diff --git a/DESCRIPTION b/DESCRIPTION
index 10e8fb115712cbdf7be46416cd233195c6b50c46..27c5f0b1c5c5699d1c458aadfa350d70d6676d02 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,8 +1,8 @@
 Package: airGR
 Type: Package
 Title: Suite of GR Hydrological Models for Precipitation-Runoff Modelling
-Version: 1.1.2.39
-Date: 2019-01-29
+Version: 1.1.2.40
+Date: 2019-01-30
 Authors@R: c(
   person("Laurent", "Coron", role = c("aut", "trl"), comment = c(ORCID = "0000-0002-1503-6204")),
   person("Charles", "Perrin", role = c("aut", "ths"), comment = c(ORCID = "0000-0001-8552-1881")),
diff --git a/NEWS.rmd b/NEWS.rmd
index 65a9529cbdaabd08d5f9f476a98c17ae9adab69c..c0cd39a88bca3531bfc805679d025b5387c04641 100644
--- a/NEWS.rmd
+++ b/NEWS.rmd
@@ -13,7 +13,7 @@ output:
 
 
 
-### 1.1.2.39 Release Notes (2019-01-29) 
+### 1.1.2.40 Release Notes (2019-01-30) 
 
 
 
diff --git a/R/TransfoParam_CemaNeige.R b/R/TransfoParam_CemaNeige.R
index d49d600d1c3b47024091dd635021a2ddec895da8..4754595ea2caa3db2259b76633bd4ec2c5f344a4 100644
--- a/R/TransfoParam_CemaNeige.R
+++ b/R/TransfoParam_CemaNeige.R
@@ -1,31 +1,39 @@
 TransfoParam_CemaNeige <- function(ParamIn, Direction) {
   
-  NParam <- 2
-  Bool <- is.matrix(ParamIn)
-  
-  if (Bool == FALSE) {
-    ParamIn <- rbind(ParamIn)
+
+  NParam <- 2L
+  
+  
+  ## check_arguments
+  Bool <- is.vector(ParamIn)
+  if (Bool) {
+    ParamIn <- matrix(ParamIn, nrow = 1)
+    warning("'ParamIn' automatically convert to 'matrix'")
+  }  
+  if (!inherits(ParamIn, "matrix")) {
+    stop("'ParamIn' must be of class 'matrix'")
+  }
+  if (!inherits(Direction, "character") | length(Direction) != 1 | any(!Direction %in% c("RT", "TR"))) {
+    stop("'Direction' must be a character vector of length 1 equal to 'RT' or 'TR'")
   }
-  
   if (ncol(ParamIn) != NParam) {
-    stop(paste( "the CemaNeige module requires ", NParam, " parameters \n", sep = "" ))
-    return(NULL)
+    stop(sprintf( "the CemaNeige module requires %i parameters", NParam))
   }
   
+  
   if (Direction == "TR") {
     ParamOut <-  ParamIn
     ParamOut[, 1] <- (ParamIn[, 1] + 9.99) / 19.98 ### CemaNeige X1 (weighting coefficient for snow pack thermal state)
     ParamOut[, 2] <- exp(ParamIn[, 2]) / 200       ### CemaNeige X2 (degree-day melt coefficient)
   }
-  
   if (Direction == "RT") {
     ParamOut <-  ParamIn
     ParamOut[, 1] <-  ParamIn[, 1] * 19.98 - 9.99  ### CemaNeige X1 (weighting coefficient for snow pack thermal state)
     ParamOut[, 2] <- log(ParamIn[, 2] * 200)       ### CemaNeige X2 (degree-day melt coefficient)
   }
   
-  if (Bool == FALSE) {
-    ParamOut <- ParamOut[1, ]
+  if (Bool) {
+    ParamOut <- as.vector(ParamOut)
   }
   
   return(ParamOut)