbell
 compute.PSoil.Camp <- function(SWS, tsc, b_camp, psie) {
+  #TODO : correct this
+  # psie : psi air entry (MPA) should be given negative and thus remove the multiplication *-1
+  # b_camp is positive (unitless)
+  
   Psoil <- -1 * (psie * ((SWS / tsc)^-b_camp))
   return(Psoil)
 }
@@ -65,8 +69,10 @@ compute.KSoil.Camp <- function(SWS, tsc, b_camp, Ksat_campbell) {
 #compute.KSoil.Camp(0.1,0.5, -4, 1.69)
 
 compute.thetaAtGivenPSoil.Camp <- function(thetaSat, PsiTarget, psie, b_camp) {
-  
-  thetaAtGivenPSoil =  thetaSat*(PsiTarget/-psie)^(1/-b_camp)
+  #TODO : correct this
+  # psie : psi air entry (MPA) should be given negative and thus remove the multiplication *-1
+  # b_camp is positive (unitless)
+  thetaAtGivenPSoil =  thetaSat*(PsiTarget/-psie)^(-1/b_camp)
   
   return(thetaAtGivenPSoil)
 }